Keynote and Oral Papers

European Journal of Phycology

ISSN: 0967-0262 (Print) 1469-4433 (Online) Journal homepage: https://www.tandfonline.com/loi/tejp20

To cite this article: (2015) Keynote and Oral Papers, European Journal of Phycology, 50:sup1, 22-120, DOI: 10.1080/09670262.2015.1069489 To link to this article: https://doi.org/10.1080/09670262.2015.1069489

Published online: 20 Aug 2015.

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Full Terms & Conditions of access and use can be found at https://www.tandfonline.com/action/journalInformation?journalCode=tejp20 Keynote and Oral Papers 1. Algal diversity and species delimitation: new tools, new insights

1KN.1 1KN.2 HOW COMPLEMENTARY BARCODING AND GENERATING THE DIVERSITY - POPULATION GENETICS ANALYSES CAN UNCOVERING THE SPECIATION HELP SOLVE TAXONOMIC QUESTIONS AT MECHANISMS IN FRESHWATER AND SHORT PHYLOGENETIC DISTANCES: THE TERRESTRIAL MICROALGAE EXAMPLE OF THE BROWN ALGA Š PYLAIELLA LITTORALIS Pavel kaloud ([email protected]) Christophe Destombe1 ([email protected]), Department of Botany, Charles Univrsity in Prague, Alexandre Geoffroy1 ([email protected]), Prague 12801, Czech Republic Line Le Gall2 ([email protected]), Stéphane Mauger3 ([email protected]) and Myriam Valero4 Species are one of the fundamental units of biology, ([email protected]) comparable to genes or cells. Understanding the general patterns and processes of speciation can facilitate the 1Station Biologique de Roscoff, Sorbonne Universités, formulation and testing of hypotheses in the most impor- Université Pierre et Marie Curie, CNRS, Roscoff tant questions facing biology today, including the fitof 29688, France; 2Institut de Systématique, Evolution, organisms to their environment and the dynamics and Biodiversité, UMR 7205 CNRS-EPHE-MNHN-UPMC, patterns of organismal diversity. Though eukaryotic Muséum National d’Histoire Naturelle, Paris 75231, microorganisms are extremely numerous, diverse and France; 3Station Biologique de Roscoff, CNRS, essential in global ecosystem functioning, they are lar- Sorbonne Universités, Université Pierre et Marie gely understudied by evolutionary biologists compared Curie, Roscoff 29688, France and 4Station Biologique with multicellular organisms. In part owing to their small de Roscoff, CNRS, Sorbonne Universités, Université sizes and difficulty in culturing, our knowledge of their Pierre et Marie Curie, Roscoff 29688, France diversity and evolutionary processes is considerably limited. In particular, very little is known about specia- The great phenotypic variability and the lack of diag- tion mechanisms generating the diversity of microalgae. nostic characters in the genus Pylaiella render the sys- In this talk, I will present several examples of speciation tematic study of this genus problematic. In the present mechanisms detected in freshwater and terrestrial algae, study, we investigated the diversity of Pylaiella littor- including limited dispersal, natural polyploidization, and alis (Linnaeus) Kjellman along the Brittany (France) ecological divergence. In general, climatic- and coast using a DNA barcoding multilocus approach with habitat-niche differentiation seems to represent the mitochondrial (cox1, nad1andatp9) and chloroplastic most important force that drives the origin of new spe- (rbcLandatpB) markers associated with a population cies. Accordingly, despite the cosmopolitan distribution genetics approach using 10 microsatellite markers. In of many eukaryotic microorganisms, local fine-scale addition, spatio-temporal sampling was conducted structuring of ecologically distinct genotypes may repre- along the Brittany coast. Mitochondrial sequence sent the most plausible explanation for their extremely results revealed the occurrence of two cryptic species, high species richness. with a minimum of 2.4% divergence between them. Microsatellite genotypic data recovered three well supported clusters matching the two mtDNA clusters of 1KN.3 Pylaiella. While gene flow is limited between mito- HIGH-CONTENT FLUORESCENCE chondrial clusters, occurrence of genetic admixtures in MICROSCOPY APPLIED TO MARINE some populations suggests that reproductive isolation is PROTISTS ECOLOGY not complete. Our study highlights how the combination of phylogenetic and population genetics Sebastien PM Colin1 ([email protected]), Luis- approaches can help determine algal diversity and Pedro Coelho2 ([email protected]), Volker study boundaries between closely related species. Hilsenstein3 ([email protected]), Rainer

Published online 20 Aug 2015 Keynote and Oral Papers 23

Pepperkok3 ([email protected]), Eric Karsenti4 targeting diverse biological function, in order to tackle ([email protected]), Chris Bowler5 (cbowler@ all sorts of ecological questions. biologie.ens.fr) and Colomban de Vargas1 (vargas@sb- roscoff.fr)

1Adaptation and Diversity in the Marine 1OR.1 Environment, CNRS-UPMC Station Biolgogique de 2 GAPS TO FILL WHEN ANALYZING Roscoff, Roscoff 29680, France; Structural and FRESHWATER DIATOM DIVERSITY WITH Computational Biology, European Molecular Biology – 3 DNA BARCODING NOTES FROM A Laboratory, Heidelberg 69117, Germany; Advanced BOREAL REGION Light Microscopy Facility, European Molecular 1 Biology Laboratory, Heidelberg 69117, Germany; Maria Kahlert ([email protected]), Agnes 2 4Director’s research, European Molecular Biology Bouchez ([email protected]), Philippe 3 Laboratory, Heidelberg 69117, Germany and 5Institut Chaumeil ([email protected]), 3 de Biologie IBENS, ENS CNRS, PARIS 75005, France Alain Franc ([email protected]), Jean-Marc Frigerio3 (Jean-Marc.Frigerio@pierroton. The mainstream tool in marine ecosystems biology is inra.fr), Frederic Rimet2 ([email protected]. massive DNA sequencing, allowing detailed inventory fr), Franck Salin3 ([email protected])and of microbial environmental genetic diversity. However, Valentin Vasselon 2 ([email protected]) the large majority of meta-omics data, in particular in 1 eukaryotic size-fractions, are not yet assigned to any Department of Aquatic Sciences and Assessment, described organisms. This greatly limits our under- Swedish University of Agricultural Sciences, 2 standing of the ecosystemic and biogeochemical func- Uppsala 750 07, Sweden; INRA, UMR CARRTEL, 3 tions of the genetically unveiled diversity. Linking Thonon-les-Bains 74200, France and INRA, UMR environmental genes and genomes to organismal phe- BIOGECO, Cestas 33610, France notypes and morphology is arguably one of the next big challenge in ecosystems ecology. Few available in- The idea of using DNA metabarcoding as a more reli- flow imaging technologies (FlowCytoBot, CytoSense, able and most of all cost-effective tool for environmental ImageStream, FlowCAM . . .) propose a valuable ima- assessment based on freshwater benthic diatom biodi- ging rate that may match Next Generation Sequencing versity has enchanted stakeholders now asking when sensitivity. Unfortunately, the trade-off between speed these tools will be available for routine usage. and image quality significantly impacts the images However, traditional methods using diatom taxa data information content and limits analyses to relatively generated by microscopical identification have a good narrow organismal size ranges. We developed a novel rumor to be very effective tools in the assessment of strategy – we call e-HCFM for environmental water quality status, and we should be careful to just High-Content Fluorescence Microscopy – directly exchange methods. Before molecular data can become a inspired from high-throughput quantitative fluores- standard for assessing algal diversity in environmental cence microscopy for cell biology. Our protocol assessment, we need to compare the results of both to includes planktonic cells fixation/multi-staining/ analyze advantages and drawbacks of each method. mounting/automated imaging and taxonomic annota- Here, we present a first analysis of a setup of ecologi- tion. The fluorescent labeling strategy aims at making cally very different streams of Sweden in a quantitative visible all eukaryotic cells by highlighting a few key comparison of DNA metabarcoding (rbcL barcode) and features: nuclei, compartmentalization (i.e. mem- microscopical counts. We used using next-generation branes), chloroplast and exo-skeleton. The use of sequencing, a dedicated bioinformatics pipeline and a Confocal Laser Scanning Microscopy (CLSM) allows curated DNA reference library. Many of the dominating 3D-imaging analysis of the wide range of cell size and diatom species of the boreal region were missing in the morphologies displayed by planktonic protists. It sig- database, which complicated the methods comparison. nificantly improves the quality and quantity of mea- Still, even when taxa were represented in the reference surements extracted from each imaged cells. e-HCFM database, we found quite a large number of taxa being may bring critical information on eukaryotic cells detected by only one of the methods. We hypothesize shape, volumes, and organelles, contributing to both that at least a part of this difference depends on the automated taxonomic identification and recognition of choice of the barcoding gap, because we found that the key biological and biogeochemical features at the sin- relative abundance of certain taxa decreased or increased gle-cell level, including life-cycle stages and potential depending on which gap was used for the reads assign- symbioses sensu lato. A case-study based on samples ment. We suggest that the barcoding gap should be from the Tara Oceans expedition is presented. The adapted to the clade in question, as it is not homogenous primary version e-HCFM described herein can be among different diatom groups. Our perspective is to used as a backbone for several staining protocols achieve more complete and correct taxa lists for both Keynote and Oral Papers 24 methods as another step for the routine usage of meta- ([email protected]) and Peter Raimondi2 (raimondi barcoding methods in the future. @ucsc.edu)

1OR.2 1CCMAR, University of Algarve, Faro 8005-139, GENDER STUDIES IN SEAWEEDS - Portugal and Department of Ecology and EXPRESSION AND EVOLUTIONARY RATES Evolutionary Biology, University of California Santa OF SEX-BIASED GENES IN FUCOID BROWN Cruz, Long Marine Laboratory, Santa Cruz CA ALGAE 95060, USA Gareth A Pearson ([email protected]) Modern molecular tools are contributing to a renewed interest in the roles of hybridization and polyploidy in Centre of Marine Sciences, University of the Algarve, evolution. These processes combine in allopolyploid Faro 8005-139, Portugal speciation, best known from plants and a few verte- brate lineages. Additional models across the tree of Sexually dimorphic males and females share a largely life may provide new insights underlying the factors common genetic background,leadingtothesuggestion leading to allopolyploid formation, establishment and that gene expression is the major determinant of sexual evolutionary success. We investigated the evolution- phenotype. Sex-biased genes controlling reproductive ary history of Hesperophycus/Pelvetiopsis, a brown functions are candidates having roles in lineage diver- algal (Stramenopiles) seaweed complex, screening a gence and speciation processes. We have analysed sex- diverse panel of populations of Hesperophycus cali- biased expression in several members of the family fornicus and Pelvetiopsis limitata senso lato using a Fucaceae by comparing the transcriptomes of reproduc- variety of nuclear/organelle sequencing/typing mar- tive tissues, and used sequence information to study kers. Four species were recovered, including P. arbor- patterns of adaptive evolution in a phylogenetic frame- escens (taxonomically unclear previously) and a new work. Comparative transcriptomics of male and female unrecognized species. Gene paraphyly, cyto-nuclear reproductive tissue against the vegetative background in conflict, fixed heterozygosity and allele states strongly Fucus vesiculosus revealed many more male-biased supported the allopolyploid nature of two of these (MBG) than female-biased genes (FBG); 1,127 and entities and the male contribution of P. arborescens 174 transcripts, respectively. Expression analysis of to both. P. arborescens has an extremely reduced and orthologues showed that MBG were more consistently non-overlapping geographical distribution compared sex-biased across different species than FBG. This with the most recent (and possibly still expanding) might be related both to male specialization (e.g., the fl allopolyploid taxa. Conversely, the older allopoly- presence of agella uniquely in sperm cells), and to ploid is presently the most widespread taxa, although female functional pleiotropy. Specialization was illu- its maternal ancestral is probably extinct. Our results strated by the fact that over 60 % of MBG in F. vesicu- provide evidence for ecological divergence allowing losus were uniquely-expressed in male reproductive allopolyploids to locally co-exist with diploid parental tissue. These male-unique genes (MUG) showed dis- species, which may even be outperformed in the long tinctive evolutionary patterns, including reduced codon- term. bias compared with female-, or non-biased genes (i.e., reduced GC3 content, and higher effective number of codons), suggesting relaxation of selective pressure for 1OR.4 fi translational ef ciency and/or accuracy. Analysis of 439 ELUCIDATING UNRESOLVED INVASION genes with codon-based branch-site models of adaptive HISTORY WITH GENOME-WIDE evolution showed that the number of sites under positive SEQUENCING APPROACH: THE CASE OF selection was greatest in the MUG group, followed by THE GLOBAL INVADER SARGASSUM MBG, FBG and non-biased genes. Together, our results MUTICUM suggest that tissue-specific expression is linked to reduced selective and/or pleiotropic constraint, which SabrinaLeCam([email protected]), Claire in turn may drive accelerated rates of adaptive Daguin Thiébaut ([email protected]), Sarah divergence. Bouchemousse ([email protected]) and Frédérique Viard ([email protected]) 1OR.3 Team DivCo, CNRS Station biologique de Roscoff, PHYLOGENETIC AND BIOGEOGRAPHICAL Roscoff 29680, France PATTERNS OF ALLOPOLYPLOID SPECIATION IN AN INTERTIDAL FUCOID The brown seaweed Sargassum muticum is one of the SEAWEED ASSEMBLAGE most emblematic non-indigenous seaweed species. João Neiva1 ([email protected]), Laura Anderson2 Native to Asia, it has successfully invaded the North- ([email protected]), Ester A Serrão1 Eastern Pacific coasts since the 1940s and the Keynote and Oral Papers 25

North-Eastern Atlantic since the 1970s. Introduction Sorbonne Universités, Paris 75005, France and history in these two areas remained unresolved because 4Phycology Research Group, Ghent University, Ghent introduced populations were found to be genetically 9000, Belgium monomorphic. For instance, a previous study showed that all 1200 individuals, from 46 introduced American The subclass Corallinophycidae encompasses four and European populations, shared the exact same orders of benthic red algae unique by the presence of multi-locus genotype at 14 microsatellites. To under- calcite. While the order Rhodogorgonales is a stand this pattern, and elucidate the invasion history of species-poor and mainly a tropical group of gelatinous S. muticum, we developed a genotyping-by-sequencing algae with calcification limited to calcite husks, the method (ddRadseq), for thr firsttimeinaninvasive orders Sporolithales, Hapalidiales and Corallinales are seaweed. Large scale libraries were successfully diverse and widely distributed, characterized by having sequenced for 303 individuals from 21 populations calcified walls and highly variable morphology. Despite (Europe: 9, North-West America: 7 and Japan: 5). recent clarification of phylogenetic relationships, the Conversely to previous studies, genetic polymorphism origin and evolution of this group is still controversial. was detected in the introduced populations with 2026 Based on the presence of distinctive anatomical features, SNPs(He=0.15and0.12inAmericanandEuropean the literature dated back the first fossil records in the areas respectively). Nevertheless, much larger diversity early Cretaceous (140 Mya); however, the presence of was found in the native range and, as expected, severe ancient extinct taxa resembling coralline red algae could founder events were evidenced in the introduction suggest an earlier origin back to the Neoproterozoic (ca. ranges. A decreasing number of polymorphic loci was 600 Mya). In this study we will apply a molecular observed between the native range, NW America and evolution approach integrating comprehensive molecu- Europe (1259, 455 and 232 respectively) as well as lar data and fossil records toward estimating the degree strong genetic similarities between America and of genetic divergence among lineages and their time of Europe; both supporting predictions of a secondary evolutionary divergence as well as the age of their most introduction in Europe from America where S. muticum recent common ancestor. This approach will involve was introduced earlier. Genetic structure was observed phylogenetic analyses of molecular data obtained for within each introduction range. In Europe, the seven genes (cox1, psbA, rbcL, 23S rRNA, SSU Mediterranean and Portuguese populations differed sig- rRNA, LSU rRNA and EF2), and the revision of avail- nificantly and in America, populations from the Puget able literature on taxonomy, phylogeny and systematics Sound were highly differentiated from those of southern for all the genera currently accepted taxonomically. An California. While the link between genetic diversity and exhaustive list of fossil records encompassing different invasion success has often been highlighted in marine genera will be compiled in order to obtain the most systems, our results document a success story of a global accurate timeline for calibrating the Corallinophycidae invasion with limited genetic polymorphism. More gen- phylogeny. Diagnostic characters employed for the dis- erally, they confirm the relevance of genome-wide stra- tinction at the suprageneric level pertaining to the three tegies to investigate the genetic diversity of weakly phases of their life cycle will be also analysed in order to polymorphic algal species. select characters, which have relevant signal in light of the evolution of coralline algae inferred from our 1OR.5 phylogeny. EVOLUTIONARY ORIGIN OF CORALLINE RED ALGAE (CORALLINOPHYCIDAE, 1OR.6 RHODOPHYTA) INFERRED FROM MULTILOCUS TIME-CALIBRATED THE PATHOGENS OF BROWN ALGAE PHYLOGENY ANISOLPIDIUM ECTOCARPII AND 1 2 ANISOLPIDIUM ROSENVINGEI DEFINE A Viviana Peña ([email protected]), Juan Carlos Braga 2 NEW CLASS OF MARINE ANTERIORLY ([email protected]), Julio Aguirre ([email protected]), 2 3 UNICILIATE OOMYCETES Anja Rösler ([email protected]), Line Le Gall ([email protected]) and Olivier De Clerck4 (olivier. Claire MM Gachon1 ([email protected]), Kyle I [email protected]) Fletcher2 (k.fl[email protected]), Yacine Badis1 ([email protected]), Pieter van West3 (p.van- 1BIOCOST Research Group, Universidade da Coruña, [email protected]) and Dieter G Müller4 (dieter.ger- A Coruña 15071, Spain; 2Departamento de [email protected]) Estratigrafía y Paleontología, Universidad de Granada, Granada 18002, Spain; 3Equipe Exploration, Espèces 1Microbial and Molecular Biology, Scottish et Evolution, Institut de Systématique, Evolution, Association for Marine Science, Oban PA37 1QA, Biodiversité, UMR 7205 ISYEB CNRS, MNHN, UPMC, United Kingdom; 2Oceanlab, University of Aberdeen, EPHE, Muséum national d’Histoire naturelle (MNHN), Newburgh AB41 6AA, United Kingdom; 3Aberdeen Keynote and Oral Papers 26

Oomycete Laboratory, Institute of Medical Sciences, 4Ecology Assessment Unit, Scottish Environment Aberdeen AB25 2ZD, United Kingdom and Protection Agency (SEPA), Holytown ML1 4WQ, 4Fachbereich Biologie, Universitaet Konstanz, United Kingdom; 5Marine Bioscience, Fukui Konstanz D-78457, Germany Prefectural University, Obama Fukui 917-0003, Japan and 6Palaeoceanology Unit, University of Despite their abundance in the field, and their suspected Szczecin, Szczecin 70-383, Poland role in regulating the abundance of their host population, hyphochytrid pathogens of brown algae have been Nitzschia Hassall is now probably the largest single hardly studied. Using laboratory cultures, we document genus of diatoms (perhaps 1000 species), split in >10 here the life cycle of Anisolpidium ectocarpii, a patho- sections (Cleve & Grunow 1880). It is also remarkable gen of Ectocarpus and other filamentous brown algae, for being highly diverse: with respect to its ecology and present preliminary observations on Anisolpidium (e.g. common and often abundant in freshwater, brack- rosenvingei. Consistent with earlier reports, the zoos- ish and marine habitats; some species recognised as pores of both species have a single anterior flagellum, bioindicators of organic or metal pollution, etc), phy- which justified the placement of Anisolpidium amongst siology (e.g. phototrophs, heterotrophs, mixotrophs), the Hyphochytridiales (Hyphochytridiomycota). life cycle (e.g. homo- and heterothallic, automictic, Unexpectedly, nuclear (SSU rRNA) and mitochondrial avoiding size reduction). However, Nitzschia is also (cox 1, cox2) markers regroup A. rosenvingei, A. ecto- notorious for its taxonomic difficulty: several species carpii and other marine environmental sequences have very few diagnostic characters in the LM. into a hitherto unrecognised monophyletic clade Furthermore, based on morphology several genera within the oomycetes (Oomycota), most closely have been separated from Nitzschia (e.g. Tryblionella, related to the Olpidiopsidiales and Haliphthorales. Psammodictyon, Simonsenia) but their interrelation- The Anisolpidium genus is therefore entirely distinct ships are still unclear. We assembled a four-gene data from the Hyphochytridiales and represents the first set (nuclear LSU and SSU, plastid rbcLandpsbC) of unquestionable instance of an anteriorly uniciliate several species of Nitzschia and related genera. oomycete. We also show that A. ectocarpii can Analysis shows that Nitzschia and even some of its complete its infection cycle in a broad selection of sections are non-monophyletic as previously suggested species from various brown algal orders, suggesting by some single or two-gene phylogenies. Our results that species delimitation within the genus also pin point characters that have been conservative Anisolpidium should not merely be based on the during evolution (e.g. ultrastructure of striae or systems identity of the algal host, as is presently the case. of strips found in the auxospore wall), whereas auto- Finally, a working hypothesis is generated in an mixis has evolved at least twice independently in attempt to establish a new criterion for the separa- Nitzschia sect. Lanceolatae. tion of hyphochytrids from oomycetes, based on the point of zoospore cleavage. 1OR.8 THE ORIGIN OF DIVERSITY IN GREEN 1OR.7 ALGAE A MOLECULAR APPROACH TO NITZSCHIA: Marc Krasovec1 ([email protected]), ESTABLISHING A FRAMEWORK FOR Sophie Sanchez-Ferandin1 (sophie.sanchez- CLASSIFYING A HIGHLY DIVERSE AND [email protected]), Adam Eyre-Walker2 (a.c. TAXONOMICALLY DIFFICULT DIATOM [email protected]) and Gwenaël Piganeau3 GROUP ([email protected]) Rosa Trobajo1 ([email protected]), David G Mann2 ([email protected]), Chunlian Li 3 1Integrative Biology of Marine Organisms, UMR ([email protected]), Laia Rovira4 (laia. 7232, Pierre and Marie Curie University, Banyuls sur [email protected]), Shinya Sato5 (ssato@fpu. mer 66650, France; 2Evolution, Behaviour and ac.jp), Przemysław Dąbek6 (przemyslaw.debek@univ. Environment, University of Sussex, Brighton BN1 szczecin.pl) and Andrzej Witkowski6 (witkowski@ 9RH, United Kingdom and 3Integrative Biology of univ.szczecin.pl) Marine Organisms, UMR 7232, CNRS, Banyuls sur mer 66650, France 1Aquatic Ecosystems, Institute for Food and Agricultural Research and Technology (IRTA), Sant Mutations are the main drivers of diversity and specia- Carles de la Rapita 43540, Spain; 2Science Division, tion. They generate the genetic diversity natural selec- Royal Botanic Garden Edinburgh, Edinburgh EH3 tion acts upon. Exploring the process of mutation is 5OR, United Kingdom; 3Palaeoceanology Unit, fundamental for our understanding the diversification University of Szczecin, Szczecin 70-383, Poland; and the evolution of eukaryotes. The spontaneous Keynote and Oral Papers 27 mutation rate is currently available for a few model natalensis. Broad predictions of a specimen’s phylo- organisms including the freshwater green alga, geny, based on representatives of its secondary meta- Chlamydomonas reinhardtii. We will present the results bolome, proved viable. Related species possess similar of mutation accumulation experiments in five strains of chemical profiles, e.g. L. complanata, L. sodwaniensis unicellular haploid marine green algae; 4 sp. nov. and L.multiclavata sp.nov. produced similar Mamiellophyeae (Ostreococcus tauri, O. mediterra- metabolites to their sister species as inferred by the neus, Micromonas pusilla, Bathycoccus prasinosi) and rbcL phylogeny. In addition, a 1H NMR profiling one Trebouxiophyceae (Picochlorum spp.). These phy- study on the crude organic extracts of various toplanktonic organisms are at the base of the food web in Laurencia species generated distinctive, reproducible coastal oceanic areas. Their genome sizes from 13 Mb to spectra, showing the value of NMR spectroscopy as a 22 Mb and their GC composition from 46 to 65% makes rudimentary species discernment tool. them ideal species to investigate the interplay between genome architecture and mutation rates. The mutation rate is assessed by whole genome re-sequencing of one mother line and an average of 30 lines maintained for 1OR.10 5000 generations per species. SPECIES DIVERSITY AND MOLECULAR PHYLOGENY OF THE CRUSTOSE CORALLINE ALGAE (CORALLINALES, 1OR.9 RHODOPHYTA) FROM THE WARM WATER CHEMISTRY MEETS BIOSYSTEMATICS: WESTERN PACIFIC OCEAN WITH AN PARALLEL STUDIES ON THE DIVERSITY OF EMPHASIS ON SPECIES FROM TAIWAN THE LAURENCIA COMPLEX Showe-Mei Lin1 ([email protected]), Li-Chia Liu1 (RHODOMELACEAE, RHODOPHYTA) IN ([email protected]) and Claude Payri2 (claude. SOUTH AFRICA [email protected]) Jameel Fakee1 ([email protected]), 1Institute of Marine Biology, National Taiwan Ocean Caitlynne Francis2 ([email protected]), University, Keelung City 20224, Taiwan and 2Institut de Denzil Beukes3 ([email protected]), Lydiane Recherche pour le Développement, UMR ENTROPIE, Mattio4 ([email protected]), Robert J Noumea 98818/98800, New Caledonia (French) Anderson5 ([email protected]) and John J Bolton6 ([email protected]) Crustose coralline algae (CCA) are important marine producers and play a critical role in marine ecosystem 1School of Pharmacy, Rhodes University, Grahamstown including many reef-building species. CCA are classi- 6140, South Africa; 2Biological Sciences, University of fied into two red algal orders - the Corallinales and Cape Town, Cape Town 7701, South Africa; 3School of Sporolithales, which are characterized by having calcar- Pharmacy, University of the Western Cape, Bellvillle eous deposits within the cell walls and all reproductive 7535, South Africa; 4School of Plant Biology, University structures developing in conceptacles or pits. Previous of Western Australia, Crawley 6009, Australia; 5Branch taxonomic records of CCA in Taiwan were solely based Fisheries, Department of Agriculture, Forestry and on morphological observations. Our present study is the Fisheries, Roggebaai 8012, South Africa and first attempt to apply for a molecular tool for document- 6Department of Biological Sciences, University of Cape ing the species diversity and inferring their intra- and Town, Rondebosch 7701, South Africa interspecific relationships based on psbA and SSU The Laurencia complex is one of the most studied algal sequence analyses. In this study, more than 100 CCA groups with regard to secondary metabolites. A taxo- collections were collected and sequenced from Taiwan nomic study in South Africa, using morphology and and the neighbouring islands. Seven natural assem- anatomy as well as sequencing of the rbcL marker, has blages (= genera) and more than 18 subclades (= spe- raised the diversity from an initial 10 species of cies) were revealed based on two gene phylogenetic Laurencia, to 14 species (including 5 described as analyses. In particular, one large assemblage contains new), and produced the first records of Palisada, some undescribed species positioned within the Chondrophycus and Laurenciella. This has increased Lithothamnion/Mesophyllum/Phymatolithon complex. fi the known South African species to 19, plus 6 potential We will further test the signi cance of the morphological taxa to be described. Isolation and detailed character- characters currently used for separating Mesophyllum ization of secondary metabolites of 8 of these species, and Phymatolithon and related genera. More samplings including two of the new species, produced 31 com- and phylogenetic analyses will be conducted to unravel pounds, some of them original. Algoane, which was the species diversity and their biogeographic relation- fi previously only reported from a sea-hare, proved to be ships in the warm water western Paci c Ocean in order a unique marker compound isolated from Laurencia to understand their evolutionary histories. Keynote and Oral Papers 28

1OR.11 collections treated in a wide range of drying and storage LITHOPHYLLUM CONGESTUM conditions still provide short but informative sequences (rbcL 300 bp, psbA 600 bp); ii) Mediterranean collec- (CORALLINALES, RHODOPHYTA) WHAT fi ARE YOU AND WHAT AREN’T YOU? tions identi ed as Lithophyllum stictaeforme does not RECEIVING SOME INNER SIGNALS FROM match the genetic information of L. congestum obtained DNA AND MORPHO-ANATOMY TO CLARIFY from type and herbarium material, suggesting that the OUR UNDERSTANDING ON THE SPECIES synonymization is incorrect; iii) PsbA sequences of Lithophyllum congestum from the Caribbean are identi- 1 Jazmin J Hernandez-Kantun ([email protected]), cal and possibly conspecific with specimens from 2 Nestor Robinson ([email protected]), Madagascar, Australia and Japan, but also with some 3 4 Viviana Peña ([email protected]), Paul Gabrielson records identified as L. kotschyanum, changing previous ([email protected]), Rafael Riosmena- schemes on its distribution range. This case study on 5 6 Rodriguez ([email protected]), Line Le Gall Lithophyllum congestum aims to provide new strategies 7 ([email protected]), Fabio Rindi (f.rindi@ and decisions for studies of coralline algae species and 8 univpm.it) and Walter H Adey ([email protected]) diversity, focusing on molecular markers, sampling strategy and morphological analyses. 1Botany Department, Smithsonian Institution, Washington, DC 20560-0166, United States; 2Biologia Marina, Universidad Autonoma de Baja California Sur, La Paz, BCS 23080, Mexico; 3Departamento de 1OR.12 Bioloxía Animal, Bioloxía Vexetal e Ecoloxía, RIPPLES OF THE PAST: HOW MUCH Universidade da Coruña, A Coruña 15001, Spain; ENDEMISM IS THERE IN SEAWEEDS? 4University of North Carolina Herbarium, University of North Carolina, North Carolina 27599-3280, Juliet Brodie ([email protected]) United States; 5Biologia Marina, Universidad Autonoma de Baja California Sur, La Paz, BCS 23080, Life Sciences, Natural History Museum, London Mexico; 6Institut de Systématique, Evolution, CR35EG, United Kingdom Biodiversité,, Muséum National d’Histoire Naturelle, 7 Since the application of molecular techniques in the Paris 75005, France; Dipartimento di Scienze della fi Vita e dell’Ambiente, Università Politecnica delle identi cation and systematics of the seaweeds (red, Marche - UNIVPM, Ancona 60131, Italy and 8Botany, green and brown macroalgae), it has become increasingly clear that there is considerably more diversity Smithsonian Institution, Washington, DC 20560-0166, fl United States than hitherto recognised that is not necessarily re ected in the morphology of these organisms. One of the ‘ ’ Lithophyllum congestum (subfamily Lithophylloideae) consequences of the recognition of cryptic diversity fi is reported as a common species forming algal ridges is a fundamental shift in de ning species concepts, around the Caribbean and it has been recorded as south with profound implications for understanding distribu- fi as Brazil. This species has been recently considered a tion, rarity and endemism. The de nition of what con- fi heterotypic synonym of L. stictaeforme, changing our stitutes an endemic, i.e. a species which is con ned to a circumscription of both species. In this study we ana- certain region, is reasonable, but asking how much lysed material of Lithophyllum congestum housed at endemism really exists in the seaweeds poses a number National Museum of Natural History (US) from the of questions. Using examples from my work on red, Caribbean, including countries as Cuba, Jamaica, green and brown seaweeds, I will explore the concept Puerto Rico, Virgin Islands, Caribbean British Islands of endemism in relation to taxonomic hierarchy, pat- and Martinique. In addition, we also studied the type terns of distribution, reproduction and dispersal, and material housed at The NTNU University Museum at consider whether there are any general principles we Norwegian University of Science and Technology can learn from these organisms. I will also consider (TRH). We aimed to elucidate the taxonomic status of how vital knowledge of endemism is in conservation Lithophyllum congestum complemented with data on policy and management of biodiversity. morphology and anatomy, molecular diversity and distribution. In addition, we compared our results obtained for L. congestum with Mediterranean collections identi- 1OR.13 fi ed as L. stictaeforme andalsowithrecordsofL. DEPAUPERATE ENVIRONMENTS: CRADLE kotschyanum, a species widely recorded from coral OF SPECIATION OR EVOLUTIONARY DEAD reefs. Our results show that i) coralline herbarium mate- ENDS? rial, even after 148 years in the case of type material or 37-49 years in the case of more recent Caribbean Ricardo T Pereyra ([email protected]) Keynote and Oral Papers 29

Marine Sciences, University of Gothenburg, Laguna, Canary Islands 38271, Spain; 8Phycology Strömstad 45296, Sweden Research Group and Center for Molecular Phylogenetics and Evolution, Ghent University, Ghent In terms of marine biodiversity, the Baltic Sea is a 9000, Belgium and 9UMR ENTROPIE, LabEx- depauperated mass of water relatively isolated from CORAIL, Institut de Recherche pour le Développement, the North Atlantic with a stable salinity gradient that Noumea B.P. A5, 98848, France poses a strong selective regime to any marine species willing to colonize it. The established populations of The use of gene sequence data has profoundly altered marine species that colonized it after the last glaciation our view on algal diversity on every taxonomic level. are at their ecological and geographical limits. Most spectacularly, sequence data unveiled the existence However, previous research in the Baltic Sea has of massive cryptic or pseudocryptic diversity at the shown adaptations to this environment that have pro- species level. Cryptic diversity also makes linking duced an extremely rapid speciation event in Fucus DNA-based lineages to existing taxa exceedingly diffi- seaweeds. Here, we used a population genomics cult,whichresultsinagrowingtendencytomovefroma approach with RAD-Seq to revisit this case and we formal algal taxonomy to a more informal system found that what was previously believed to be a single whereby clade-, specimen- or strain-based identifiers case of speciation might be a cryptic radiation instead. are used to communicate biological information. Despite no apparent physical barriers, the permanent Counteracting the emergence of parallel taxonomies salinity and temperature regimes, combined with the would require a better integration of historical collec- water circulation patterns in this region may effectively tions into modern taxonomic research. Here we explore isolate populations even at very short geographical the feasibility of linking taxonomic names, often distances, creating quick and large genetic differences described decades before DNA-based species identifica- among demes in many areas along the Baltic. tion became the norm in phycology, to clades in modern phylogenies. The brown algal genus Lobophora forms an excellent test case to explore the feasibility of such 1OR.14 efforts. Recent studies have demonstrated that the genus is far more diverse than traditionally assumed. For dec- MATCHING NAMES AND CLADES IN THE ades only a handful of species were recognized of which BROWN ALGAL GENUS LOBOPHORA L. variegata (J.V.Lamour.) Womersley ex E.C.Oliveira (DICTYOTALES, PHAEOPHYCEAE): AN was by far the most commonly reported. DNA-based EFFORT TO INTEGRATE TYPE SPECIMENS species delineation methodologies, however, indicate IN MODERN TAXONOMY that there may be at least over one 120 species. We Christophe Vieira1 ([email protected]), Olga reevaluated the identity of 17 taxa suspected to be repre- Camacho2 ([email protected]), Michael J sentative of Lobophora species by attempting DNA Wynne3 ([email protected]), Lydiane Mattio4 amplification of historical herbarium material as well ([email protected]), Robert J Anderson 5 as specimens recently collected from the type locality ([email protected]), John J Bolton6 (john. (epitypes). Our results indicate that exclusive reliance on [email protected]), Marta Sansón7 ([email protected]), information preserved in type specimensisproblematic. SofieD’hondt8 (sofi[email protected]), Suzanne For several species, either the type could not be traced or Fredericq2 ([email protected]), Claude Payri9 we did not get permission to extract DNA from types. ([email protected]) and Olivier De Clerck8 (olivier. Epitype material proved a more successful way forward, [email protected]) but this route often comes with a considerable degree of uncertainty, especially in tropical regions where the 1UMR ENTROPIE (IRD, UR, CNRS) LabEx-CORAIL, degree of sympatry among Lobophora lineages is some- Institut de Recherche pour le Développement, Noumea times considerable. B.P. A5, 98848, France; 2Department of Biology, University of Louisiana at Lafayette, Lafayette LA 3 0504-2451, United States; Department of Ecology and 1OR.15 Evolutionary Biology and Herbarium, University of Michigan, Ann Arbor MI 48109, United States; 4School BIODIVERSITY IN THE PLANKTONIC of Plant Biology, University of Western Australia, Perth DIATOM FAMILY CHAETOCEROTACEAE Crawley WA6919, Australia; 5Fisheries Research, Chetan Gaonkar1 ([email protected]), Roberta Department of Agriculture, Forestry and Fisheries, Piredda1 ([email protected]), Diana Sarno1 Roggebaai 8012, South Africa; 6Department of ([email protected]), Marina Montresor1 Biological Sciences and Marine Research Institute, ([email protected]), Adriana Zingone1 (zingone@szn. University of Cape Town, Cape Town 7701, South it), David G Mann2 ([email protected]), Carina Africa; 7Departamento de Botánica, Ecología y Lange3 ([email protected]) and Wiebe HCF Kooistra1 Fisiología Vegetal, Universidad de La Laguna, La ([email protected]) Keynote and Oral Papers 30

1Integrative Marine Ecology, Stazione Zoologica Goals of this study are a precise assessment of the Anton Dohrn, Naples 80121, Italy; 2Botany, Royal species diversity of Antarctic soil algae and to assess Botanic Garden Edinburgh, Edinburgh EH3 5LR, their functional traits by investigating defined sam- United Kingdom and 3Centro FONDAP-COPAS, pling plots along different temporal developmental Universidad de Concepción, Concepción n.a., Chile stages of soil after glacier retreat (chronosequences). Selected Antarctic soil algal species will be tested for Chaetocerotaceae is one of the most diverse marine possible endemism. The nuclear-encoded ITS2 rRNA planktonic diatom families. Its two genera, region is targeted to provide sufficient resolution for Chaetoceros and Bacteriastrum currently include species identification and comparisons with counter- over ca 230 and 15 taxonomically accepted species, parts from other continents. The ITS2 analyses were respectively. We set out to assess its diversity at the facilitated by easier PCR amplification when com- LTER station MareChiara in the Gulf of Naples pared to the plastid-encoded rbcL gene and by (GoN), Mediterranean Sea, at Roscoff, along the employing tools initially developed for fungal French Atlantic coast, and at Las Cruces in an upwel- sequences, e.g. for annotation. To enrich the clone ling zone on the central Chilean coast. Colony and libraries with sequences from algae, PCR primers to spore morphology, frustule ultrastructure as well as preferentially amplify rDNAs for certain algal groups nuclear LSU and SSU rDNA sequences have been were found inevitable because more general PCR gathered from ca 240 monoclonal strains. Results primer combinations underestimated the algal diver- showed 55 genetically distinct species, many of sity. The composition of the soil algae assemblages these being new to science. Phylogenies inferred varied considerably along the studied samples, which from the aligned sequences revealed several major represented different soil ages. A large number of clades of morphologically similar species. SSU algal clones could be identified with high similarities sequences in one of these clades contained up to 6 using BLAST sequence comparisons, especially for introns of ca. 140 base pairs each. In addition, many of the Klebsormidiophyceae, some Trebouxiophyceae the internal standard sequencing primers showed mis- and Chlorophyceae. For Klebsormidium, Interfilum matches in critical positions. V4 regions in the SSU and Desmococcus sequences were recovered with were used as taxonomic references and blasted against very high ITS2 similarities (99 and 100%) with an environmental V4-sequence dataset gathered from those of isolates from temperate regions. A consider- 40 plankton samples taken over three years at the able number of Ulvophyceae, difficult to recover from LTER station in the GoN. Results provide an unpre- soils using cultures, was revealed. For other algal cedented picture of the diversity and seasonal cycle in groups, e.g. the Xanthophyceae, species identification this species-rich family. was hampered because of a limited number of available reference sequences. Full reference sequences need to be established from cultures, i.e. from culture collections or establishing new isolates. The cloning/ 1OR.16 sequencing of long amplicons including conservative regions (5.8S, parts of SSU and LSU) enables the MICROALGAE COMMUNITIES IN assignment of algal clones where no closest ITS2 ANTARCTIC SOILS: CHANGES ALONG SOIL references are available as well as chimera check. DEVELOPMENTAL STAGES AND TESTING This approach also provides the reference sequences FOR GEOGRAPHICAL DISTRIBUTION for the development of group-specific primers for the Nataliya Rybalka1 ([email protected]), Jens shorter amplicons required for pyrosequencing. Boy2 ([email protected]), Heiko Nacke3 ([email protected]), Rolf 1OR.17 Daniel3 ([email protected]) and Thomas Friedl4 ([email protected]) ULVALES ON GERMAN BALTIC AND NORTH SEA COASTS: ABOUT CRYPTIC, ALIEN AND 1Experimental Phycology and Culture Collection of LOST SPECIES Algae (SAG); Genomic and Applied Microbiology, Sophie Steinhagen1 ([email protected]), Georg-August University Goettingen, Goettingen 1 2 Florian Weinberger ([email protected]) and 37073, Germany; Institute for Soil Sciences, Leibniz Rolf Karez2 ([email protected]) University Hannover, Hannover 30419, Germany; 3 Genomic and Applied Microbiology, Georg-August 1Marine Ecology, GEOMAR Helmholtz Centre for University Goettingen, Goettingen 37077, Germany 4 Ocean Research Kiel, Kiel 24105, Germany and and Experimental Phycology and Culture Collection 2State Agency for Agriculture, Environment and Rural of Algae (SAG), Georg-August University Goettingen, Areas, State Agency for Agriculture, Environment and Goettingen 37073, Germany Rural Areas, Flintbek 24220, Germany Keynote and Oral Papers 31

Green macroalgae of the order Ulvales are abundant history has been plagued by problems of cryptic diver- and often dominant in European marine and brackish sity, phenotypic plasticity and taxonomic misinterpre- shallow water environments and thus ecologically tations related to the importance of some important. Some of their representatives are character- morphological characters. Key tasks in current coral- istic foulers. Therefore Ulvales often get introduced line taxonomy are to clarify the extent of genetic varia- into new ecosystems where they have a high potential tion of individual species and link type specimens with of affecting algal diversity and ecosystem services. molecular phylogenetic clades. We examined three However, their morphology is often extremely vari- Mediterranean species of Lithophyllum (L. byssoides, able, which largely hampered their taxonomic identifi- L. incrustans, L. stictaeforme) using a combination of cation until recently. Cryptic or alien species are often molecular markers (cox2,3 spacer and psbA, rbcLand not recognized, while different phenotypes of the same 18S rDNA genes). The results unraveled different sce- species are in many cases regarded as distinct taxa. narios for the three species. Mediterranean L. byssoides Here we report the results of a survey on Ulvales represents a well-defined entity that should be sepa- biodiversity in the Baltic and North Sea areas of the rated at species level from Atlantic populations German state of Schleswig-Holstein and adjacent areas reported under the same name. Cox2,3 and psbA data that was based upon analyses of more than 700 samples showed an unexpectedly high variation, suggesting with different genetic barcoding markers (tufA, rbcL, limited dispersal in populations of this species. ITS). Molecular analyses based on sequences of rbcL, Lithophyllum incrustans is the type species of the ITS and tufA genes combined with morphological genus Lithophyllum and its characterization is therefore analyses revealed so far the presence of 20 different critically important. A partial rbcL sequence obtained species including 4 cryptic and 7 newly introduced taxa from the type material allowed to bridge the gap (thereof one potentially invasive) that were not known between molecular sequences and name-bearing type. from the area yet. Further, several species that were In light of this result we concluded that L. incrustans is until now estimated to occur in high abundance are common in subtidal habitats and may easily form rho- seemingly very rare or even absent. doliths. Intertidal crusts reported as L. incrustans both in the Mediterranean and in Atlantic Europe probably do not belong to this species. Lithophyllum stictae- 1OR.18 forme, as currently circumscribed on morphological basis, represents a complex of cryptic species for OLD AND NEW PROBLEMS IN THE which a taxonomic and nomenclatural reassessment is CIRCUMSCRIPTION OF MEDITERRANEAN necessary. Taken together, our results indicate that the LITHOPHYLLUM SPECIES OF genetic diversity of Mediterranean coralline algae is (CORALLINALES, RHODOPHYTA) probably much higher than currently believed and Laura Pezzolesi1 ([email protected]), sequences from type specimens will be essential to Christian Russo2 ([email protected]), Jazmin J unambiguously identify many species. Hernandez-Kantun3 ([email protected]), Annalisa Falace4 ([email protected]), Sara Kaleb4 (skaleb@units. it), Viviana Peña5 ([email protected]), Line Le Gall6 1OR.19 ([email protected]), Carlo Cerrano2 (c.cerra- 2 TAXONOMIC REVISION OF [email protected]) and Fabio Rindi ([email protected]) PAPENFUSSIELLA SPECIES IN THE 1Dipartimento di Scienze Biologiche, Geologiche e NORTHERN HEMISPHERE Ambientali, Università di Bologna, Ravenna 48123, Hiroshi Kawai1 ([email protected]), Kohei Italy; 2Dipartimento di Scienze della Vita e Miyoshi2 ([email protected]) and Takeaki dell’Ambiente, Università Politecnica delle Marche, Hanyuda3 ([email protected]) Ancona 60131, Italy; 3Department of Botany, Smithsonian Institution, Washington DC 20560, United 1Research Center for Inland Seas, Kobe University, States; 4Dipartimento di Scienze della Vita, Università Kobe 657-8501, Japan; 2Graduate School of Science, di Trieste, Trieste 34127, Italy; 5Facultade de Ciencias, Kobe University, Kobe 657-8501, Japan and 3Research Universidade da Coruña, A Coruña 15071, Spain and Institute for Inland Seas, Kobe University, Kobe 6Equipe Exploration, Espèces et Evolution, Muséum 657-8501, Japan National d’Histoire Naturelle, Paris 75005, France Molecular phylogeny of Papenfussiella species using Coralline algae are among the most common seaweeds mitochondrial cox3 and chloroplast rbcL-rbcS DNA in benthic habitats worldwide, as well as one of the sequences revealed considerable species diversity in most species-diverse groups. Unfortunately, they are the genus. Although only P. kuromo is currently also among the most problematic in terms of species recognized in Japan, the specimens referable to circumscription and characterization. Their taxonomic Papenfussiella collected in Japan formed four distinct Keynote and Oral Papers 32 clades (clade-1, -2, -3 and -4) with high statistical lections and type specimens) and molecular data support. Specimens of clade-1 corresponded to P. (using the plastid RUBISCO gene rbcL and the kuromo, because the sequences as well as the mitochondrial barcode region of the gene cox1). morphology agreed well with those of the lectotype Only one species (B. macrosporum Montagne) was specimen. Specimens corresponding to clade-2 were recognized in the section based on the currently similar to P. k uro mo in gross morphology, but were applied morphological diagnostic characters: distinguished anatomically by the presence of a carpogonial branches long (≥ 6 cells and ≥ 65 µm in subcortical layer. Clade-3 consisted of the syntype length); distal involucral filaments short (1 cell), specimens of P. ku rom o f. densa Inagaki, having nar- forming a crown around the carpogonium; large rower thalli with denser branches, and we propose to carposporangia (≥ 21 x 19 µm). Two species were treat this taxon as an independent species. Clade-4 proposed as synonyms: B. equisetifolium Montagne consisted of specimens from Eastern Hokkaido. They and B. hypogynum Kumano & Ratasabapathy. formed a clade with P. callitricha but were genetically Genetic variation within this species was highly distinct. In addition, preliminary study of Southern variable: 0-69 base pairs (bp), 0-10.4% for rbcL and Hemisphere Papenfussiella species also suggested the 0-85 bp, 0–6.6% for cox1. Five groups were recog- occurrence of several more cryptic species in the genus. nized within B. macrosporum applying two single- locus DNA-based species delimitation techniques. All groups have clear-cut genetic limits and some 1OR.20 have a defined geographic distribution. The five REVISION OF THE SECTION MACROSPORA groups were recognized as cryptic species but they KUMANO OF THE GENUS are not formally proposed as distinct species. These BATRACHOSPERMUM (RHODOPHYTA, groups occurred in tropical and subtropical regions of BATRACHOSPERMALES) the world and were particularly widespread in North and South America. Molecular phylogenetic analyses Orlando Necchi Jr ([email protected]) and showed Macrospora as a well-supported clade within Auro Silva Garcia Jr ([email protected]) the Batrachospermales. An additional morphological Zoology and Botany, São Paulo State University, character (post-fertilization carpogonial branches with S. Jose Rio Preto 15054-000, Brazil enlarged pit connections) was evidenced as a new morphological character to support the circumscrip- A revision of the section Macrospora was carried out tion of the section. We propose the raising of the based on morphological analysis (including new col- section to the genus level. Keynote and Oral Papers 33

2. Shedding new light on photosynthesis and its role in global biogeochemistry

2KN.1 Diatoms are a widespread and ecologically important MIXOTROPHS IN AQUATIC ECOSYSTEMS: group of heterokont algae that contribute ca. 20% to PRIMARY PRODUCERS OR CONSUMERS? global productivity. Previous work has shown that regulation of their key Calvin cycle enzymes differs from Susanne Wilken ([email protected]) that of the Plantae, and that in crude extracts, glyceral- dehyde-3-phosphate dehydrogenase (GAPDH), an Molecular Microbial Ecology, Monterey Bay enzyme involved in this CO2 assimilation pathway can Aquarium Research Institute, Moss Landing be inhibited by NADPH under oxidizing conditions. CA-95039, United States The freshwater diatom, Asterionella formosa,wasstu- died using enzyme kinetics, chromatography, surface Microalgae are well recognized as key players in the plasmon resonance, mass spectrometry and sequence carbon cycle by contributing about half of global analysis to determine the mechanism behind this primary production. However, next to carbon GAPDH inhibition. In this diatom, GAPDH interacted fi xation many microalgae are also capable of hetero- with ferredoxin–nicotinamide adenine dinucleotide trophic nutrition by feeding on other microorganisms. phosphate (NADP) reductase (FNR) from the primary These mixotrophs are increasingly recognized as phase of photosynthesis, and the small chloroplast pro- important components of microbial food webs. Due tein, CP12. Sequences of co-purified GAPDH and FNR to their nutritional versatility the net contribution of were highly homologous with published sequences. mixotrophs to primary production and ecosystem However, the widespread ternary complex among respiration is variable and dependent on environmen- GAPDH, phosphoribulokinase (PRK) and CP12 was tal conditions. While physiological experiments using absent. Activity measurements under oxidizing condi- the chrysophytes Ochromonas spp. indicate a tight tions showed that NADPH can inhibit GAPDH-CP12 in integration of the photosynthetic and heterotrophic the presence of FNR, explaining the earlier observed metabolism with a tendency towards photoheterotro- inhibition within crude extracts. The absence of the phy, both components can be affected differentially by ternary GAPDH-CP12-PRK complex may be due to environmental factors. For example increasing tem- the absence of two cysteine residues at position C243 peratures cause a shift in the nutritional strategy and 249 (numbered from the alga, Chlamydomonas towards heterotrophy. Increasing rates of prey inges- reinhardtii on diatom PRK. Diatom plastids have a tion have also been observed in a climate change distinctive metabolism, including the lack of the oxida- scenario for a natural phytoplankton community tive pentose phosphate pathway, and so cannot produce from a temperate lake. Such shifts in the nutrition of NADPH in the dark. The observed down-regulation of mixotrophs will affect microbial population dynamics GAPDH in the dark may allow NADPH to be rerouted and modulate the cycling of both carbon and nutrients. towards other reductive processes contributing to their ecological success. However this GAPDH regulation is 2KN.2 absent in other diatoms such as Thalassiosira pseudo- BIODIVERSITY OF GAPDH REGULATION IN nana, opening questions about evolution and ecology. MICROALGAE 1 Brigitte Gontero ([email protected]), Stephen 2KN.3 C Maberly2 ([email protected]), Malika Mekhalfi3 (mmekhalfi@imm.cnrs.fr), Carine Puppo3 (cpuppo@ SYSTEMS-WIDE ANALYSIS OF imm.cnrs;fr), Regine Lebrun4 ([email protected]) ACCLIMATION RESPONSES TO LONG- and Pascal Mansuelle5 ([email protected]) TERM HEAT STRESS AND RECOVERY IN THE PHOTOSYNTHETIC MODEL CHLAMYDOMONAS 1BIP, AMU- CNRS, Marseille 13009, France; 2Lake ORGANISM REINHARDTII Ecosystems Group, NERC-CEH, Lancaster LA14AP, 3 United Kingdom; BIP, Marseille 13009, France; Timo Mühlhaus1 ([email protected]), 4 Proteomic platform, Marseille 13009, France and Dorothea Hemme1 ([email protected]), 5 Proteomic Platform, Marseille 13008, France Daniel Veyel1 ([email protected]), Frederik Keynote and Oral Papers 34

Sommer1 ([email protected]), Jessica 2OR.1 Jüppner2 ([email protected]), USING FAST REPETITION RATE Ann-Katrin Unger3 ([email protected]), FLUOROMETRY TO ESTIMATE PSII Stefan Geimer3 ([email protected]), ELECTRON FLUX PER UNIT VOLUME: A Patrick Giavalisco2 ([email protected]. PURELY OPTICAL METHOD FOR de) and Michael Schroda1 ([email protected]) ESTIMATING GPP BY PHYTOPLANKTON? 1Molecular Biotechnology and Systems Biology, TU Kevin Oxborough1 ([email protected]), Kaiserslautern, Kaiserslautern 67663, Germany; Mark Moore2 ([email protected]), David J 2Molecular Physiology, Max-Planck-Institut für Suggett3 ([email protected]) and Richard Molekulare Pflanzenphysiologie, Potsdam-Golm 14476, Geider4 ([email protected]) Germany and 3Zellbiologie/Elektronenmikroskopie, Universität Bayreuth, Bayreuth 95440, Germany 1Research and Development, CTG Ltd, West Molesey KT82QZ,UnitedKingdom;2Ocean and Earth Science, Occasions of extreme heat stress HS may severely University of Southampton, Southampton SO14 3ZH, reduce plant growth. Therefore, a comprehensive United Kingdom; 3C3 group, UTS, Sydney NSW 2007, understanding of HS as a consequence of global Australia and 4School of Biological Sciences, University warming is of significant interest for agriculture and of Essex, Colchester CO4 3SQ, United Kingdom aquaculture industry. In a system-wide analysis, using the unicellular green alga Chlamydomonas reinhardtii Obtaining accurate estimates of GPP by phytoplank- as a model system, acclimation responses to long-term ton in highly dynamic environments, such as complex HS were studied in a time-resolved manner and under coastal seas, continues to present a major challenge to controlled conditions. For this, we shifted cells from oceanographers. Although Fast Repetition Rate 25 to 42°C for 24 h and back to 25°C for ≥8h and Fluorometry (FRRF) has long been used for in situ monitored changes in abundances of proteins, meta- estimation of GPP, the requirement for an independent bolites and lipids and changes of many cytological method to determine the concentration of functional and physiological parameters. The data indicate that photosystem II reaction centres ([RCII]) has limited acclimation of Chlamydomonas to long-term HS is the application of this method. A new approach to the coordinated and implemented as sub-responses that analysis of FRRF data has allowed for estimation of can be temporally and functionally connected and [RCII] from dark FRR data alone (Oxborough et al. were therefore termed “response elements”. These 2012). The same approach to the analysis of FRR data are executed in order to prevent irreversible damage has also led to development of an ‘absorption algo- and to maintain cellular homeostasis, thereby allow- rithm’, which can be used to generate wavelength- ing cells to acclimate to HS and to survive. Five specific PSII absorption coefficients (aLHII values, response elements could be distinguished: (i) the with units of m-1) from dark FRR measurements. arresting of DNA replication and cell division; (ii) Importantly, the product of aLHII and PSII photoche- catabolism of larger molecules to generate compounds mical efficiency under ambient light (which can also with roles in stress protection; (iii) accumulation of be estimated from FRR data, through the Fq’/Fm’ molecular chaperones to restore protein homeostasis parameter) provides an estimate of GPP which does together with compatible solutes; (iv) redirection of not require determination of [RCII] to estimate GPP photosynthetic energy and reducing power from the and provides a greatly improved signal to noise ratio Calvin cycle to the de novo synthesis of saturated fatty under high photon irradiance. Since all parameters acids to replace polyunsaturated ones in membrane required for application of the absorption algorithm lipids, which are deposited in lipid bodies; and (v) are derived from FRR data, this approach to the esti- when sinks for photosynthetic energy and reducing mation of GPP can be applied on wide spatial and power are depleted, resumption of Calvin cycle temporal scales and can realistically be considered as a activity associated with increased photorespiration, viable alternative to photosynthetron-based measure- accumulation of reactive oxygen species scaven- ments of 14C uptake. This talk will cover recent gers, and throttling of linear electron flow by developments and outstanding issues related to appli- antenna uncoupling. During recovery from HS, cation of the absorption algorithm, including the pro- cells appear to focus on processes allowing rapid cessing of data to minimise the error generated by resumption of growth rather than restoring pre-HS fluorescence from sources other than functional RCII conditions. (baseline fluorescence, F¬b). Keynote and Oral Papers 35

2OR.2 (PP) varies within marine ecosystems. However, major uncertainty still exists in how PP estimates determined HIGH RESOLUTION FRRF MEASUREMENTS using fluorometry (absolute electron transfer rate, ETR) TO MEASURE NET AND GROSS PRIMARY scale to corresponding rates of carbon (C)-uptake. To PRODUCTION address this gap, studies have simultaneously measured Jacco C Kromkamp1 ([email protected]), ETR and C-uptake to derive the so-called “electron Greg Silsbe2 ([email protected]) and Catharina J.M requirement for carbon fixation” (e:C), and commonly Philippart3 ([email protected]) observed that this conversion factor varies according to the dominant phytoplankton taxa present under steady- 1 Marine Biology, NIOZ, Yerseke Korringaweg 7, state growth. However, no study has yet resolved to 2 Netherlands; Dept. of Botany and Plant Pathology, what extent e:C potentially varies when systems are Oregon State University, Corvallis OR 97331, United perturbed, particularly when nutrient availability 3 States and Marine Ecology, NIOZ, ‘t Horntje (Texel) impacts upon phytoplankton physiology and/or commu- 1797 SZ, Netherlands nity structure. Therefore, we performed fully multi-factorial macronutrient bioassays (N, P and Si) upon natural In this presentation, we will show how we can use Fast phytoplankton communities collected from a coastal Repetition Rate Fluorometry (FRRF) as an alternative reference station (Port Hacking, NSW) near the means to measure primary production, and how we can Eastern Australian Current during summer, when automate the technique, so that it can be used autono- macronutrients are known to be limiting. Our results fi mously on ships or on xed stations. Recent develop- consistently demonstrated that e:C responded strongly ments now allow to measure absolute rates of electron to N addition, either in isolation or in combination with transport and obtain concentrations of PSII reaction P and/or Si. In the control bottles, e:C typically ranged fl − centres. We will brie y explain this, give examples of between 10-12mol e [mol C] 1, values which are higher measurement and show high resolution time measure- than expected for a large range of phytoplankton when ments obtained at several locations. Comparisons with under steady-state growth, but decreased threefold (3-4 14C-measurements demonstrates the annual variability mol e [mol C]−1) and close to the theoretical minimum fi in electron requirements for C- xation at several sam- for the N treatment. This influence of N for two of the pling stations in Dutch marine waters and we will show bioassays (December, February), was strongly driven by how we can obtain daily and annual rates of primary a taxonomic shift (also reflectedbyanincreaseinthe production. Lastly, we will show, using cultures, how the >10µm size-fraction), whilst the third bioassay (January) fi electron requirement for C- xation changes going from was conducted immediately following a transient gross to net photosynthesis. bloom, resulting in a strong physiological response of the existing population. Our unique approach therefore fl 2OR.3 demonstrates that e:C can be in uenced by both taxonomic and physiological adjustments to phytoplankton NITROGEN AVAILABILITY DRIVES communities, but both driven by an underlying limita- VARIABILITY OF THE ELECTRON tion of N availability. REQUIREMENT FOR CARBON FIXATION IN COASTAL PHYTOPLANKTON COMMUNITIES 2OR.4 David J Hughes1 ([email protected]), Martina 1 1 EFFECTS OF INCREASED CO AND IRON ADoblin ([email protected]), Peter J Ralph 2 AVAILABILITY ON THE MECHANISMS OF ([email protected]), Virginie van Dongen- 1 CARBON ASSIMILATION AND Vogels ([email protected]), Tim 2 CALCIFICATION DURING A BLOOM OF THE Ingleton ([email protected])and 1 COCCOLITHOPHORE EMILIANIA HUXLEYI David J Suggett ([email protected]) M Rosario Lorenzo1 ([email protected]), Concepcion 1Plant Functional Biology and Climate Change Iñiguez1 ([email protected]), Jorun K Egge2 (Jorun. Cluster, University of Technology Sydney, Australia, [email protected]), Aud Larsen2 ([email protected]), University of Technology Sydney, Sydney 2007, Candela García-Gómez1 ([email protected]) and Australia and 2Waters and Coastal Science, New Maria Segovia1 ([email protected]) South Wales Department Office of Environment and Heritage, Department of Premier and Cabinet, 1Department of Ecology, University of Malaga, Sydney 2001, Australia Malaga 29071, Spain and 2Department of Biology, University of Bergen, Bergen 5020, Norway Active chlorophyll fluorescence induction techniques have the potential to revolutionise our understanding of A mesocosm experiment was carried out in the the nature and extent with which primary productivity Raunefjord (Bergen, Norway) to investigate the Keynote and Oral Papers 36 interactive effects of increased CO2 and iron availability Plocamium cartilagineum across a range of atmospheric during a bloom of the coccolithophore Emiliania hux- CO2 concentrations (385-1000 μatm) spanning recent leyi. The seawater carbonate system of half of the concentrations to the high end predictions for 2100 mesocosms was manipulated to achieve CO2 levels (IPCC). U. lactuca is a fast growing species with a corresponding to predicted future conditions (900 complex CCM that uses HCO3- to saturate photosynth- ppmV) as compared to present ambient conditions esis with inorganic carbon. P. cartilagineum depends on (390 ppmV). Dissolved Fe concentrations were also the diffusive uptake of CO2 that potentially leaves manipulated by addition of the siderophore desferriox- photosynthesis carbon limited. To test for responses to amine B (DFB) promoting an increase in dissolved iron OA in these species that differ in their primary carbon (dFe). The experiment consisted of a multifactorial source and carbon acquisition mechanism we cultured design with combinations of both levels (high and each alga for 21 days at various pCO2 concentrations. A ambient) of CO2 and dFe. Primary production rates pH drift experiment was then performed to determine were measured by in-vitro incubations based on the relative activity of the CCMs if present. In both 14 C-fixation and particulate calcium was measured by cases, growth rate was enhanced by intermediate pCO2 wavelength dispersive X-ray fluorescence (WXRF). relative to recent and very high pCO2. The CCM of Ulva Primary productivity (PP) was enhanced as a direct was similarly affected by pCO2. P. cartilagineum consequence of the E. huxleyi bloom and the Ca/POC showed evidence of external carbonic anyhydrase activ- ratio presented the highest values and a significant linear ity and declining efficiency of inorganic uptake as pCO2 regression in the same treatment as PP during the increased. The results indicate that CCMs are regulated bloom. PIC/POC ratios supported such data. in response to ocean acidification. This coordinates with Maximum molar [POC]:[PON] ratios were observed findings that growth increases in Ulva as pCO2 at the end of the experiment; thus the treatments had increases, but indicates an upper threshold of this significant effects on C:N ratios. The isotope disequili- benefit. brium assay was used to determine the relative fraction of HCO3-andCO2 uptake. The fraction of HCO3- 2OR.6 uptake obtained for all treatments indicated a high rate within the community over time. The highest rate of LIMITS TO THE POSITIVE EFFECT OF OCEAN ACIDIFICATION ON MACROALGAL extracellular CO2:HCO3- interconversion (α), as a measure of extracellular carbonic anhydrase activity (eCA) PRODUCTION changed as the community shifted. The relevance of Janet E Kübler ([email protected]), Anne-Marin these results within the global change scenario will be Nisumaa ([email protected]) and Steven R discussed. Dudgeon ([email protected])

Biology Department, California State University at 2OR.5 Northridge, Northridge 91330-8303, United States THE ROLE OF CARBON CONCENTRATING About one third of macroalgal species lack any carbon MECHANISMS IN MACROALGAL concentrating mechanism (CCM), which prevents car- RESPONSES TO OCEAN ACIDIFICATION bon limitation under air equilibrium in other seaweed Samuel R Scoma ([email protected]), species. It is predicted that those species lacking CCM’s Anne-Marin Nisumaa ([email protected]) and will benefit from ongoing ocean acidificationintermsof Janet E Kübler ([email protected]) primary productivity and growth. The absolute sizes and pattern of those benefits are not known. Here, we Biology Department, California State University, compare the results of a model based on composite data Northridge, Northridge 91330-8303, United States from the literature, with a growth experiment using Plocamium cartilagineum, a broadly distributed rhodo- The majority of fleshy macroalgae, across all groups, phyte species lacking a carbon concentrating mechan- contain carbon-concentrating mechanisms (CCMs) that ism and hypothesized to be carbon limited under current facilitate use of dissolved inorganic carbon. Rising conditions. We grew P. c arti lag in eu m,at15and20°Cin atmospheric CO2 concentrations and the resulting shift seawater aerated with a total of 53 different pCO2s in seawater carbonate chemistry and ocean acidification (from 344 to 1053µatm), in 8 multi-week trials over (OA) may have varying effects on algae depending on 12 months. We measured growth and photosynthetic their mode of inorganic carbon concentration, if any, and rates. A linear mixed model analysis was used to parti- its regulation. Energetic costs of these carbon uptake tion the effect sizes of drivers of variation in the experi- mechanisms may change with rising pCO2 and may ment. The growth rates and maximum photosynthetic explain the difference in effects of OA on growth and rates responded nonlinearly to OA, increasing with photosynthesis. We investigated the relative activity of elevated pCO2 from recent atmospheric level to up CCMsinthegreenalgaUlva lactuca andtheredalga 450µatm and decreasing at higher pCO2.Light Keynote and Oral Papers 37 harvesting efficiency was unaffected by pCO2 and the pattern of response. The size of the effect of pCO2 on inversely related to temperature. We were able to com- growth rate in the experiment was greater than the effect pare the results of the growth experiment directly to the predicted by the model. These results predict that the model based on the additive effects of temperature and benefit of OA for macroalgal growth may disappear as pCO2 on photosynthetic rates, finding concordance of ocean acidification continues through this century. Keynote and Oral Papers 38

3. Algal Lipids not just for burning

3KN.1 3KN.2 METABOLIC ENGINEERING OF DIATOMS INDUSTRIAL POTENTIAL OF MICROALGAE FOR THE ENHANCED PRODUCTION OF FOR APPLICATIONS IN FOOD, FEED AND HIGH VALUE LIPIDS SPECIALTY CHEMICALS Mary Hamilton1 ([email protected]), Rene H Wijffels ([email protected]) Richard P Haslam2 ([email protected]. uk), Olga Sayanova2 ([email protected]. Bioprocess Engineering, Wageningen University, uk) and Johnathan A Napier2 (johnathan.napier Wageningen 6700AA, Netherlands @rothamsted.ac.uk) The objective of my research is to reduce the cost 1N/A, Rothamsted Research, Herts AL5 2JQ, United of algal production and biorefinery and to develop Kingdom and 2n/a, Rothamsted Research, London the basis of an industrial production process. AL5 2JQ, United Kingdom Microalgae are considered as one of the most promising feedstocks for a sustainable supply of com- It is now well established that omega-3 long chain modities and specialties for both food and non-food polyunsaturated fatty acids (LC- PUFAs), especially products. For the industrialization of algal technol- eicosapentaenoic acid (EPA; 20:5Δ5,8,11,14,17) and ogy the following approach is important:- Whole docosahexaenoic acid (DHA; 22:6Δ4,7,10,13,16,19) chain approach: integrating the full production are essential constituents of human nutrition. chain.- Multidisciplinary approach: different exper- Although marine fish are the main dietary source tise expertises need to be integrated.- Bridge from of EPA and DHA, the depletion of fish stocks and fundamental research to applications: technologies pollution of the marine environment indicate an need to be developed both on a lab- and pilot- scale urgent need for an alternative and sustainable and move from initial idea to the production pro- source of omega-3 LC-PUFAs. Marine microorgan- cesses that deliver competitive and innovative pro- isms are the primary producers of omega-3 LC- ducts to our industrial partners. Our present research PUFAs in the aquatic food chain and EPA- and program is driven by a techno-economic analysis. DHA–rich microalgae have been demonstrated to Our first techno-economic analysis was published in be a promising alternative source to fish oils. 2011. Based on literature data we calculated that the However, commercial production of high value pro- cost of biomass production was nearly 6 €/kg dry ducts like omega-3 LC-PUFAs is expensive and matter if performed at a 100 ha scale and we also presents a substantial technological challenge needed to reduce production costs 10 times. The for upscaling. There is, however, an increasing research agenda for the 15 years roadmap was interest in the metabolic engineering of microalgae determined by the techno-economic analysis.The to enhance the accumulation of these important techno economic analysis has been revisited in fatty acids. Phaeodactylum tricornutum is a unicel- 2014. For biomass production costs experimental lular diatom, which accumulates up to 30% EPA results from AlgaePARC pilot facility were used. but only traces of DHA and which is considered a In addition, costs for biorefinery have been good source for the industrial production of EPA. included. Biorefinery and production costs were We have engineered P. tricornutum to accumulate combined and compared to the market values. elevated levels of DHA by overexpressing hetero- Market values resulted from different combinations logous genes encoding enzyme activities of the of end products from microalgae and cyanobacteria. omega-3 LC-PUFA biosynthetic pathway. Our data demonstrate the efficient channelling of DHA into neutral lipids with several novel triacylglycerol spe- 3OR.1 cies being detected in the transgenic strains. This PLASTICITY OF FATTYACID PROFILES AND study provides novel evidence for the potential of CONTENTS IN SEAWEEDS using metabolic engineering to optimize omega-3 Matthias J Schmid ([email protected]), LC-PUFAs content in transgenic microalgae and Freddy Guihéneuf ([email protected]) also provides insights into the flux of these fatty and Dagmar B Stengel ([email protected]) acids in diatoms. Keynote and Oral Papers 39

Botany and Plant Sciences, School of Natural The effect of Cu limitation on the lipid composition of Sciences, Ryan Institute, National University of the diatoms Pseudo-nitzschia delicatissima was assessed Ireland Galway, Galway 1, Ireland in ultra-clean conditions in Aquil medium, starved or not in copper (0 or 20 nmol.L−1 of total Cu). In both condi- Seaweeds have been identified as a potential alternative tions, detailed lipid composition (membrane and reserve source of polyunsaturated fatty acids (PUFA). The fatty lipid fatty acid (FA) and lipid class compositions; sterol acid profile of macroalgae is particularly rich in omega-3 composition) was also analyzed, quantitatively and qua- fatty acids, e.g. EPA (20:5 n-3) and SDA (18:4 n-3). The litatively; by high performance thin layer chromatogra- western diet is deficient in the intake of omega-3 fatty phy (HPTLC) and gaz chromatography (GC). To acids and a dietary supplementation of these compounds understand the significance of the lipid modifications, can be a powerful measure in the prevention of chronic some cell physiological parameters were monitored diseases. As part of NutraMara, Ireland’sMarine using flow cytometry (growth rate, mortality, morphol- Functional Foods Initiative, we assess and evaluate the ogy, chlorophyll content, cell cycle, esterase activity potential of marine-origin bioactive compounds as com- and total lipid content) and using a pulse-amplitude ponents in Functional Foods and as food ingredients. modulation fluorometer (quantum yield (QY)). Cu star- One focus of the project has been to achieve a better vation led to marked modifications of cell lipid com- understanding of the dynamics and variability of bioac- position. Total lipid content was 3-fold higher in Cu- tives in seaweeds in natural and under controlled labora- starved cells than in replete ones. This was principally tory conditions. A major interest here is the plasticity of attributable to higher amounts of triglycerides, which fatty acids in seaweeds. It is understood that the lipid were the main reserve lipids. Qualitative composition profile of seaweeds can vary strongly according to of membrane lipids was also profoundly modified, with environmental conditions in their habitat. In order to an inversion of the relative proportions of cholesterol achieve algal biomass which is stable and optimised and 24-methylene cholesterol, and a 70%-increase of with regard to chemical composition for specific uses, digalactosyl diacylglycerol/monogalactosyl diacylgly- a better understanding of such dynamics is needed. cerol ratio. In the meantime, Cu starvation led to impor- Here, an overview of variability of fatty acids in selected tant physiological changes. Cell cycle was blocked in brown and red macroalgae of commercial interest G2 phase, which led to a 34%-reduction of cell growth (Ascophyllum nodosum, Laminaria digitata, Fucus ser- rate. Observed increased triglyceride cell content could ratus and Palmaria palmata) in Ireland will be pre- thus reflect energy storage in absence of cell division. sented. The data suggest distinct species-specific Cu starvation also induced a slight QY decrease (-9%), seasonal and spatial patterns. Further detailed analysis compensated by a higher chlorophyll content, which of different polar and neutral lipid classes within F. allowed maintaining cell energy acquisition. Observed serratus and P. palmata revealed species- and habitat- re-arrangements of P. delicatissima membrane lipids specific responses to environmental changes with sig- could partly explain why Cu starvation only induced a nificant implications for commercial applications. The slight QY decrease. It would allow maintaining optimal results may support industry in the selection of target micro-environment for membrane proteins, some of species and optimal sampling times and locations in them playing important roles in photosynthesis, and order to apply high-value algal biomass as a source for thus their optimal activity. valuable bioactive food compounds. 3OR.3 LINKAGE BETWEEN PHOTOSYNTHESIS 3OR.2 AND NITROGEN METABOLISM ON THE ACCUMULATION OF LIPIDS IN LIPID COMPOSITION MODIFICATIONS OF MICROALGAE PSEUDO-NITZSCHIA THE MARINE DIATOM 1 DELICATISSIMA Maria Huete-Ortega (m.hueteortega@sheffield.ac. UNDER COPPER 2 fi STARVATION uk), Matt P Johnson (matt.johnson@shef eld.ac.uk), Jim Gilmour2 (d.j.gilmour@sheffield.ac.uk), Fabienne Le Grand ([email protected]), Katarzyna Okurowska1 (k.okurowska@sheffield.ac. Aurélie Lelong ([email protected]), Marc Long uk) and Seetharaman Vaidyanathan1 (s.vaidya- ([email protected]), Hélène Hégaret (Helene. nathan@sheffield.ac.uk) [email protected]), Eva Bucciarelli (Eva. [email protected]) and Philippe Soudant 1Chemical and Biological Engineering, the University ([email protected]) of Sheffield, Sheffield S1 3JD, United Kingdom and 2Molecular Biology and Biotechnology, The LEMAR UMR 6539, IUEM - University of Brest, University of Sheffield, Sheffield S10 2TN, United Plouzané 29280, France Kingdom Keynote and Oral Papers 40

Photosynthetic microalgae have a great potential for PUFAChain aims at substantiating the industrial devel- biofuel production. In microalgae, both growth and opment of sustainable high-value products from micro- lipid production are a physiological trade-off, result- algae, i.e. mainly the omega-3 polyunsaturated fatty ing from balancing the resource and energy allocation acids DHA and EPA. Two bioresources, the SAG within the cells amongst the anabolic and catabolic (Göttingen University) and the CCCryo (Fraunhofer) pathways. In this sense, lipid production in microalgae culture collections, will provide optimization through has been suggested to act as a sink of the chemical screening of algal strains from temperate and the Polar energy and reductant power resulting from photo- Regions. The cold-adapted strains may sustain a suffi- synthesis when cell growth is arrested. Therefore, in cient PUFA out door production in Middle Europe in order to better understand the lipid production path- the colder season. At SAG, those strains, which were way, the linkage between both photosynthesis and preselected through a previously published large qua- nitrogen assimilation was investigated in the present litative screening for lipid profiles and appear promis- research. Two taxonomically different species ing for photobioreactor technology, are further tested (Nannochloropsis oceanica and Phaeodactylum tri- for their optimal PUFA yield. This includes many cornutum) of microalgae were grown in batch cultures strains not exploited so far as well as already well- at high light intensity and under different nitrogen known EPA/DHA producers. So far, the EPA, DHA sources (Nitrate, Nitrogen free and Ammonia). and ARA content in dry algal biomass was quantified Changes in the growth rate, biochemical composition for more than 100 strains, representing almost all and photophysiology by Chlorophyll a fluorescence classes of eukaryotic algae with emphasize on methodology were examined to establish trade-offs in Chlorophyta, Eustigmatophyceae (Stramenopiles) and their physiological response towards biofuel produc- Dinophyta. PUFA content varied greatly within a cer- tion. Both species presented a significant decrease in tain group among different species. EPA ranged from growth rate in the Nitrogen free treatment with respect 0.04% to 4.6% of dry mass and DHA from 0.03 to to the Nitrate and Ammonia, matching the decrease in 1.8%. There were even cases where the PUFA content Chlorophyll a and protein contents. Conversely, total varied between different strains within the same spe- fatty acids were higher in the Nitrogen free treatment, cies. Almost all strains contained ARA, which, how- but similar to the content obtained in the Ammonia ever, is undesired due to its inflammatory activity in treatment. In both species, Chlorophyll a fluorescent human organism. However, a selection of strains with measurements indicated the photodamage of the high EPA and/or DHA content and no or low ARA Photosystem II in the Nitrogen free treatment (signifi- content was recovered and will be further proceeded to cant lower maximum quantum yields and photosyn- next steps of PUFA yield optimization, upscaling and thetic efficiencies), while marked differences in the extraction following the biorefinery concept. amount of phototochemical (qP) and non-photochemical quenching (NPQ) were found between them. The role of the NPQ on lipid production was further investigated. 3OR.5 LIPID ACCUMULATION IN 3OR.4 PHAEODACTYLUM TRICORNUTUM OBTAINED BY A MUTATION-SELECTION THE EUROPEAN PUFACHAIN PROJECT PROCEDURE (FP7) - A VALUE CHAIN FROM ALGAL 1 BIOMASS TO LIPID-BASED PRODUCTS Judith Rumin ([email protected]), Bruno 1 1 Saint-Jean ([email protected]), Catherine Anastasiia Kryvenda ([email protected]), Michael 1 2 3 Rouxel ([email protected]), Jean-Paul Stehr ([email protected]), Thomas Leya 2 1 Cadoret ([email protected]) and Gaël ([email protected]), Birgit Olberg Bougaran1 ([email protected]) ([email protected]) and Thomas Friedl1 (tfriedl@ uni-goettingen.de) 1Physiology and Biotechnology of Algae laboratory, 2 1 IFREMER, Nantes 44300, France and GREENSEA, Experimental Phycology and Culture Collection of Mèze 34140, France Algae (SAG), Albrecht-von-Haller Institute for Plant Sciences, Georg-August-University of Göttingen, Microalgae are currently emerging as one of the most 2 Goettingen 37073, Germany; CREMER OLEO promising alternative sources for the next generation GmbH & Co. KG, Witten 58453, Germany and of food, feed and renewable energy in the form of 3 Fraunhofer Institute for Cell Therapy and biofuel. Major challenges for the development of Immunology, Branch Bioanalytics and Bioprocesses, this resource are to select lipid-rich strains using Extremophile Research & Biobank CCCryo,, high-throughput staining for neutral lipid content in Fraunhofer IZI-BB, Potsdam-Golm 14476, Germany microalgae species. Species domestication strategies Keynote and Oral Papers 41 including random mutation and selection procedure is system. Building upon advances in technology, input a powerful tool to genetically modify organisms and from the user community, and expanded resources, enhance the lipid productivity. During the Facteur 4 engineers at Fluid Imaging Technologies have recently project we aimed to develop a high-throughput strat- designed the 4thGeneration FlowCam, informally egy to obtained rich-lipid microalgae strains with a referred to as the ‘High Sensitivity FlowCam’.With mutation-selection approach. In this study, two muta- more precise fluorescence data regarding intensity, genic chemical agents were tested: ethyl methanesulfo- size, and concentration information, this new platform nate (EMS) and the acridine mutagen (ICR191) that brings about a higher level of insight into lipid produc- induce random alkylation and intercalation in microal- tion in algal cells. gae DNA. Lethal mutagenic concentrations were first assessed with the diatom Phaeodactylum tricornutum. Then, a high throughput method based on factorial 3OR.7 design was developed that allowed to test a variety of ’ combinations for the mutagenic agent concentration and UNLOCKING NATURE S TREASURE-CHEST: the exposure duration. Chl a fluorescence, optical den- SCREENING FOR OLEAGINOUS ALGAE sities (OD680nm and OD800nm) in the resulting popu- Stephen Slocombe ([email protected]), lations were monitored in 24-well plates to statistically John G Day ([email protected]) and Michele S assess survival and growth rates. Results showed that Stanley ([email protected]) exposure duration for ICR treatment did not affect survival rate contrary to EMS treatment. Survival rate was a MMB, SAMS, Oban PA37 1QA, United Kingdom decreasing and linear function of the ICR and EMS concentrations inside the experimental domain. Five P. Micro-algae synthesize high levels of lipids, carbohy- tricornutum mutant populations for each mutagen were drates and proteins photoautotrophically, thus attracting selected and showed survival rates from 1% to 90%. For considerable interest for the biotechnological production the five populations, cells were stained with the Nile red of fuels, environmental remediation, functional foods dye and cells demonstrating the 10% highest Nile red and nutraceuticals. Currently, only a few micro-algae fluorescence were then sorted and collected by flow species are grown commercially at large-scale, primarily cytometry previous to lipid analysis. The selected popu- for “health-foods” and pigments. For a range of potential lations we exposed to a second round of mutation-selec- products (fuel to pharma), high lipid productivity strains tion and screened for their fatty acids content (total, are required to mitigate the economic costs of mass neutral and polar lipids) and change in fatty acid classes. culture. Here we present a screen concentrating on marine micro-algal strains, which if suitable for scale-up would minimise competition with agriculture for water. 3OR.6 Mass-Spectrophotometric analysis (MS) of nitrogen (N) and carbon (C) was subsequently validated by measure- CHARACTERIZATION OF LIPIDS IN ALGAE ment of total fatty acids (TFA) by Gas-Chromatography UTILIZING AN IMAGING FLOW (GC). This identified a rapid and accurate screening CYTOMETER (FLOWCAM) strategy based on elemental analysis. The screen identifi Michael Joyce Cohrs (joyce.brown@fluidimaging.com) ed Nannochloropsis oceanica CCAP 849/10 and a marine isolate of Chlorella vulgaris CCAP 211/21A as Algae Technology, Fluid Imaging Technologies, Inc., the best lipid producers. The most productive diatom Scarborough 04074, United States strain was Cylindrotheca fusiformis CCAP 1017/2. Analysis of C, N, protein, carbohydrate and Fatty Acid Establishing optimal micro algae production conditions (FA) composition identified a suite of strains for further and harvesting methods is a challenge in Algae biotechnological applications e.g. Dunaliella polymor- Technology Industries. The ability to effectively charac- pha CCAP 19/14, significantly the most productive for terize the lipid content of algae and the effectiveness of carbohydrates, and Cyclotella cryptica CCAP 1070/2, bio-reactors is essential to tipping the balance in the cost with utility for EPA production and N-assimilation. effectiveness of algae production. Here we present a semi-automated method that takes advantage of the fluorescence detection and measuring capabilities of an 3OR.8 imaging flow cytometer (FlowCam) to measure the IONIC LIQUID ASSISTED SUBCRITICAL relative lipid content in algal cells. Used in conjunction WATER PROMOTES THE EXTRACTION OF with the Nile Red stain, the instrument both detects and LIPIDS FROM WET MICROALGAE measures lipid content in cells, allowing the user to SCENEDESMUS SP. rapidly gauge lipid production in algal cultures. This presentation will outline the method of performing Xiaolin Chen1 ([email protected]), Lin Song2 lipid production characterization through this imaging ([email protected]), Song Liu1 ([email protected]. Keynote and Oral Papers 42 cn), Ronge Xing2 ([email protected]), Huahua (Neori 2013). Filter feeder fish (world production ~ Yu 3 (yuhuahua @qdio.ac.cn) and Pengcheng Li1 10 mmt y−1) ingest 12-30 ton plankton to produce a ([email protected]) ton of fish. ‘Green water’ is the basis of polyculture – a leading form of aquaculture. It is sustainable and profit- 1Marine Biotechnology, Institute of Oceanology, able, thanks to the dual function of the plankton in taking Chinese Academy of Sciences, Qingdao 266000, care of the two main processes in aquaculture – produc- China; 2Marine Biotechnology, Institute of tion of food and maintaining water quality. The plankton Oceanology, Chinese Academy of Sciences, Qingdao is a low cost fish feed, whose production involves envir- 266071, China and 3Marne Biotechnology, Institute onmental services of waste disposal and water oxygena- of Oceanology, Chinese Academy of Sciences, tion. Therefore, polycultured fish, most of them Qingdao 266000, China planktivorous, supply cheap seafood for large markets. In the top ten animal species aquacultured in 2012 (FAO Presently, microalgae are considered one of the most statistics), seven were low-value greenwater carps, tila- promising feedstocks. However, a large scale and pia and clams. The cultured planktivorous bivalves efficient extraction method is costly to implement. (~15 mmt y−1) ingest 15-25 ton natural plankton to Therefore, in this paper, we examine the use of an produce a ton. The total quantity of algae used in aqua- environmentally friendly solvent-ionic liquid assisted culture, therefore, surpasses by many folds total world subcritical water method to extract lipids from wet aquaculture production reported by the FAO. The opera- Scenedesmus sp. The extraction efficiency under var- tion of polyculture fishponds is fine-tuned according to ious experimental conditions was evaluated. The opti- climate, local species, resources, markets etc. Proper fish mal experimental parameters consisted of the ionic species diversity with complementary feeding habits, liquid species [HNEt3][HSO4], a 1% concentration added to well-controlled rates of waste loading and of ionic liquid species- [HNEt3][HSO4], and a tem- water exchange, attain a balanced feeding of the differ- perature of 110°C. The lipid yield under the optimal ent plankton and plant categories. The result is an opti- conditions (35.67% dried weight biomass) was close mal use of pond resources and maximal the farm’s to that of the Bligh & Dyer method (35.32% dried output. The supply of ‘natural’ plankton to coastal weight biomass). However, the triacylglycerol content bivalve aquaculture is also influenced by coastal nutrifi- (73.63% total lipids) was higher than that of the Bligh cation, farm location and design. Increased scientific & Dyer’s method (60.44% total lipids). In addition, attention to ‘green water’ plankton may cost-effectively algae cell residues assembled into microspheres, and sustainably raise world seafood production. Neori, therefore, they were easy to separate from the mixture. A, 2013. ‘Greenwater’ aquaculture: the largest aquacul- Generally, the new extraction method is environmen- ture sector in the world. World Aquaculture 44 (2): tally friendly, efficient and easy to scale up. 26-30

3OR.9 3OR.10 ALGAE ARE THE CENTERPIECE OF WORLD MICROALGAE AS A RENEWABLE RAW AQUACULTURE, FEEDING FISH AND MATERIAL CULTIVATED IN AN URBAN CLEANING WATER AREA Amir Neori1 ([email protected]), Olga Yurievna2 Dominik Johannes Patzelt1 (dominik.patzelt@uni- ([email protected]) and Moshe Agami3 hamburg.de), Stefan Hindersin2 (s.hindersin@ssc- hamburg.de), Martin Kerner2 (m.kerner@ssc- 1National Center For Mariculture, Israel hamburg.de) and Dieter Hanelt1 (dieter.hanelt@uni- Oceanographic & Limnological Research Ltd., 88112 hamburg.de) Eilat, Israel, 2Laboratory of Ecological and Toxicological Reseach, Russian Federal Research 1Biology Department, University of Hamburg, Institute of Fisheries & Oceanography (VNIRO), Hamburg 22609, Germany and 2Strategic Science 107140 Moscow, Russia and 3Department of Consult SST Ltd., Hamburg 22761, Germany Molecular Biology and Ecology of Plants, The George S. Wise Faculty of Life Sciences, Tel Aviv The world’s first algae house in Hamburg, Germany University, 6997801 Tel Aviv, Israel was established in 2013. The innovative and sophisticated system enables an energy concept that brings ‘Green water’ plankton - microalgae, bacteria, fungi, together, in one circuit, solar energy, geothermal protozoa and small zooplankton – lead aquaculture. energy, a condensing boiler, district heating, and the Over 200 million metric tons y−1 (mmt y−1)ofmicro- production of microalgal biomass in the bioreactor algae are cultured in artificial water impoundments, façade. The 129 unique photobioreactors that cover fertilized and carefully stoked by mixed fish species an area of 200 m2 produce biomass for energy Keynote and Oral Papers 43 production and also research applications. In this containing the nutrients of the microalgal biomass. study, the biomass obtained in the photobioreactors The green algae Acutodesmus obliquus was cultivated was harvested and eventually converted under super- with this nutrient source in order to assess the biomass critical water conditions into gaseous energy-rich parameters and fatty acid productivity. Biomass and molecules (mainly H2,CH4 and C2H6). Gasification fatty acid productivity of algae grown on the effluent efficiencies of the biomass up to 98% were reached. water reached up to 1.3 g L−1d−1 and 312.9 mg L−1 With regard to the scarcity of nutrients and their global d−1, respectively, and were comparable to control depletion within the next generations, it is necessary medium. These results indicate that the residual to find solutions that allow the regeneration of these water from hydrothermal gasification can be partially nutrients that are used for agricultural biomass pro- applied as a sole nutrient source for large scale production. Therefore, the effluent water of the hydro- duction of algal biomass and be a sustainable substi- thermal conversion was divided into two fractions tute for commercial fertilizers. Keynote and Oral Papers 44

4. Algae-microbiome interactions: integrative overview from biology to chemistry

4KN.1 2UMR1087, Institut de Recherche Thérapeutique de ’ 3 ARE BIOLOGICAL CONTROLS OF HARMFUL l Université de Nantes, Nantes 44007, France; FR ALGAL BLOOMS STABLE OVER TIME? 2424, Station Biologique de Roscoff - Sorbonne Universités-CNRS, Roscoff cedex 29688, France; Laure Guillou ([email protected]) 4UMR6074, Université de Rennes 1 - CNRS, IRISA, IRISA, Rennes cedex 35042, France; 5UMR 6241, UMR 7144, Sorbonne Universités & CNRS, Station LINA, CNRS, EMN & Université de Nantes, Nantes Biologique de Roscoff, Roscoff 29682, France cedex 44322, France and 6UMR6074, Université de Rennes 1 - CNRS, IRISA, IRISA, Rennes cedex 35042, Several active microeukaryotic parasitoids are known France to be efficient biological controls of harmful algal blooms. These parasitoids, which belong to different Increasing evidence exists that bacterial commu- eukaryotic lineages, have a convergent live cycle strat- nities interact with and shape the biology of algae, egy. Infection processes generally end in 2-4 days by and that their evolutionary histories are connected. the dead of the unicellular host and the production of Considering interactions between algae and asso- hundreds of free-living zoospores release into water, ciated bacteria is therefore a key to understanding ready to initiate a novel infection. This mode of propa- the biology and evolution of these organisms. A gation well explains how such parasitoids can control striking example for this is the brown algal genus their host populations during blooms. These parasitoids Ectocarpus, which comprises a strain that has are specialist to generalist, but generally failed to infect recently colonized freshwater, a rare transition in all host strains cross-infect in culture. Complex coevo- this lineage. Our results demonstrate that this fresh- lutionary processes have been observed between the water strain depends on bacteria for this transition: host and its parasitoids even during the short period cultures that have been deprived of their associated lasts by a bloom (few weeks). Inter-annual monitoring microbiome do not survive the transfer to freshwater, survey determined that these biological controls are but restoring the associated microflora also restores rather unstable over time. The capacity of harmful the capacity to acclimate to this change. We gener- algal species to escape parasitoids and blooms results ated an inventory of bacteria associated with this alga from fragile equilibriums that could be frequently upset when cultivated in different salinities, and show that by human activities. the bacterial community composition was affected by this abiotic factor. Examining a range of other closely related algal strains, we observed that the 4KN.2 presence of two bacterial operational taxonomic MICROBIOMES IMPACT ALGAL units correlated significantly with an increase in ACCLIMATION: THE EXAMPLE OF A low salinity tolerance of the alga. Despite differences FRESHWATER STRAIN OF ECTOCARPUS in the community composition, no indications were found for functional differences in the bacterial meta- Simon M Dittami1 ([email protected]), genomes predicted to be associated with algae in the Angélique Gobet1 ([email protected]), Laëtitia different salinities tested, suggesting functional Duboscq-Bidot2 (laetitia.duboscq-bidot@univ- redundancy in the associated bacterial community. nantes.fr), Morgan Perennou3 (perennou@sb-roscoff. To study complex ‘holobiont’ system such as that of fr), Erwan Corre3 ([email protected]), Clémence the freshwater strain and its associated microbiome Frioux4 ([email protected]), Guillaume in changing environmental conditions, we propose a Collet4 ([email protected]), Jeanne Cambefort4 metabolism-centered approach that uses combined ([email protected]), Damien Eveillard5 metabolic models of both algae and bacteria. First ([email protected]), Anne Siegel6 examples of how these approaches may be imple- ([email protected]), Catherine Boyen1 (boyen@sb- mented in Ectocarpus will be given in the talk. We roscoff.fr) and Thierry Tonon1 ([email protected]) anticipate this approach will prove valuable to study 1UMR8227, Station Biologique de Roscoff - Sorbonne algal-bacterial interactions both in controlled labora- Universités-CNRS, Roscoff cedex 29688, France; tory- and, in the long run, in natural conditions. Keynote and Oral Papers 45

4OR.1 Sexual reproduction of an araphid pennate diatom Pseudostaurosira trainorii has been observed in detail THE MICROBIOME OF A SEAWEED INVADER and the involvement of sex-pheromone at its onset ACROSS ITS INTRODUCED EUROPEAN was experimentally documented as follows: (1) vege- RANGE tative cells of female clone release their sex phero- Aschwin H Engelen ([email protected]), Anita Klaeui mone ph-1 when they are in the sexual size window; ([email protected]), Tania Aires (taniaires@ (2) when a male cell detects the pheromone ph-1, the gmail.com) and Ester A Serrão ([email protected]) cell is sexualized to produce and release the gametes; (3) at the same time, the male pheromone ph-2 is also MAREE, CCMAR, Faro 8005 139, Portugal secreted to let the female sexualized and releases the gamete (egg). Although this reciprocal pheromone Anthropogenic activities result in environmental and interaction must take place at the onset of sexual ecological changes from local to global scales, with reproduction at natural conditions, I recently found biological invasions, climate change and habitat destruc- the fact that it is also possible to artiﬁcially stimulate tion among the most problematic ones. Through various sexualization of male cells solely by antibiotics treat- pathways, these activities alter marine ecosystems from ment with the absence of female clone or its sex the smallest to the largest scale. Research on how organ- pheromone. Bacterial involvement in this phenom- isms cope with stress and environmental change has enon is suggested since the gamete formation is not traditionally focused on individuals and populations. reproducible with axenic culture. Presence or absence Genetic diversity is important for the success of popula- of the induction of gamete formation with antibiotics tions in adapting to changing environmental factors. is mainly depending on the classes of antibiotics Introduced species are faced with tremendous challenges added to the culture medium. Most of aminoglyco- when introduced beyond their native range. Not only do sides, which inhibit protein synthesis, are “positive” they have to cope with new environmental conditions, (i.e. treatment stimulates the release of gametes), competitors and predators, mostly their populations are whereas the other classes are generally negative, small and with very limited genetic diversity. The holo- with a few exceptions such as zeocin (glycopeptides) biont and hologenome theories pose that the diversity of and tetracycline (tetracyclines) that display positive associated microbes and viruses provide a range of results, albeit weakly. Among aminoglycosides, strep- services to their host that are important for performance tomycin is the most effective, followed by gentamicin, and adaptation. In this study, we explore bacterial com- hygromycin B and neomycin. The other aminoglyco- munities associated to one of the most successful inva- sides, such as kanamycin, geneticin (G418), nourseo- sive seaweeds of our time using next generation thricin, are also shown to be moderately positive. A amplicon sequencing of the 16S rRNA gene. We comparative metabarcoding analysis of bacterial ﬂora hypothesize that associated bacterial communities with/without antibiotic treatment is currently ongoing might play a role on the success of their host, as bacteria and the result will be presented. can affect the morphogenesis, development, growth, metabolism and the immune system of their algal host. Our descriptive approach exploring the diversity and composition of Sargassum muticum associated bacterial 4OR.3 communities across European latitudinal gradient cover- PHYLOGENETIC DIVERSITY OF EPIBIOTIC ing both northern (Norway) and southern (Morocco) GRAM-POSITIVE BACTERIA ISOLATED invasion fronts aims to show to what extent micro- FROM ANTARCTIC MACROALGAE biomes change geographically or with invasion phase Pamela Alvarado1 ([email protected]), Ying and among different tissue types of the host. We apply a Huang2 ([email protected]), Jian Wang2 metagenomic approach to provide functional informa- ([email protected]), Ignacio Garrido3 (garridoigna- tion, and experimental manipulations of CO and gra- 2 [email protected]), María J Diaz3 (mjdiaza@gmail. zers to reveal adaptative aspects of the associated com), Jorge Holtheuer3 ([email protected]) microbiomes. and Sergio Leiva1 ([email protected]) 4OR.2 1Instituto de Bioquímica y Microbiología. Campus AN IMPLICATION OF BACTERIA-DIATOM Isla Teja., Universidad Austral de Chile, Valdivia INTERACTION AT THE ONSET OF SEXUAL Casilla 567, Chile; 2State Key Laboratory of REPODUCTION IN DIATOMS Microbial Resources, Institute of Microbiology, Shinya Sato ([email protected]) Chinese Academy of Sciences, Beijing 100101, China; 3Instituto de Ciencias Marinas y Marine Bioscience, Fukui Prefectural University, Limnológicas. Campus Isla Teja., Universidad Fukui 917-0003, Japan Austral de Chile, Valdivia Casilla 567, Chile Keynote and Oral Papers 46

The Antarctic continent is of exceptional biological and Atmosphere Flagship, CSIRO, Hobart 7000, interest, possessing a rich diversity of marine macroal- Australia; 4Institute of Marine and Antarctic Studies, gae and a high endemism. However, very little is known University of Tasmania, Launceston 7250, Australia about the diversity and bioactive potential of bacteria and 5Environmental Chemistry, Australian Institute of associated with the surface of Antarctic macroalgae. Marine Science, Townsville 4810, Australia Antarctic macroalgae are an untapped source of microbial diversity and represent a promising source of novel The Australian National Algae Culture Collection, therapeutic agents. This study aims to explore the phy- ANACC, maintains over 1000 strains of microalgae logenetic diversity and antimicrobial activity of Gram- from Australian marine, estuarine and fresh waters positive bacteria isolated from the surface of intertidal from the tropics to Antarctica. As one of the six and subtidal Antarctic macroalgae. Gram-positive bac- National Research Collections Australia, it is a signifi- teria are well-known producers of secondary metabo- cant respository of characterised Australian algal biodi- lites. Representative species of green (Monostroma versity. ANACC has developed along with CSIRO’s hariotii), red (Iridaea cordata, Phycodrys antarctica, research programs addressing national priorities, with Pyropia endiviifolia) and brown algae (Adenocystis utri- strains having relevance to environmental issues and cularis) were collected from the intertidal and subtidal the development of microalgae as a bioresource. zone (5 and 30 m) of King George Island, Antarctica, in Interfacing ecosystem knowledge with bioresource January 2014. Surface-associated bacteria were investi- potential is a focus for ANACC. Studying the interac- gated by cultivation-based methods and 16S rRNA gene tions of environmentally significant bloom forming sequencing. Epibiotic bacteria were screened for anti- microalgae with bacteria has demonstrated the impor- bacterial activity against a panel of 6 antarctic macro- tance of considering algal growth dynamics within the algae-associated microorganisms. In total, 50 Gram- microbiome. We have demonstrated highly synergistic positive strains were isolated, which were affiliated to growth dynamics of a Marinobacter strain with the toxic 12 families of bacteria, predominantly Actinobacteria dinoflagellate Gymnodinium catenatum whereas no such as Micrococcaceae, Microbacteriaceae, Nocardia- such synergy was seen with another bacterial strain, ceae, Dermabacteraceae, Pseudonocardiaceae and also isolated from cultured G. catenatum.Itwasalso Streptomycetaceae. Antimicrobial activity was found found that the bacterial community can alter intracellular in isolates of Agrococcus, Brachybacterium, paralytic shellfish toxin production of dinoflagellates, Citricoccus, Kocuria and Streptomyces.Thisstudy most likely to be due to bacterial effects on dinoflagellate shows a high diversity of Gram-positive bacteria on physiology rather than bacterial biotransformation of Antarctic macroalgae as well as highlights their potential toxins. Another ecologically significant microalga is to produce antimicrobial compounds. Acknowledge- the green alga Botryococcus braunii that forms colonies ments: This study was supported by Grant RT_06-13 held together by a lipid biofilm matrix. This species from the Instituto Antártico Chileno (INACH). We produces high amounts of hydrocarbons and is of great thank the INACH staff at Station Prof. Julio Escudero interest as a source of biofuels. However, its slow growth for logistic support. Special thanks to Dr Iván Gómez hampers such bioresource development. We have iso- and his group (Proyect Anillo ART1101) for its valuable lated and characterized Botryococcus strains from popu- support during the field work. lations spanning tropical to temperate Australia. Chemical Races A, B and L have been identified including one population consisting of two Races. 4OR.4 Investigations into growth of Botryococcus include the bacterial communities associated with the cultured AUSTRALIAN NATIONAL ALGAE CULTURE strains. Our results demonstrate the importance of con- COLLECTION – UNIQUE BIODIVERSITY sidering the interactions of microalgae within the micro- INFORMING ECOSYSTEM KNOWLEDGE biome as a key part of ecosystem knowledge and AND BIORESOURCES bioresource development. Susan I Blackburn1 ([email protected]), Ian D Jameson1 ([email protected]), Maria E Albinsson2 ([email protected]), Sharon 4OR.5 Appleyard3 ([email protected]), Graeme 3 DIFFERENTIATION IN BACTERIAL Dunstan ([email protected]), Christopher 4 COMMUNITIES ASSOCIATED TO THE RED J.S. Bolch ([email protected]), Andrew P 5 2 SEAWEED GENUS ASPARAGOPSIS IN THE Negri ([email protected]) and Andrew Revill WESTERN ATLANTIC AND THEIR ([email protected]) POTENTIAL DRIVERS 1National Research Collections Australia, CSIRO, Tania Aires ([email protected]), Aschwin H Hobart 7000, Australia; 2Ocean and Atmosphere Engelen ([email protected]) and Ester A Serrão Flagship, CSIRO, Hobart 7000, Australia; 3Oceans ([email protected]) Keynote and Oral Papers 47

Marine Ecology and Evolution, CCMAR, University The dominant primary producers in headwater rivers of Algarve, Faro 8005-139, Portugal are microphytobenthic communities. As well as playing an important role in primary productivity, these Biological invasions can induce harmful alterations, communities of algae, bacteria, fungi, and other from genes to ecosystems, and are considered one of microorganisms also play a larger role in nutrient the most harmful components of global change. The transformation at the sediment-water interface. These genetic pool of introduced species greatly influences communities are however subject to interactions their capacity to establish and expand. The hologen- which may influence this important ecosystem ser- ome theory states that associated microorganisms sup- vice. One such interaction – trophic coupling – pro- ply their host with extra capabilities that might lead to vides a positive feedback loop allowing high biomass faster adaptation and positive response to the new to occur in low nutrient/DOC conditions. However, invaded environment. A relative low but increasing this is disrupted in contrasting environments where number of studies have provided evidence that bac- DOC is not limiting. We aim to examine these micro- teria associated to macro-organisms determine for a phytobenthic communities by characterising them large part the well-being of their host, making them a across a gradient of river sub-catchment geology potentially essential element of evolution and adapt- types. Here we present results from a study of soft ability of the holobiont. Among the 100 worst inva- sediment microphytobenthic communities in the sive alien species and introduced in many places Hampshire Avon river catchment, United Kingdom. around the globe are representatives of the red sea- Multiple rivers from different clay, greensand and weed genus Asparagopsis, which includes two differ- chalk geology sub-catchments were sampled in a spa- ent species, A. armata and A. taxiformis. Both have a tial-temporal design throughout 2013. Results showed haplo-diplontic, heteromorphic life cycle with alter- that these rivers represent a natural light/DOC gradi- nating haploid gametophytes and diploid sporophytes. ent, which influenced the overall trophic dynamics of A. armata (a genetically homogeneous taxon) is a the microphytobenthic communities. Algal biomass temperate species native to southern Australia and was higher in chalk sub-catchments, while diatom New Zealand, whereas A. taxiformis is a cryptic spe- community composition showed distinct differences cies complex composed of at least five genetically in species richness, diversity and species present distinct lineages, each characterized by a distinct geo- between net-autotrophic and net-heterotrophic sys- graphical distribution. Here, we compare bacterial tems.. These patterns were replicated in algal EOC communities of both Asparagopsis species including production; multiple carbohydrate fractions are posi- the haplodiplont stages of A. armata and two lineages tively correlated to DOC concentrations, however of A. taxiformis in the West Atlantic from mainland they showed no relationship to other macronutrients Portugal to oceanic islands. In addition, we investigate such as nitrate & phosphate. Net autotrophic commu- the invasive potential, based on associated bacteria nities showed significant flux of nitrite from the sedi- putative function, of the two invasive taxonomic enti- ment to the water column, and a similar flux of ties in South Portugal. Preliminary results show that phosphate – both of which were not seen in the hetero- the cryptic separation of A. taxiformis lineages is also trophic communities. Positive correlations were supported by their bacterial community composition observed between river DOC and sediment EOC, and, invasive taxa in South Portugal, display a wider which suggests that trophic coupling state depends selection of bacterial OTUs that might be involved in on DOC concentration. High DOC/EOC ratios and the adaptation of the invasive taxa. light controlled incubation experiments infer that in high DOC rivers, bacteria are able to outcompete algae for macronutrients, leading to microphyto- 4OR.6 benthic communities shifting from net-autotrophy to heterotrophy. LIGHT AND DISSOLVED ORGANIC CARBON DRIVE INTERACTIONS WITHIN RIVER MICROPHYTOBENTHIC COMMUNITIES Scott L Warren1 ([email protected]), Boyd A 4OR.7 2 2 McKew ([email protected]), Corinne Whitby EFFECTS OF FUNGAL PARASITISM ON 2 ([email protected]) and Graham JC Underwood FRESHWATER CYANOBACTERIAL BLOOMS ([email protected]) Télesphore Sime-Ngando1 (telesphore.sime- 1 1School of Biological Sciences, University of Essex, [email protected]), Mélanie Gerphagnon Colchester CO3 4SQ, United Kingdom and 2School of ([email protected]), Jonathan Colombet1 ([email protected]), Biological Sciences, University of Essex, Colchester 2 CO4 3SQ, United Kingdom Claire MM Gachon ([email protected]) and Keynote and Oral Papers 48

Delphine Latour1 (delphine.latour@univ- are compared to most host-virus systems. Given what bpclermont.fr) we now know about phaeoviruses, unlocking the hid- den diversity within other seaweed systems has the 1UMR CNRS 6023, Laboratoire Microrganismes: potential to fundamentally change concepts within Génome et Environnement, Université Blaise Pascal, Virology and Phycology alike. Clermont-Ferrand I, Aubière 63178 Cedex, France and 2Culture Collection of Algae and Protozoa, SAMS, Scottish Marine Institute, Dunbeg, Argyll, 4OR.9 PA37 1QA, United Kingdom LIFE CYCLE STRATEGIES OF A LARGE Many species of phytoplankton are susceptible to para- VIRUS THAT INFECTS THE BLOOM sitism by fungi from the phylum Chytridiomycota (i.e. FORMING EMILIANIA HUXLEYI chytrids). However, few studies have reported the Daniella Schatz1 ([email protected]), effects of fungal parasites on filamentous cyanobacterial Adva Shemi1 ([email protected]), Shilo blooms. To investigate the missing components of Rosenwasser1 ([email protected]), bloom ecosystems, we examined an entire field bloom Sharon G Wolf2 ([email protected]), of the cyanobacterium Anabaena macrospora for evi- Sergey Malitsky3 ([email protected]) dence of chytrid infection in a productive freshwater and Assaf Vardi3 ([email protected]) lake, using a high resolution sampling strategy. A. macrospora was infected by two species of the genus 1Plant and Environmental Sciences, Weizmann Rhizosiphon which have similar life cycles but differed Institute of Science, Rehovot 7610001, Israel; in their infective regimes depending on the cellular 2Chemical Research Support, Weizmann Institute of niches offered by their host. R. crassum infected both Science, Rehovot 76100, Israel and 3Plant and vegetative cells and akinetes while R. akinetum infected Environmental Sciences, Weizmann Institute of only akinetes. A tentative reconstruction of the devel- Science, Rehovot 76100, Israel opmental stages suggested that the life cycle of R. crassum was completed in about 3 days. The infection The coccolithophore Emiliania huxleyi forms massive affected 6% of total cells (and 4% of akinetes), spread blooms in the oceans that are terminated by a large over a maximum of 17% of the filaments of cyanobac- double-stranded DNA coccolithovirus, the Emiliania teria, in which 60% of the cells could be parasitized. huxleyi virus (EhV). The cellular mechanisms that Furthermore, chytrids may reduce the length of fila- govern the replication cycle of this virus are largely ments of Anabaena macrospora significantly by unknown. Here we show that hallmarks of autophagy, ‘‘mechanistic fragmentation’’ following infection. All a lysosomal degradative pathway that degrades unde- these results suggest that chytrid parasitism is one of sirable or damaged macromolecules, are highly the driving factors involved in the decline of cyanobac- induced during the lytic phase of E. huxleyi viral teria blooms, by direct mortality of parasitized cells and infection. In addition to upregulation of a suite of indirectly by the mechanistic fragmentation, which autophagy related genes, we observed a host encoded could weaken the resistance of A. macrospora to autophagy related protein in EhV virions, demonstrat- grazing. ing the pivotal role of the autophagy-like process in viral assembly and egress from the cells. We further investigated the modes of viral entry and egress from 4OR.8 the cells and explored the possibility of multiple phenotypes associated with the life cycle of EhV. We PHAEOVIRUSES EXTEND THEIR HOST measured membrane lipid composition, virion ultra- RANGE TO THE KELPS structure, and infectivity and decay rates, all pointing Declan C Schroeder ([email protected]) to the different strategies of viral infection. We propose that the pleomorphic nature of EhV will have Cell & Molecular, Marine Biological Association, major implications to their ecological role during host- Plymouth PL1 2PB, United Kingdom virus dynamics within oceanic algal blooms.

Phaeoviruses infect the brown algae, Phaeophyceae. They exploit a Persistent evolutionary strategy via 4OR.10 genome integration and are the only known represen- DISEASE RESISTANCE IN BROWN ALGAE: tatives to do so amongst the giant viruses, MECHANISMS AND HERITABILITY Megaviridae. Here I will present data showing an increase in phaeovirus prevalence among brown Martina Strittmatter1 ([email protected]. algae, which has led to alternative strategies of infec- uk), Claire MM Gachon1 ([email protected]), tion. I will also show how exceptional phaeoviruses Dieter G Müller2 (dieter.gerhard.mueller@uni- Keynote and Oral Papers 49 konstanz.de), Amerssa Tsirigoti 3 (amerssa@hotmail. isms of disease resistance in brown algae are com), Stephan Wawra4 ([email protected]), Max poorly known, in contrast to the well-studied Beckmann4 ([email protected]), Christos hypersensitive response in terrestrial plants. We Katsaros3 ([email protected]), Pieter van West4 previously established a suitable experimental ([email protected]) and Fritjof C Küpper5 pathosystem and identiﬁed clonal brown algal ([email protected]) strains that exhibit differential disease susceptibility to the obligate oomycete pathogen Eu. dickso- 1Microbiology and Molecular Biology, The Scottish nii. Here we show that resistance to infection is Association for Marine Science, Oban PA37 1QA, evoked by the hypersensitive death of single algal United Kingdom; 2Fachbereich Biologie, Universität cells attacked by Eu. dicksonii. These cells express Konstanz, Konstanz 78457, Germany; 3Department the programmed cell death marker metacaspase. of Botany, University of Athens, Athens 15784, Further conserved markers of the hypersensitive Greece; 4Aberdeen Oomycete Laboratory, University response include the deposition of blue-ﬂuorescent of Aberdeen, Aberdeen AB25 2ZD, United Kingdom metabolites and beta- 1, 3-glucan, the production and 5Oceanlab, University of Aberdeen, Newburgh of reactive oxygen species, and the fragmentation AB41 6AA,, United Kingdom of DNA characteristic for programmed cell death. This hypersensitive response was observed in ten Brown algae (Phaeophyta), in addition to having algal species belonging to four different orders, an important ecological role as predominant pri- demonstrating its broad conservation among mary producers in temperate and cold coastal seas, brown algae (Phaeophyta). In addition to the are of increasing relevance to the rapidly-expand- description of disease resistance mechanisms we ing aquaculture industry. Like any other organism, have furthermore investigated the heritability of brown algae are plagued by a variety of phylogen- this trait on our model pathosystem using several etically different pathogens. However, the mechan- genealogies of Ectocarpus fasciculatus. Keynote and Oral Papers 50

5. Phylogenomics: new approaches to solving old problems in algal evolution

5KN.1 1Evolutionary Parasitology, Biology Centre CAS, Institute of Parasitology, Ceske Budejovice 37005, UNTANGLING THE WEB OF EUKARYOTIC 2 PHOTOSYNTHETIC EVOLUTION Czech Republic; Molecular Parasitology, Biology Centre CAS, Institute of Parasitology, Ceske John W Stiller ([email protected]) Budejovice 37005, Czech Republic and 3Biological and Environmental Sciences and Engineering, Department of Biology, East Carolina University, KAUST, Thuwal 23955-6900, Saudi Arabia Greenville 27858, United States Apicomplexan parasites are known to possess highly Efforts to arrive at a clear understanding of the history reduced mitochondrial genomes encoding only three of eukaryotic photosynthesis have been hindered by protein genes (cox1, cox3, cob) and fragmented rRNA two overarching problems. First, phylogenomic ana- genes. We investigated the mitochondrion of alveolate lyses have not resolved how a number of organisms algae Chromera velia and Vitrella brassicaformis,the containing plastids are related to one another, or to other closest known phototrophic relatives to Apicomplexa. organisms that are not photosynthetic. Such investiga- Genome, transcriptome and enriched mtDNA fractions tions are complicated by the global impacts of various were sequenced using Illumina platform. It appears that uncharacterized sources of bias, which can directionally while Vitrella displays the same three mitochondrial mislead tree-building algorithms and result in phyloge- protein genes as apicomplexan mitochondrion, netic artifacts. Perhaps more challenging, however, is Chromera mitochondrion holds a genome with the the second major problem, the massive horizontal smallest known coding capacity containing just two movement of genes among divergent eukaryotic protein genes (cox1, cox3) and fragmented rRNA lineages through the process of endosymbiotic gene genes. Consequently, the respiratory chain is reduced transfer (EGT), which involves correlated inheritance by the absence of complexes I (NADH:ubiquinone that is incongruent with the evolutionary history of the oxidoreductase) and III (ubiquinol: cytochrome c oxi- ’ host organisms nuclear genomes. Rigorous detection doreductase). The respiratory chain is broken into two fi of EGT can be dif cult using phylogenetic methods, parts functioning independently. Electrons from the particularly since widely accepted views of organismal first part (complex II, alternative NADH dehydro- relationships have been estimated without a clear under- genases, dihydroorotase, electron-transfer flavoprotein standing of the amount and impact of EGT on the etc.) are channeled to ubiquinone, which passes them genomes under investigation. Consequently, hypoth- to alternative oxidase, an electron sink, without any fl eses of plastid evolution inferred from con icts consequent proton pumping and link to the respiration among gene trees can be tautological and, therefore, whatsoever. Electrons for complex IV are provided by fi cannot be falsi ed using standard methodologies. This unique combination of L and D lactate cytochrome c presentation will explore alternative approaches in com- oxidoreductases. In contrast, Vitrella still has the comparative genomics that could more clearly articulate the plex III but alternative enzymes are already available in tangled path of plastids through the eukaryotic tree-of- the genome. It appears that most of non-canonical life. It also will address both philosophical and metho- enzymes involved in the respiratory chain, which dological considerations that can promote new break- were found in chromerid algae, are of early eukaryotic throughs and a better appreciation of the complex origins. evolution of eukaryotic photosynthesis.

5KN.2 5KN.3 INTERRUPTED RESPIRATORY CHAIN IN THE EVOLUTION OF PLASTID-TARGETED MITOCHONDRION OF CHROMERA VELIA PROTEINS IN THE SECONDARY PLASTID- 1 CONTAINING MIXOTROPHIC EUGLENID - Miroslav Oborník ([email protected]), Pavel RAPAZA VIRIDIS Flegontov2 (pﬂ[email protected]), Jan Michalek1 ([email protected]), Julius Lukes2 (jula@paru. Anna Karnkowska1 ([email protected]), Naoji cas.cz) and Arnab Pain3 ([email protected]) Yubuki1 ([email protected]), Vladimir Hampl1 Keynote and Oral Papers 51

([email protected]) and Brian S Leander2 1Department of Biology and Ecology, Faculty of ([email protected]) Science, University of Ostrava, Ostrava 710 00, Czech Republic and 2Institute of Molecular Genetics, Czech 1Department of Parasitology, Charles University in Academy of Sciences, Praha 4 142 20, Czech Republic Prague, Prague 12843, Czech Republic and 2Departments of Botany and Zoology, University of Eustigmatophyceae (Ochrophyta, Stramenopiles) are a British Columbia, Vancouver BC, V6T 1Z4, Canada small algal group with species of the genus Nannochloropsis, being their best studied representa- Plastids of autotrophic euglenids originated through a tives due to their potential in biotechnological applica- secondary endosymbiosis. A heterotrophic euglenid tions. Nuclear and organellar genomes have been engulfed a prasinophyte-like green alga, most likely recently sequenced for several Nannochloropsis spp., Pyramimonas, and maintained it as a permanent endo- but phylogenetically wider genomic studies are missing symbiont. This finding is supported by numerous mole- for eustigmatophytes. Here were present a comparative cular phylogenies. However, molecular data from green analysis of mitochondrial genomes of eustigmatophytes algae and euglenids are limited and phylogenetic rela- based on previously published genome sequences from tionships are mainly inferred from plastid-encoded Nannochloropsis spp. and newly sequenced genomes genes, thus exact green algal donor and early evolution from Monodopsis sp. (a close relative of of euglenid plastids are still uncertain. Rapaza viridis,a Nannochloropsis), Vischeria sp.(amoredistantly recently described mixotrophic euglenid, might shed related member of the order Eustigmatales), and new light on euglenid endosymbiosis. R. viridis pos- Trachydiscus minutus (representing the recently sesses functional chloroplasts and consumes a specific described deeply diverged clade Goniochloridales). strain of prasinophyte alga, Tetraselmis sp. Phylogenetic Our analysis has yielded a number of interesting find- analyses and ultrastructural data demonstrated the inter- ings, five of which are especially noticable. First, mito- mediate features between phototrophic euglenids and chondrial genomes of most eustigmatophytes are highly phagotrophic lineages. The basal position within auto- colinear, except that of Vischeria sp. that has been trophic euglenids suggested that R. viridis is the best highly rearranged. Interestingly, this correlates with a candidate to illuminate original traits of euglenid plas- markedly elevated substitution rate of mitochondrial tids. We analysed transcriptome obtained from R. viridis. genes in the Vischeria lineage. Second, eustigmatophyte From 107,092 assembled sequences, 8,875 are complete mitochondrial genomes uniquely share a truncated at the 5‘ terminus, based on the presence of specific nad11 gene encoding only the C-terminal part of the euglenid splice-leader. Out of these, 72 transcripts Nad11 protein, while the N-terminal part is encoded by encoding putative plastid-targeted proteins were identi- a separate gene in the nuclear genome. Third, a pre- fied based on homology to plastid proteomes and on viously unnoticed tatA gene and three mitochondrial their involvement in processes known to be localized in ORFs lacking discernible homologs elsewhere are con- the plastid. Majority of them, as we expected, shows served across the phylogenetic breadth of the class (tatA homology to green-algal-plastid proteins and is probably and two of the three unidentified ORFs are secondarily derived from the plastid donor. We also predicted plas- missing from Vischeria sp.). Fourth, Nannochloropsis tid-targeting leader sequences of over 200 transcripts spp. and T. minutus do not employ UGA as a termina- using TargetP, however majority of the identified plas- tion codon and lack the corresponding nuclear genome- tid-targeted proteins did not have a predicted plastid- encoded release factor mRF2, indicating at least two targeting leader sequence. For better predictions of tar- independent simplifications of mitochondrial translation geting to secondary plastids of R. viridis, a more specific termination in eustigmatophytes. Finally, the rps3 gene method has to be developed. Further phylogenetic ana- in the mitochondrial genome of Vischeria sp. is inter- lyses containing data from other euglenids and green rupted by the UAG codon, but the genome includes a algae will decipher evolutionary history of plastid-tar- gene for an unusual tRNA that we speculate may serve geted proteins and euglenid plastid as such. as a suppressor tRNA to properly decode the rps3 gene.

5OR.1 5OR.2 A COMPARATIVE ANALYSIS OF MITOCHONDRIAL GENOMES IN WHOLE GENOME PHYLOGENOMIC EUSTIGMATOPHYTE ALGAE ANALYSIS PROVIDES DEEPER INSIGHT 1 INTO THE ORIGINS AND DIVERGENCE OF Tereza Ševčíková ([email protected]), 1 THE CYANOBACTERIA Veronika Zbránková (veronikazbrankova@seznam. cz), Vladimír Klimeš1 ([email protected]), Hynek Noor Azlin Mokhtar1 ([email protected]. Strnad2 ([email protected]), Miluše Hroudová2 sa), Fredrick Kinyua Kamanu2 (frederick.kinyua ([email protected]), Čestmír Vlček2 (vlcek@img. @kaust.edu.sa) and John AC Archer3 (john. cas.cz)andMarekEliáš1 ([email protected]) [email protected]) Keynote and Oral Papers 52

1Computational Bioscience Research Center, King 1Marine Biological Association, Plymouth PL1 2PB, Abdullah University of Science and Technology, United Kingdom; 2Biosciences, University of Exeter, Thuwal, Jeddah 23955-6900, Saudi Arabia; 2Human Exeter EX4 4QD, United Kingdom and 3Department Nutrition Research Center on Aging, Tufts University, of Life Science and Biotechnology, Shimane Boston MA 02111, United States and 3Computational University, Shimane 690-8504, Japan Bioscience Research Center, King Abdullah University of Science and Technology (KAUST), Ascorbic acid (vitamin C) plays an important role in Thuwal, Jeddah 23955-6900, Saudi Arabia protecting photosynthetic eukaryotes against reactive oxygen species derived from the chloroplast. However, Phylogenetic trees of cyanobacteria based on 16S rRNA the role of ascorbate in plastid acquisition is unclear, as and multilocus sequence analysis (MLSA) consistently the evolutionary origins of ascorbate biosynthesis reveal that although the cyanobacterial clade is mono- remain unknown. Most eukaryotes require ascorbate, phyletic, sub-sections I, II and III are polyphyletic whilst but multiple animal lineages have become ascorbate terminally differentiated sub-section IV/Vare monophy- auxotrophs due to the loss of the terminal enzyme in the letic. However, these approaches do not engage with the biosynthetic pathway, L-gulonolactone oxidase majority of the genome that encodes more rapidly evol- (GULO). GULO produces hydrogen peroxide, which ving or horizontally acquired genes and regulatory path- may have provided selective pressure for its repeated ways (DNA-based and RNA-based) that may play a loss. GULO is absent from land plants and Euglena, critical role in the biology of the cell and that are often which use an alternative terminal enzyme, L-galacto- specific to that organism/ecological niche. This is parti- nolactone dehydrogenase (GLDH) in their respective cularly important for cyanobacteria that as a group pathways. The evolutionary processes resulting in the encode a surprisingly high number of proteins that presence of these multiple pathways are not well under- have no detectable similarity to protein sequences out- stood. We present evidence that GULO has been lost with the group. Because these are not universal, this and replaced by GLDH in almost all photosynthetic important class is not included in cyanobacterial eukaryotes. We find that GULO and GLDH have a MLSA. To address these issues and attempt to derive a mutually exclusive distribution and surprisingly iden- cyanobacterial phylogeny that takes into account the tify GULO in basally derived members of the entire cellular genome, we have applied a phylogenomic Archaeplastida (Plantae). Red algae use a modified algorithm PHYLOGENOME running on a high perfor- form of the pathway found in plants and green algae, mance compute system to perform reciprocal whole in which D-mannose and L-galactose are precursors. genome DNA sequence comparisons to compute geno- However, algae that have acquired plastids via second- mic distances that are used to reconstruct phylogeny and ary endosymbiosis demonstrate a hybrid pathway ana- perform tree reliability assessment using bootstrapping. logous to that found in animals, but using GLDH rather In this study, we assembled the largest available assem- than GULO as the terminal enzyme. We propose that bly of 177 cyanobacterial completed and draft genomes the development of the photoprotective role of ascor- distributed across 51 genera with representatives from bate in ancestral Archaeplastida, to counter the produc- each of morphological sub-sections I-V and generated tion of reactive oxygen from the chloroplast, may have the first comprehensive phylogenomic reconstruction of provided selective pressure to functionally replace this phylum. This phylogenomic model is robust with GULO with GLDH, in order to uncouple ascorbate respect to genome assembly status, base sequence errors synthesis from H2O2 production and provide a high and annotation errors. Our data indicate that marine capacity ascorbate biosynthesis pathway. The func- picocyanobacteria diverged very early from the rest of tional replacement of GULO with GLDH may there- the cyanobacterial groups in this study. Furthermore, our fore have played an important role in protecting the analysis shows structurally diverse sub-section II, III, IV host cell against photo-oxidative stress following plas- and V cyanobacteria are likely to have arisen from tid acquisition. unicellular ancestral cells. Sub-section IV/V (heterocys- tous) cyanobacteria are monophyletic and descendent 5OR.4 from filamentous Trichodesmium ancestors. GRACILARIOPSIS ANDERSONII GENOME ENCODES SEVERAL CLUES TO 5OR.3 MAINTAINING A PERMISSIVE PARASITE EVOLUTION OF ALTERNATIVE PATHWAYS ENVIRONMENT FOR VITAMIN C SYNTHESIS FOLLOWING Nicolas Blouin ([email protected]) and Christopher PLASTID ACQUISITION Lane ([email protected]) Glen L Wheeler1 ([email protected]), Nicholas Smirnoff2 ([email protected]) and Takahiro Department of Biological Sciences, University of Ishikawa3 ([email protected]) Rhode Island, Kingston 02881, United States Keynote and Oral Papers 53

By far, the largest numbers of formerly photosynthetic of Le Mans, Le Mans 72085, France and 3GreenSea, parasites are found among the red algae. There are Mèze 34140, France examples of extant parasitic taxa from nearly half the recognized floridiophyte orders and there appear Studying transcription factors (TFs), one of the key to be nearly a hundred independent parasite lineages players in gene expression is of outstanding interest to within these groups. Because there are so many investigate the evolutionary history of organisms independent evolutionary events of parasitism through lineage-specificfeatures(Langet al., 2010; within the red algae and it appears that parasites Rayko et al., 2010; Sharma et al., 2013). In this kind have most often evolved from a shared ancestor of study, some gaps exist in term of available genome with their hosts, this is an intriguing group to explore from certain lineages such as rhodophytes and hapto- the evolutionary changes concomitant with a transi- phytes. In this study, we realized the genome-wide iden- tion from a free-living to parasitic lifestyle. For much tification and comparison of TFs in algal lineages adding of their life history many red algal parasites live out a new haptophyte genome (Tisochrysis lutea)andthe their lives as a nucleus and a collection of mitochon- rhodophyte P. purpureum. To reach this goal, a new dria freely intermingling with the host’s organelles optimized and automated pipeline for the TFs identifica- (including the modified plastid, i.e., proplastid) tion was developed. This pipeline combines research of within host cells. In order to live in this manner, similarities from known TFs (BLAST) and functional they must be capable of altering host cell walls, protein domains annotation using a large database con- establishing intracellular zones of influence, direct- taining plant, fungi, mammalian and cyanobacteria TFs ing cytochemistry globally within the heterokaryon (InterProScan5 and HMMER3 freewares). Using this cells and directing nutrients into tissues where para- tool, the TF complements of seven algae were estab- site nuclei exist. As the first step in understanding lished and compared to each other. This comparative how the parasite relationship has repeatedly evolved study includes algae from two closely related lineages in the red algae and why parasites are so well toler- (Andersen, 2004; Moustafa et al., 2009), the hapto- ated as intracellular guests, we have sequenced the phytes (Tisochrysis lutea, Emiliania huxleyi and genome of Gracilariopsis andersonii and Pavlova sp.) and the stramenopiles (the Gracilariophila oryzoides, its obligate parasite with Eustigmatophycea, Nannochloropsis gaditana and the a combination of Illumina and PacBio sequencing. diatom Phaeodactylum tricornutum), as well as the We have now finished assembly of the 108.4 Mbp green alga Chlamydomonas reinhardtii and the meso- Gr. andersonii genome. Among 9,363 predicted pro- philic red alga Porphyridium purpureum. The specificity tein set for Gr. andersonii,wehaveidentified the of our pipeline allowed us to identify the presence of plastid-targeted and membrane-bound secretome cyanobacterial TFs in the nuclear genome of algae for gene sets. These genes provide promising targets the first time. Moreover, our study confirms and high- for examining how gene synteny and protein simi- lights some lineage-specific features in haptophytes and larity may facilitate initial infection and sustained stramenopiles. This work provides a basis to better compatibility between the host and parasite. understand gene regulation in T. lutea, a species of ecological interest because haptophytes are genetically diverse and often dominant in the planktonic photic realm. 5OR.5 GENOME-WIDE PREDICTION AND COMPARATIVE ANALYSIS OF 5OR.6 TRANSCRIPTION FACTORS IN WHO WAS THE LAST APLASTIDIC MICROALGAE CRYPTOPHYTE? 1 Stanislas Thiriet-Rupert (Stanislas.Thiriet. Kasia Piwosz ([email protected]) [email protected]), Grégory Carrier1 (Gregory. 2 [email protected]), Benoît Chenais (Benoit. Department of Fisheries Oceanography and Marine [email protected]), Camille Trottier1 (Camille. 1 Ecology, National Marine Fisheries Research [email protected]), Gaël Bougaran (Gael. Institute, Gdynia 81-332, Poland [email protected]), Jean-Paul Cadoret3 (jeanpaul 2 [email protected]), Benoît Schoefs (benoit. Cryptophytes are a cosmopolitan group of algae. They 1 [email protected]) and Bruno Saint-Jean are abundant in spring and summer, and are important ([email protected]) food source for micro- and mesozooplankton. Around 200 of species have been described, but phylogeny 1Physiology and Biotechnology of Algae Laboratory, 2 and taxonomy of cryptophytes still remains uncertain. IFREMER, Nantes 44000, France; MicroMar, Mer Moreover, environmental surveys revealed existence Molécules Santé, IUML - FR 3473 CNRS, University of a deep-branching clade within Cryptophyceae: Keynote and Oral Papers 54

Basal Cryptophytes. They form a sister clade to photo- Biology, University of Namur, Namur 5000, Belgium; synthetic cryptomonads. These two clades together 5Bezhin Rosko, Santec 29250, France; 6Dipartimento (cryptomonads and basal cryptophytes) are a sister di Scienze della Vita e dell’Ambiente, Università clade to the Goniomonas clade. Goniomonas is aplas- Politecnica delle Marche, Ancona 60131, Italy; tidic, has never acquired a plastid, and is currently 7Botany Department, University of Hawai‘iat considered as an ancestor to plastidic cryptomona- Mānoa, Honolulu HI 96822, United States; 8Biology dales. Upon the discovery of basal cryptophytes, the Department, University of Western Ontario, London question arose whether they constitute the most diver- N6A 5B7, Canada; 9School of BioSciences, University gent plastid-containing cryptomonad clade, or a new of Melbourne, Melbourne 3010, Australia and heterotrophic group at the base of the cryptomonad 10Department of Plant Systems Biology, VIB/Ugent, tree. Here, we combined phylogenetic and environ- Gent B-9052, Belgium mental study to address this question. The maximum likelihood phylogeny of 18S rRNA nuclear genes The trebouxiophycean genus Prasiola is an excellent confirmed placement of basal cryptophytes at the model for the study of ecological transitions, as it is base of the cryptomonad tree. We designed a specific one of the rare algal genera that includes marine, fresh- oligonucleotide probe, to detect members of this clade water and terrestrial representatives. The generitype in environmental samples by Catalysed Reported Prasiola crispa, an extremophile widely distributed in Deposition-Fluorescence in situ Hybridization cold temperate and polar regions of both hemispheres, (CARD-FISH), and to observe their basic morphol- has strong potential to serve as a good model of the ogy. None of the cells hybridized with the new probe evolution of both green algae and the land plants. We are showed chlorophyll-a autofluorescence at 590 nm, using next-generation sequencing data (Illumina tech- meaning they were aplastidic. The phylogenetic ana- nology) to obtain its complete genome sequence. lysis of 18S rRNA nucleomorph genes did not pro- Additionally, we are testing the Oxford Nannopore’s duced a sister clade to photosynthetic cryptomonads, MinION technology in order to complete the assembly suggesting that Basal Cryptophyceae had not acquired with ultra-long reads. We are presenting the first results a plastid at all. Altogether, these results indicated that of our project: complete sequences of P. crispa orga- the last aplastidic ancestor of cryptomonads could nelles, the mitochondrion (100,036 nt) and the plastid have been a basal cryptophyte, and that the engulf- genome (211,767 nt). Both have relatively low GC ment of a red algal symbiont might have been a more content (29.3% and 28.8%, respectively), as is usual recent event than when assuming radiation of the among green algae. The gene content corresponds well plastidic cryptomonads directly from Goniomonas.If with other sequenced trebouxiophyte organellar gen- confirmed upon culturing and studying a species from omes, with the only peculiarity being the presence of basal cryptophytes, it will change the view of evolu- the rpl10 gene in the mitochondrion. In the plastid DNA, tion of plastidic cryptophytes and nucleomorphs. we discovered highly reduced remnants of the ancestral plastid inverted repeats (IRs, 851 bp) that bear no genes. There are clusters of non-algal mobile elements and fi 5OR.7 unidenti ed open reading frames in both genomes; these elements appear to be organelle-specific. WHOLE GENOME SEQUENCING OF THE ANTARCTIC GREEN ALGA PRASIOLA CRISPA 5OR.8 Marie Pažoutová1 ([email protected]), Olivier De Clerck2 ([email protected]), TACKLING RAPID RADIATIONS WITH Andrea Del Cortona3 ([email protected]), CHLOROPLAST PHYLOGENOMICS IN THE Nicolas Dauchot4 ([email protected]), Jiří RHODOMELACEAE Košnar1 ([email protected]), Akira F Peters5 Pilar Díaz-Tapia1 ([email protected]), Christine A ([email protected]), Fabio Rindi6 Maggs2 ([email protected]), John AWest3 ([email protected]), Alison R Sherwood7 (asher ([email protected]) and Heroen Verbruggen3 [email protected]), David R Smith8 (dsmit242@uwo. ([email protected]) ca), Heroen Verbruggen9 (heroen.verbruggen@gmail. com) and Stephane Rombauts10 ([email protected]) 1BioCost Research Group, University of A Coruña, A Coruña 15071, Spain; 2Faculty of Science and 1Department of Botany, University of South Bohemia, Technology, Bournemouth University, Bournemouth České Budějovice 37005, Czech Republic; BH12 5BB, United Kingdom and 3School of Botany, 2Phycology Research Group, Biology Department, University of Melbourne, Melbourne 3010, Australia Ghent University, Gent B-9000, Belgium; 3Department of Plant Systems Biology, VIB/Ugent, The family Rhodomelaceae, with about 1000 species, Gent B-9052, Belgium; 4Research Unit in Plant is the most species-rich family of the red algae. Its Keynote and Oral Papers 55 great diversity is probably associated with events of genomes. Using Illumina Hi-Seq technology we rapid radiation, leading to poorly resolved phyloge- sequenced the entire chloroplast genome of repre- nies when using one or a few molecular markers. In sentatives of most genera in the Nemaliales, and fact, a comprehensive phylogeny of the entire family extracted >150 genes concatenated in a >120k has never been attempted. With the aim of construct- nucleotide alignment. Our preliminary ML phylo- ing a robust phylogeny for this family, we have used geny recovered a fully resolved tree with very high Illumina HiSeq technology to obtain chloroplast gen- bootstrap values at all nodes. The data show that omes from species representing all major clades of the the calcified Galaxauraceae family is more closely Rhodomelaceae. The phylogenetic tree is used to infer related to the exclusively uncalcified Scinaiaceae the evolution of functional morphological traits and than to the Liagoraceae sensu lato that also has the nature of the radiations. The chloroplast genomes calcified species. I will present insights into the of the Rhodomelaceae are 160-170 kb, small in size evolution of the Nemaliales and explore their compared with other red algae, showing a reduction radiation in the light of earth history. trend in the Ceramiales. The genomes are very com- pact with ca. 200 genes packed closely together. At the time of writing, the 20 available chloroplast genomes resolve the early radiation of the family, and we expect 5OR.10 to have analyzed >40 complete genomes by the time SECONDARY STRUCTURE ALIGNMENT of the conference to provide a more complete picture AND MULTIPLE OUTGROUPS CONFIRM of the early radiation of the group. Our study demon- THE MONOPHYLY OF THE DIATOM strates the power of organelle phylogenomics to unra- CLASSES USING SSU RNA GENES veling rapid radiations. However, due to the large number of species in radiations like the Linda K Medlin ([email protected]) Rhodomelaceae, further work will be needed to achieve a complete picture of the evolutionary history Oceanography, MBA, Plymouth PL1 2PB, United of the family. Kingdom Since 1993, many trees have been produced to infer the phylogeny of the diatoms. The resolution of the mono- 5OR.9 phyly of the three diatoms classes described by Medlin PHYLOGENOMICS OF THE RED ALGAL and Kaczmarska in 2004 has been controversial. ORDER NEMALIALES Medlin and Kaczmarska advocated that the monophyly of the three diatom classes could only be achieved if: 1) Joana F Costa1 ([email protected]), a secondary structure of the SSU rRNA gene was used Heroen Verbruggen2 (heroen.verbruggen@gmail. to construct the alignment and not an alignment based com) and Showe-Mei Lin3 ([email protected]) on primary structure and 2) multiple outgroups. The 1School of BioSciences, The University of Melbourne, evidence for both of these factors in recovering the Parkville VIC 3010, Australia; 2School of three clades at the class level is evaluated and reviewed. BioSciences, The University of Melbourn, Parkville The use of the secondary structure for the alignment for VIC 3010, Australia and 3Institute of Marine Biology, the SSU rRNA gene seems to be accepted but the use of National Taiwan Ocean University, Keelung Keelung multiple outgroups has only recently been tested. 20224, Taiwan Taking only bolidophytes or other heterokonts as the only outgroups never produced monophyletic clades in The order Nemaliales is part of the highly diverse single gene analysis but will recover a monophyletic red algae subclass Nemaliophycidae. Distributed mediophyte class in multi-gene analysis using BI or from subantarctic to all tropical seas it comprises ML but not using a MP analysis unless it is a weighted both calcified (in most genera of the Liagoraceae analysis. Multiple outgroups including many hetero- sensu lato and the Galaxauraceae) and uncalcified konts and certain members of the crown group radia- (Scinaiaceae) taxa. These features make it a great tion recovered monophyletic classes in single gene and fi model to study their evolutionary dynamics. multi-gene analyses. The three classes can be de ned Despite significant improvements in the higher- by clear morphological differences primarily based on level systematics and the proposal of several new auxospore ontogeny and envelope structure, the pre- genera and families in recent years based on ana- sence or absence of a structure (tube process or ster- lyses of morphology and one or two genes, the num) associated with the annulus and the presence of phylogenetic relationships among families and the cribrum in those genera with loculate areolae are genera are not fully explored. We have approached supported by molecular analyses if the proper condi- this with high-throughput sequencing of organelle tions are used. Keynote and Oral Papers 56

6. Symbiodinium as a model organism

6KN.1 6KN.2 USING SYMBIODINIUM GENOMICS TO GENETICS-BASED SYSTEMATICS AND INFORM CORAL ALGAE SYMBIOSES TAXONOMY THRUSTS SYMBIODINIUM (DINOFLAGELLATE) RESEARCH INTO THE Christian R Voolstra1 ([email protected]. 21ST CENTURY sa), Manuel Aranda1 ([email protected]), Todd C LaJeunesse2 ([email protected]) and Christopher Todd C LaJeunesse ([email protected]) J Howe3 ([email protected]) Department of Biology, Penn State, University Park 1Red Sea Research Center, KAUST University, 16802, United States Thuwal 23955, Saudi Arabia; 2Department of Biology, Pennsylvania State University, University Dinoflagellates in the Genus Symbiodinium have Park 16802, United States and 3Department of become one of the most studied micro-algal groups in Biochemistry, University of Cambridge, Cambridge science for two reasons. Their mutualisms with animals CB2 1QW, United Kingdom form the basis of coral reef ecosystems, which are threatened by climate change; and because of the many Dinoflagellates are ubiquitous marine and freshwater exciting revelations about their diversity, ecology and protists. As free-living photosynthetic plankton, they evolution gained from the use of molecular-genetic account for ~50% of the primary productivity of oceans techniques. Currently, however, most researchers study- and lakes. As photosynthetic symbionts, they provide ing animal-dinoflagellate symbioses are working and essential nutrients to corals, the architects of the ecolo- publishing without a well-established taxonomy of gically and economically hugely important reef eco- these symbionts. This has stalled basic research by redu- systems. Unfortunately, the molecular mechanisms cing the accuracy of scientific inference, prevented com- underlying this partnership are still not well under- parisons between old and new findings, and has thus stood. In an effort to better understand coral-algal sym- hampered formulation of fresh research questions. With bioses, we are currently interrogating several lines of in incorporation of phylogenetic and population genetic research. In an effort to decoding structure and function evidence, in combination with available ecological and of the coral metaorganism, we are completing sequen- physiological data, formal species designations are cing, assembly, and annotation of a coral hologenome. emerging; as the use of ‘clades’ and ‘types’ is slowly The availability of the complete gene set encoded in the discontinued. The underpinning of Symbiodinium tax- genomes of a coral animal, its dinoflagellate symbiont, onomy by a sound systematic framework opens numer- and the associated bacteria promises an unprecedented ous research possibilities, including their use as models view on the composition, structure, and function of the for the study of eukaryotic microbial dispersal, sexual coral holobiont. We are also applying deep-transcrip- recombination, adaptation and speciation. The ability to tome sequencing to multiple Symbiodinium species at resolve the prevalence and distribution of individual different taxonomic resolutions (i.e. within and strains (within each species), which are usually homo- between Clades and species) to assess transcriptomic genous inside a host colony, will lead to the evaluation and expression differences at orthologous genes. of inter-individual variation and its importance the Further, to better understand the association between response of populations to natural selection. stress tolerance of corals and molecular diversity of algal symbionts, we have developed a next-generation sequencing pipeline targeting the ITS2 rRNA gene from Symbiodinium. Besides phylogeny-based ana- 6KN.3 lyses, we developed cutoffs to delineate SYMBIODINIUM - THE FIRST Symbiodinium diversity in an OTU-based framework. DINOFLAGELLATE KNOWN TO DRIVE This allows us to compare ocean basins and coral MICROBIAL-ALGAL CALCIFICATION genera in a standardized manner. The presentation Jörg C Frommlet1 ([email protected]), Lígia Sousa1 will highlight results from these efforts and provide ([email protected]), Artur Alves1 (artur. an overview over remaining challenges in establishing [email protected]), Sandra I Vieira2 ([email protected]), Symbiodinium as a model organism for marine inverte- David J Suggett3 ([email protected]) and brate symbioses. João Serôdio1 ([email protected]) Keynote and Oral Papers 57

1Department of Biology & CESAM - Center for Brian M Hopkinson1 ([email protected]), Anna L Environmental and Marine Studies, University of Tansik2 ([email protected]), William K Fitt3 (fitt@uga. Aveiro, Aveiro 3810-193, Portugal; 2Autonomous edu) and Christof Meile4 ([email protected]) Section of Health Sciences, Center for Cell Biology 1 and Institute for Biomedicine, University of Aveiro, Marine Sciences, University of Georgia, Athens 2 Aveiro 3810-193, Portugal and 3Functional Plant 30602, United States; Marine Sciences, University of 3 Biology & Climate Change Cluster, University of Georiga, Athens 30602, United States; School of Technology Sydney, Sydney NSW 2007, Australia Ecology, University of Georgia, Athens 30602, United States and 4Marine Sciences, University of Georgia, Dinoflagellates of the genus Symbiodinium are best Athens 30602, United States known as endosymbionts of a wide range of marine invertebrates, most notably corals. Their symbiosis When engaged in a symbiotic association, the host with corals, particularly with reef-building species is of organism must supply inorganic carbon (Ci) for central importance for the entire coral reef ecosystem Symbiodinium photosynthesis, while Symbiodinium because these microalgae are important primary produ- in turn exports reduced organic carbon to the host. cers that fuel their hosts´s energy requirements, and they We have been studying Ci supply and processing in enhance coral calcification. However, besides the sym- coral-Symbiodinium associations by taking a novel biotic life style, Symbiodinium is also capable of living methodological approach that combines physiological ex hospite as a free-living form. These free-living popu- tools developed in the microalgal field and modeling. lations represent an important pool for the horizontal Through work on three species of Caribbean corals, acquisition of symbionts by coral juveniles and could we have found that ambient Ci concentrations limit play a pivotal role in maintaining coral functional diver- photosynthesis in 2 out of 3 species, and Ci is scarce sity and reef ecosystem viability and yet their biology inside the host in all species tested. Symbiodinium and ecology remain largely unexplored. Here we show isolated from these hosts show signs of Ci scarcity that free-living Symbiodinium spp. in culture commonly including high carbonic anhydrase activity and a high form calcifying bacterial-algal biofilms with naturally photosynthetic affinity for Ci. Despite this apparent associated bacteria and produce aragonitic spherulites scarcity in-hospite, the host has highly developed that encase the dinoflagellates as endolithic cells. We systems for Ci supply and Ci concentrations are high provide a description of these novel calcifying biofilms in seawater. We suggest that the host coral may inten- and the produced organomineral. Further, we demon- tionally limit Ci supply as a way to regulate the rate of strate that this calcification is driven by algal photosynth- photosynthesis over short timescales. More specula- esis but that bacterial communities also critically tively, Ci could be a suitable unit of exchange to influence the process. Another important finding was ensure that the mutualistic relationship is consistently that Symbiodinium has the ability to again vacate the respected between the partners, since Ci needs to be formed structures, suggesting that the formation of these supplied continuously to the algae and is a precursor microbialites is not an ecological dead-end but instead of the product desired by the host (organic carbon). could comprise part of a temporary endolithic life-cycle strategy. This is the first reported case of a dinoflagellate being the phototrophic driver in a calcifying microbial- algal biofilm, which demonstrates the need to re-evalu- 6OR.1 ate the role of dinoflagellates in organomineralization. GENOME ANALYSIS OF TWO Further, our findings provide evidence for an endolithic SYMBIODINIUM ISOLATES phase in the Symbiodinium life history, a phenomenon Cheong Xin Chan1 ([email protected]), Timothy G that may offer new perspectives on fundamental ques- Stephens1 ([email protected]), Edmund tions regarding the biology and ecology of these dino- YS. Ling1 ([email protected]), Sylvain Forêt2 flagellates and may also help explain how changes in ([email protected]), Kathleen Morrow3 ocean chemistry led Symbiodinium to ultimately estab- ([email protected]), David G Bourne3 lish an endosymbiotic life style. ([email protected]), Christian R Voolstra4 ([email protected]), William Leggat5 ([email protected]), David J Miller6 1 6KN.4 ([email protected]) and Mark A Ragan ([email protected]) INORGANIC CARBON SCARCITY AND LIMITATION OF SYMBIODINIUM IN 1Institute for Molecular Bioscience, and ARC Centre HOSPITE: ENVIRONMENTAL LIMITATION of Excellence in Bioinformatics, The University of OR HOST CONTROL Queensland, Brisbane QLD 4072, Australia; Keynote and Oral Papers 58

2Research School of Biology, Australian National 6OR.2 University, Canberra ACT 2601, Australia; SYMBIODINIUM THERMOPHILUM SP. NOV., 3Australian Institute of Marine Science, Townsville A THERMOTOLERANT SYMBIOTIC ALGA QLD 4810, Australia; 4Red Sea Research Center, PREVALENT IN CORALS OF THE WORLD’S King Abdullah University of Science and Technology, HOTTEST SEA, THE PERSIAN/ARABIAN Thuwal 23955, Saudi Arabia; 5ARC Centre of GULF Excellence for Coral Reef Studies, James Cook University, Townsville QLD 4811, Australia and Benjamin CC Hume1 ([email protected]), 6ARC Centre of Excellence for Coral Reef Studies, Cecilia D’Angelo1 ([email protected]), and Comparative Genomics Centre, James Cook Edward G Smith2 ([email protected]), Jamie R University, Townsville QLD 4811, Australia Stevens3 ([email protected]), John Burt4 (john. [email protected]) and Joerg Wiedenmann1 (joerg.wie Symbiodinium are symbiotic dinoflagellates that [email protected]) commonly reside in cnidarians e.g.coralsand 1Coral Reef Laboratory, National Oceanography jellyfish. A sustained loss of symbiosis between Centre, University of Southampton, Southampton Symbiodinium and corals results in coral bleach- SO14 3ZH, United Kingdom; 2Marine Biology ing and eventual death. To help guide risk man- Department, New York University, Abu Dhabi, Abu agement of reef systems in light of climate Dhabi PO BOX 129188, United Arab Emirates; change, the Sea-quence project of the Reef 3College of Life and Environmental Sciences, Future Genomics (ReFuGe) 2020 Consortium University of Exeter, Exeter EX4 4QD, United aims to generate reference genetic data for reef Kingdom and 4Marine Biology Laboratory, New York systems at the Great Barrier Reef and the Red University, Abu Dhabi, Abu Dhabi PO BOX 129188, Sea. Here we report de novo genome assemblies United Arab Emirates (coverage >30-fold) from two Symbiodinium isolates of Clades C (origin: Magnetic Island, We have recently shown that Symbiodinium from the Australia) and F (Australian National Algae nuclear ribosomal ITS2-type (clade) C3 is the preva- Culture Collection CS-156), and assess the extent lent symbiont in six common coral species along the of divergence of these genomes relative to other coast of Abu Dhabi (UAE) accounting for nearly 60% clades and to other eukaryotes. Genome size is of the analysed ITS2 sequences examined. In contrast, computationally estimated at 1.5Gbp (Clade C) clade D zooxanthellae were not detected from corals and 1.1 Gbp (Clade F), with overall G+C content in this region. Clade C symbionts have not usually ~44%. Major phylogenetic markers of nuclear been found to be exceptionally thermotolerant, but (nr28S, elf2) and organellar genes (cob, coI, have rather been defined as a cosmopolitan, generalist psbA, cp23S) were recovered. Of the 458 con- clade. However, recent advances in phylotyping of ncr served eukaryote proteins across six model organ- zooxanthellae using chloroplast sequences (psbA ) isms (in CEGMA), we recovered 176 (38%) in suggest that several lineages within ‘clade C’ repre- Clade C, 149 (33%) in F; the corresponding num- sent distinct Symbiodinium species. Through analysis ncr bers are higher at 295 (64%) and 267 (58%) when of psbA sequences of C3-type zooxanthellae along proteins of the chlorophyte Chlamydomonas rein- >1000 km of coastline in the Persian/Arabian Gulf hardtii and apicomplexan Toxoplasma gondii and the Gulf of Oman we propose that the ITS2-type were included in the analysis. This observation C3 zooxanthellae from Gulf corals represent a new suggests high divergence between genomes of species. In addition, monitoring the seasonal domi- Symbiodinium and other eukaryotes. Genome nance of zooxanthellae types in individual colonies of mapping using published transcriptomes (of six coral species over three years we demonstrate that clades A through D) shows substantial divergence despite some species-specific variability in seasonal among different clades, with mapped coding composition of the zooxanthellae complement, this regions having higher G+C content (~50%). Our species remains the prevalent symbiont of corals findings support the established inter-clade phylo- from the Southern Gulf, the world’s hottest sea. genetic relationships of Symbiodinium, and suggest a trend of genome reduction from the basal lineage (Clade A; estimated size ~3Gbp) through to the more recently diverged lineages of Clades 6OR.3 C and F. These genome data provide an excellent TURNING UP THE HEAT ON SYMBIODINIUM analysis platform for testing numerous biological CELL CYCLE ANALYSIS hypotheses related to algal evolution and Lisa Fujise1 ([email protected]), David adaptation. J Suggett1 ([email protected]), Jörg C Keynote and Oral Papers 59

Frommlet2 ([email protected]), João Serôdio2 (jsero Differentiation between motile stages (MS) and non- [email protected]) and Peter J Ralph1 (Peter.Ralph@uts. motile stages (NMS) are common transitions in the edu.au) life history of dinoflagellates, including the formation of coccoid stage within symbiotic hosts. 1Functional Plant Biology & Climate Change Cluster, Dinoflagellates have some of the largest known gen- University of Technology Sydney, Sydney 2007, omes in the eukaryotes but counter-intuitively have Australia and 2Department of Biology and CESAM - the lowest known chromosomal-to-protein ratios and Center for Environmental and Marine Studies, nucleosomes could not be detected in their chromo- University of Aveiro, Averio 3810-193, Portugal somes by conventional assays. It is only recently that genomic studies revealed the presence of dinoflagel- Dinoflagellates of the genus Symbiodinium are tied to late core histones (d-histones) and nucleosome- an endosymbiotic life style with reef forming corals, assembly factors in dinoflagellates, amid very low but through a transient free-living life history phase. expression levels. We were able to assemble nucleo- Cell cycle as an endosymbiont is controlled by the somes in vitro and CHIP assays also suggested host coral and typically arrested in the G1 phase (pre- nucleosome formation in vivo. We developed large- paration for DNA replication) whereas when in free- scale preparations of coccoid stage from a hetero- living (cultured) Symbiodinium cycle across G1 to S trophic dinoflagellate as a model system to investigate (DNA synthesis) to G2/M phases (pre-mitotic gap and the histone modifications during NMS to MS transi- mitosis) over 24 h, in regulation of cell proliferation. tion. We observed differential expression in the d- However, how this cell cycle is potentially influenced histone proteins, and specific modifications of d-his- by stressors is unknown and represents a key uncer- tones are associated with the NMS-MS transitions. tainty as to how this organism can respond to environ- Preliminary CHIP-PCR experiments also suggested mental change. Heat stress in particular impacts that d-histones are predominantly associated with symbiont fitness but how it impacts upon life history actively transcribing genomic regions. dynamics is as yet unresolved. We therefore initially optimised a protocol suitable for cell cycle analysis of Symbiodinium, which was then applied to a large representation of Symbiodinium ITS2 type (clades A, 6OR.5 B, C, D, and F) and hence account for any possible THE BIOGEOCHEMISTRY OF role of phylogeny upon subtle variations in cell cycle SYMBIODINIUM FUNCTION AND progression. This exercise demonstrated that there COMPETITION were differences in DNA histogram forms across the strains, for example differences in G2/G1 ratios, coef- David M Baker ([email protected]) ficient variations of G1 peak and the abundances of S and G2/M phase. We subsequently performed a heat School of Biological Sciences, Department of Earth stress experiment on a subset of cultures spanning 5 Science, Swire Institute of Marine Science, The clades, which showed the reduction of cell cycle pro- University of Hong Kong, Hong Kong N/A, China gression throughout the day and did not show the diel change of the phase fractions. We discuss how this With one of the largest known eukaryotic genomes, observation particularly impacts Symbiodinium cell Symbiodinium possess the genetic resources for an proliferation through ecological fitness in nature. impressive portfolio of biochemistries. Many of these blueprints code for essential parts to nitrogen metabolism. This may be a result of the ocean’s relative oligotrophy over deep time. Today, however, global 6OR.4 conditions are rapidly changing and so too has the relationship between Symbiodinium and their inverte- HISTONE MODIFICATIONS DURING brate hosts. In this talk, I will present several lines of REVERSIBLE TRANSITIONS BETWEEN evidence from eco-physiological and stable isotope MOTILE AND NON-MOTILE STAGES OF investigations that show: 1) that Symbiodinium carbon DINOFLAGELLATES and nitrogen assimilation rates are sensitive to tempera- JTY Wong1 ([email protected]) and SP Wen2 (boti ture, 2) that different clades/species have competitive [email protected]) advantages for resource acquisition, and 3) that across the diversity of host taxa, the predominant currency of 1Division of Life Science, Hong Kong University of symbiosis is growth-limiting nitrogen. Taken together, Science and Technology, Kowloon NA, Hong Kong these observations support the hypothesis that and 2Nanoscience and Technology Program, Division Symbiodinium mutualisms evolved to overcome severe of Life Science, Kowloon NA, Hong Kong nutrient limitation in the tropical seas. Keynote and Oral Papers 60

6OR.6 Delaware 19985, United States; 3Climatic Change Cluster (C3), University of Technology, Sydney, LOCAL ADAPTATION OF SYMBIODINIUM Sydney NSW 2007, Australia; 4Biological and THERMOPHILUM-ASSOCIATED CORALS TO Environmental Science and Engineering, KAUST, THE EXTREME ENVIRONMENT OF THE Thuwal 2246-WS18, Saudi Arabia; 5School of Marine PERSIAN/ARABIAN GULF Science and Policy, University of Delaware, Joerg Wiedenmann ([email protected]. Delaware 19958, United States and 6Biological ac.uk), Cecilia D’Angelo (C.D’[email protected]) Department, University of Essex, Colchester CO4 and Benjamin CC Hume ([email protected]) 3SQ, United Kingdom

Coral Reef Laboratory, University of Southampton, Climatic change is causing dramatic changes to the Southampton SO143ZH, United Kingdom stability of coral reefs worldwide. Studies have particularly focused on the distribution and physiological Symbiodinium thermophilum is the prevalent coral flexibility of coral-algal symbioses over latitudinal symbiont in the southern Persian/Arabian Gulf gradients in an attempt to understand how coral reefs (PAG). This recently described species represents a will potentially respond to the continued stress caused promising model for heat tolerant coral symbionts by climate change. It is clear that corals can flexibly since PAG corals associated with S. thermophilum associate with stress tolerant symbionts (genus endure summer temperatures of up to 35 degrees Symbiodinium) when persistently living in high tem- Celcius on a regular basis. However, Symbiodinium- perature environments or during times of anomalous coral associations in the PAG cope also with the high- thermal stress; however, the physiological response of est salinity levels (often 42-44) reported globally for coral-algal symbioses over latitudinal gradients and coral reef ecosystems. The elevated salinity of PAG the very different thermal regimes throughout the waters results from the restricted water exchange with largely understudied region of the Red Sea is still the adjacent Gulf of Oman and the wider Indian unknown. We therefore contrasted the thermal toler- Ocean, shallow depths, high evaporation rates and ances of coral-algal symbiosis in Thuwal, Saudi limited freshwater input. The resulting halocline cir- Arabia versus Hurghada, Egypt where the seasonal culation is sustained by a net inflow of surface water thermal maximum thresholds are very different (32° into the PAG and limited outflow of heavier, more C and 29°C, respectively). The abundant coral species saline bottom waters. While it is well established Pocillopora damicornis was particularly interesting that local adaptions to prevailing environmental con- because thermal stability was different between popu- ditions shape the distribution of many terrestrial lations inhabiting the two locations despite associat- plants, it is unknown to which extend adaptations, ing with the same clade C ITS2 symbiont: specifically, for instance to high local salinity, affect also the spread heat-stress induced declines of photochemical opera- of algal coral symbionts. Here we demonstrate that tion was only observed form the naturally warmer local adaptations of Symbiodinium thermophilum- more southerly red sea site (Saudi). These physiolo- associated PAG corals shape the heat stress tolerance gical differences reveal the importance of adaptation of this symbiotic partnership. I will discuss our find- to local environmental conditions yet contradict pre- ings and their implications for coral reef survival and vious studies that show populations of the same sym- management under the pressure of climate change. biont type living at high temperatures are better adapted to thermal stress. As such, this symbiosis may be living near its thermal maximum on the reefs 6OR.7 near KAUST and/or there may be further genetic differentiation for the host and symbiont. Further PHYSIOLOGICAL RESPONSE OF field surveys at five sites along Egyptian coast from SYMBIODINIUM POPULATIONS ADAPTED the northern Gulf of Aqaba to southern Egypt (1000 TO DIFFERENT THERMAL REGIMES IN THE km) are discussed and reveal species-specific differ- RED SEA ences in coral/symbiont specificity over this latitudi- Eslam Osman1 ([email protected]), Tye nal range. Pettay2 ([email protected]), David J Suggett3 (david. [email protected]), Christian R Voolstra4 (christian. [email protected]), Mark E Warner5 (mwar 6OR.8 [email protected]) and David Smith6 (djmitc@essex. NANOSIMS ISOTOPIC IMAGING - ac.uk) DECIPHERING THE NATURE OF CORAL- 1 SYMBIONT METABOLIC INTERACTIONS Biological Department, University of Essex, Colchester CO2 7EU, United Kingdom; 2School of Thomas Krueger1 (thomas.krueger@epfl.ch), Marine Science and Policy, University of Delaware, Christoph Kopp1 (christophe.kopp@epfl.ch), Isabelle Keynote and Oral Papers 61

Domart-Coulon2 ([email protected]), Maoz Fine3 Stéphane Roberty1 ([email protected]), Benjamin ([email protected]) and Anders Meibom1 (anders. Bailleul2 ([email protected]), Nicolas Berne3 meibom@epﬂ.ch) ([email protected]), Fabrice Franck3 ([email protected]) and Pierre Cardol3 1Laboratory for Biological Geochemistry, École ([email protected]) polytechnique fédérale de Lausanne, Lausanne 1015, Switzerland; 2MCAM UMR7245 CNRS-MNHN, 1Marine Department, Centre Scientiﬁque de Monaco, Muséum National d’Histoire Naturelle, Paris 75005, Monaco MC-98000, Monaco; 2Botany Institute, France and 3The Interuniversity Institute for Marine University of Liege, Liege B-400, Belgium and 3Botany Sciences, Eilat 88000, Israel Institute, University of Liege, Liege B-4000, Belgium

The ability of endosymbiotic Symbiodinium to fixinor- The ecological success of symbiotic cnidarians (reef ganic nutrients and their translocation to the coral host is building-corals and sea anemones) relies on the sym- considered a key element for the growth of coral reefs in biosis between cnidarians and photosynthetic dinofla- tropical coastal waters and has been a fundamental gellates of the genus Symbiodinium. Photosynthetic research topic for over 50 years. With pulse-chase organisms have evolved various photoprotective and experiments using stable isotopes and combined TEM regulatory mechanisms to cope with changing and and NanoSIMS ultrastructural and isotopic analyses it is high light intensities, but the nature and relative ampli- now possible to visualize and quantify the fixation, tude of these mechanisms is still a matter of debate in translocation, and turnover of essential elements such Symbiodinium. Few studies showed that molecular as carbon and nitrogen with unprecedented subcellular oxygen (O2) can be an efficient electron sink during resolution. With these techniques we have monitored the photosynthesis in Symbiodinium, with an O2 uptake assimilation of 15Nnitrate,15N ammonium, and 13C capacity that could represent up to half the maximum bicarbonate in the coral Pocillopora damicornis.These O2 evolution. In addition, members of clade A studies have revealed dynamic intra-symbiont storage of Symbiodinium were proposed to possess enhanced assimilated nitrate and ammonium in the form of uric capabilities for alternative photosynthetic electron acid crystals, and the formation of lipid droplets and flows. In this work, the amplitude of photosynthetic starch granules in the symbiont and their subsequent alternative electron flows to oxygen (chlororespira- remobilization. Carbon translocation toward the coral tion, Mehler reaction, mitochondrial respiration) and gastrodermal lipid droplets was detected within 15 PSI cyclic electron flow was investigated in min. Moreover, glycogen granules in the coral tissue Symbiodinium strains belonging to different Clades were found to be an important sink for translocated (A, B and F). Joint measurements of oxygen evolu- carbon. This work has now been extended to the related tion, PSI and PSII activities allowed us to demon- pocilloporid species, Stylophora pistillata,withthe strate that photoreduction of oxygen downstream PSI important addition of heterotrophy (feeding the coral by the so-called Mehler reaction is the main alterna- with dual-labelled brine shrimps) to contrast the fate tive electron sink at the onset and steady state of and timeframes of heterotrophic vs. autotrophic (15N photosynthesis in all strains1. This mechanism in nitrate/13C bicarbonate) nutrient uptake under natural Symbiodinium sustains significant photosynthetic conditions and environmental stress due to elevated electron flux under high light, thus acting as a photo- water temperatures. The in situ spatial data provided protective mechanism and modifying the ratio of by NanoSIMS allow us for the first time to address ATP/NADPH to match the requirements of carbon questions that cannot be answered by traditional bulk reduction. At higher temperature (26 to 33°C), the measurements, such as: (1) the influence of local sym- amplitude of Mehler reaction was still significantly biont densities on individual Symbiodinium assimilation increased while the capacity of enzymes responsible rates, (2) metabolic capabilities of different symbiont for superoxide detoxification largely decreased. This ITS2 types in hospite, and (3) the effect of changes in imbalance generated twice more ROS than during intracellular host and symbiosome pH on individual the treatment at 26°C, suggesting that under condi- symbiont productivity. tions known to induce coral bleaching, the photoprotective role of Mehler reaction can no longer be maintained, at least at short term. 6OR.9 CRITICAL ROLE OF OXYGEN 6OR.10 PHOTOREDUCTION DOWNSTREAM OF PSI IN SYMBIODINIUM: PHOTOPROTECTION, METABOLIC RESPONSES TO CHRONIC ENERGETIC ADJUSTEMENT AND ROS NUTRIENT STRESS DIFFER BETWEEN PRODUCTION SYMBIODINIUM PHYLOTYPES Keynote and Oral Papers 62

Tom D Hawkins ([email protected]) and Mark E increased in both types and was driven by increasing Warner ([email protected]) PSII functional absorption cross section. Changes in autotrophic capacity (measured as 14C-labelled bicarbo- College of Earth, Ocean and Environment, University nate-fixation) mirrored those of PSII efficiency, with of Delaware, Lewes 19958, United States 14C-fixation rates declining more dramatically in response to nutrient limitation in Symbiodinium A13. Dinoflagellates of the genus Symbiodinium areadiverse Changes in mitochondrial activity (quantified as the group of microalgae that play a critical role in the activity of citrate synthase [CS], the key “gatekeeper” energetics of coral reefs. Here, we report differences enzyme of the citric acid cycle) and reactive nitrogen between two Symbiodinium phylotypes (ITS2-types and -oxygen generation (RNS and ROS, respectively) A20 and A13) in their responses to chronic nutrient also differed between the two phylotypes. CS activity stress. During a five-week experiment in which batch generally declined following culture inoculation, but cultures were grown in initially nutrient-replete- (f/2 then increased in type A20 under nitrate- and phosphate 2- media; 882 µM NO3-, 36.2 µM PO4 ) or low-nutrient starvation. In type A13, CS activity remained relatively 2- media (22.1 µM NO3-, 0.9 µM PO4 ), we observed unchanged. Cellular RNS content – quantified using divergent cellular stress responses. Photosystem II (PSII) flow cytometry – increased 4-fold in both types under efficiency declined for both types, but did so earlier (by low-nutrient conditions, but significant ROS synthesis 3-5 days) in type A13. Non-photochemical quenching was seen only in type A20. These results will be dis- (NPQ) of chlorophyll a fluorescence increased corre- cussed in the context of the dynamic stability of coral- spondingly, and was more dramatic in type A20. Symbiodinium associations, in which the partitioning of However, these increases were transient as NPQ col- fixed carbon, as well as RNS- and ROS synthesis, play lapsed following prolonged exposure (> 3 weeks) to key roles while Symbiodinium remain in unbalanced low-nutrient conditions. PSII electron transport rate growth. Keynote and Oral Papers 63

7. Molecular Cell Biology

7KN.1 Cell and Developmental Biology, University of UNEXPECTED DIVERSITY OF Massachusetts Medical School, Worcester, MA 01655, CRYPTOCHROME PHOTORECEPTORS United States FROM ALGAE Cilia and eukaryotic flagella (terms here used inter- Tilman Kottke ([email protected]) changeably) occur in organisms ranging from unicellular protists to humans, where they are present in Physical and Biophysical Chemistry, Bielefeld many tissues. Chlamydomonas has numerous advan- University, Bielefeld 33615, Germany tages that have made it a favorite model system for Cryptochromes act as sensory blue light receptors investigating these important cell organelles. Because cilia have been highly conserved throughout evolu- in bacteria, fungi, plants, and insects. They non- fl covalently bind flavin as a chromophore. In algae, tion, studies of the Chlamydomonas agellum have the roles of several different cryptochromes have contributed greatly to our knowledge of the basic been identified in the recent years. Some of these biology of ciliary assembly and function. More cryptochromes group to established subfamilies recently, Chlamydomonas has provided important such as CPH1 from Chlamydomonas reinhardtii, insights into the role of cilia in human health and a member of the plant cryptochromes. Others are disease, including primary ciliary dyskinesia, cystic distinguished by their position in the phylogenetic kidney disease, blindness, and hydrocephalus. Cilia are built by a process called intraflagellar transport tree or by their molecular properties. The animal- fi like cryptochrome (aCRY) from C. reinhardtii has (IFT), which was rst observed in Chlamydomonas and involves the active movement of large protein been demonstrated to respond to yellow and red fl light as well as to blue light in vivo,which complexes from the base to the tip of the agellum expands the role of cryptochromes as blue light and then back to the cell body. These complexes carry receptors to the other regions of the visible spec- cargos necessary for the assembly and maintenance of trum. Moreover, the cryptochrome CryP from cilia. Studies of IFT in Chlamydomonas led to the Phaeodactylum tricornutum isamemberofa discovery that polycystic kidney disease, the most new subfamily of cryptochromes. The response of common life-threatening inherited disease in humans, algal cryptochromes to light differs also in vitro is most often caused by defects in receptors displayed and has been studied by electronic and vibrational on non-motile primary cilia, which function as cellular spectroscopy. Different redox states of flavin are antennae receiving signals from the environment and involved in the photoreactions. In CPH1, a reac- relaying those signals back to the cell body. Other tion from oxidized to neutral radical takes place. In human disorders, including blindness and another contrast, aCRY has been postulated to undergo a cystic kidney disease, nephronophthisis, are caused reaction from the neutral radical to the fully by defects in conserved proteins located at the ciliary reduced state in vivo [Beel et al. Plant Cell, 24, transition zone, a little-studied region between the 2992.]. This model is in agreement with a change ciliary basal body and ciliary shaft. Studies of these in conformation of the receptor induced by this proteins in Chlamydomonas have revealed that the transition zone functions as a selective “flagellar photoreaction only [Spexard et al. 2014, ” Biochemistry 53, 1041.]. CryP forms a stable radi- pore or gate that keeps cell body proteins out of the cal state of flavin in the dark, which has implica- cilium while allowing ciliary proteins into the cilium. tions for its role as a receptor in diatoms [Juhas et al. 2014, FEBS J. 281, 2299]. 7KN.3 GREEN ALGAE DIVIDING BY MULTIPLE FISSION – POTENT TOOL (NOT ONLY) FOR 7KN.2 CELL CYCLE STUDIES THE CHLAMYDOMONAS FLAGELLUM AS A Kateřina Bišová ([email protected]), Monika Hlavová MODEL FOR HUMAN DISEASE ([email protected]), Mária Čížková ([email protected]) and Zoltán Turóczy George B Witman ([email protected]) ([email protected]) Keynote and Oral Papers 64

Laboratory of Cell Cycles of Algae, Institute of specific manner. This gives reason to believe that tran- Microbiology CAS, Trebon 37981, Czech Republic scriptome pattern of each cell type could change differentially in response to environmental light. Comparison Green algae dividing by multiple fission are a diverse ofthegeneexpressionprofiles of the reproductive and group formed by species from unrelated genera. They somatic cells reported revealed that distinct cell-type are connected by a common feature: mother cell under specific light signaling pathways underlying gene optimal growth conditions divides into more than two expression modulate appropriate transcript regulation daughter cells. This organization of cell cycle represents in response to light. Blue light tends to be effective to a potent evolutionary strategy allowing them to exploit accumulate transcripts in the somatic cells; while red maximum of sun light during day for growth without light leads to accumulate transcripts predominantly in constraints from the cell cycle related processes. The the reproductive cells. Thus, the data show that each cell best developed model organism is Chlamydomonas type has its own genetically predefined light signaling reinhardtii but other representatives include biotechno- pathways to modulate expression of genes involved in logically important algae such as Chlorella sp. and various cellular and metabolic processes including cir- Scenedesmus sp. Here, we will summarize the principles cadian rhythms and photosynthesis in response to envir- governing the cell cycle regulation in algae dividing by onmental light. multiple fission. Further, we will present an example of possible exploitation of the cell cycle mutants for the study of coordination of cell cycle and response to DNA 7OR.2 damage. This work was supported by the GA CR (grant no. 15-09231S), CAS (grant no. M200201205) and by THE CIRCADIAN CLOCK IN THE DIATOM PHAEODACTYLUM TRICORNUTUM projects Algaman and Algain. Rossella Annunziata1 ([email protected]), Antonio E Fortunato1 ([email protected]), 7OR.1 Soizic Cheminant Navarro1 (soizic.cheminant_na- [email protected]), Marie JJ Huysman2 (mahuy@psb. CELL-TYPE SPECIFIC PHOTORECEPTORS 3 vib-ugent.be), Dimitri Petroutsos (dimitris.petrout- AND ASSOCIATED LIGHT-SIGNALING 4 [email protected]), Tore Brembu ([email protected]), Per PATHWAYS IN THE MULTICELLULAR ALGA 4 4 VOLVOX CARTERI Winge ([email protected]), Bones Atle (atle. [email protected]), Giovanni Finazzi3 (giovanni. Arash Kianianmomeni ([email protected]) fi[email protected]), Marco Cosentino Lagomarsino1 ([email protected]) and Angela Department of Cellular and Developmental Biology Falciatore1 ([email protected]) of Plants, University of Bielefeld, Bielefeld 33615, Germany 1Laboratory of Computational and Quantitative Biology, Sorbonne Universités, UPMC Univ Paris 06, Photosynthetic organisms, e.g., plants including green UMR 7238, Paris 75006, France; 2Department of algae, use a sophisticated light-sensing system, com- Plant Systems Biology, VIB, Gent 9052, Belgium; posed of primary photoreceptors and additional down- 3Laboratoire Physiologie Cellulaire et Végétale, stream signaling components, to monitor changes in the CNRS, UMR 5168, Grenoble 38041, France and ambient light environment towards adjust their growth 4Department of Biology, Norwegian University of and development. Although a variety of cellular pro- Science and Technology, Trondheim 7491, Norway cesses, e.g., initiation of cleavage division and final cellular differentiation, have been shown to be light- The majority of living organisms evolved circadian regulatedinthegreenalgaVolvox carteri, little is clocks, sophisticated mechanisms that synchronize known about the underlying light perception and signal- cells with the environmental periodic cues. Although ing pathways. This multicellular alga possesses at least well studied in terrestrial plants and animals, only a 13 photoreceptors, i.e., one phototropin (VcPhot), one few examples of circadian clocks have been described UV-B photoreceptor (VcUVR8), four cryptochromes in marine organisms. Diatoms have exceptional adap- (VcCRYa, VcCRYp, VcCRYd1 and VcCRYd2) and tation capacities and exhibit circadian behaviors in seven members of rhodopsin-like photoreceptors natural environments. Interestingly, no orthologous (VR1, VChR1, VChR2, VcHKR1, VcHKR2, of known circadian clock components have been VcHKR3 and VcHKR4), which display distinct light- found in the sequenced genomes, suggesting the exis- dependent chemical processes based on their protein tence of a diatom specific clock. In order to reconstruct architectures and associated chromophores. The study diatom timing mechanisms, we completed high-reso- of Volvox photoreceptors was almost always accompa- lution physiological and transcriptomic analyses of nied by questions regarding their cell-type specificfunc- Phaeodactylum tricornutum cells grown in diurnal tions, because they are mostly expressed in a cell-type light cycles and free-running conditions. We identified Keynote and Oral Papers 65

24 genes showing robust rhythmic expression upon known factors involved in desiccation tolerance the different treatments, including putative clock (LEA, ERD), energy production, ROS metabolism inputs, oscillators and outputs, demonstrating a circa- and enzymes involved in biosynthesis of raffinose dian regulation of transcription. Using a mathematical family oligosaccarids (RFO), however many with- approach, we selected the most rhythmic out known function. 330 transcripts were comple- Transcription Factors (TFs) and explored their func- tely suppressed. In Zygnema sp. from polar and tion by gene knockdown and over-expression. This alpine habitats desiccation tolerance was only allowed the identification of a first clock component, a observed in mature cultures that form akinetes, in bHLH-PAS TF, whose deregulation causes growth which Y II dropped to zero within 5-7 h at ~83% impairment, loss of circadian gene expression and a RH. The transcriptomic analysis in Zygnema sp. negative feedback loop effect on its own transcription. (SAG 2419) is underway. We analyzed the fatty Further characterizations of these and other TF acid composition in Zygnema B, C and E. In all mutants will allow unraveling the circadian clock samples the major fatty acids found were oleic and architecture and its adaptive significance in diatoms. linoleic acid, except in young cultures that also contained palmitic and linolenic acids. We found significant differences in the fatty acid composition 7OR.3 between young cultures and all other samples, however hardly any impact of the desiccation/ DESICCATION TOLERANCE IN recovery experiment. We conclude that desiccation STREPTOPHYTIC GREEN ALGAE: NEW tolerance occurs in both algal classes, but different INSIGHTS FROM TRANSCRIPTOMICS AND mechanisms (i.e. desiccation tolerance only after FATTY ACID METHYL ESTER (FAME) maturation in Zygnema) may be involved. ANALYSIS Andreas Holzinger1 ([email protected]), Martina Pichrtová2 ([email protected]), 7OR.4 Erwann Arc1 ([email protected]), Wolfgang 3 THE STRUCTURE AND FUNCTION OF Stöggl ([email protected]), Ilse 4 COCCOLITH ASSOCIATED Kranner ([email protected]) and Burkhard 5 POLYSACCHARIDES: IMPLICATIONS FOR Becker ([email protected]) THEIR ROLE IN CALCIFICATION 1Instiute of Botany, Univeristy of Innsbruck, Charlotte Elizabeth Walker1 ([email protected]), Innsbruck 6020, Austria; 2Department of Botany, Colin Brownlee1 ([email protected]), Toby Tyrrell2 Charles University in Prague, Prague 12801, Czech ([email protected]) and Glen Wheeler1 Republic; 3Instiute of Botany, University of Innsbruck, ([email protected]) Innsbruck 6020, Austria; 4Institute of Botany, University of Innsbruck, Innsbruck 6020, Austria and 1Cellular and Molecular Biology, Marine Biological 5Botanical Institute, University of Cologne, Cologne Association, Plymouth PL12PB, United Kingdom and 50674, Germany 2Ocean and Earth Science, University of Southampton, Southampton SO14 3ZH, United Terrestrial green algae frequently experience desic- Kingdom cation. We investigated changes to the transcriptome in Klebsormidiophyceae and fatty acid Coccolithophores are globally distributed, unicellu- composition in Zygnematophyceae upon desicca- lar marine algae belonging to the phylum tion stress. At ~ 83% relative humidity (RH) the Haptophyta. Characterised by internally produced, effective quantum yield of photosystem II (Y II, intricate calcite liths found on the cell surface, they PAM 2500) dropped to zero between 4.5 and 7 are biogeochemically important due to their role in hours in Klebsormidium crenulatum (SAG 2415). the transfer of carbon from the upper waters to The cells were able to recover 95% of the initial depth. Research has focused on the mechanisms values within 40 min. When desiccated over silica behind calcification, but exactly how and why gel (final RH ~10%), Y II dropped to zero within they calcify is still unknown. During lith production 40-50 min and no immediate recovery of Y II was in the unique Golgi-derived coccolith vesicle, poly- observed. We analyzed the transcriptome under saccharides are simultaneously produced and moist and desiccated (2.5 h silica gel, RH ~ extruded. These coccolith-associated polysacchar- 10%) conditions using RNAseq. The reference ides (CAPs) have been shown to play a role in transcriptome includes about 24,183 sequences the regulation of calcium carbonate precipitation; (1.5 million reads, 636 million bases). Over 7000 and therefore calcification. In this investigation we transcripts changed upon desiccation, 169 tran- looked at a range of species of coccolithophores scripts were 10 fold upregulated, including and their CAPs by direct observation and Keynote and Oral Papers 66 biochemical analysis. The results show there are but also in the compartments surrounded by the outer clear structural differences between species’ CAPs, plastid membranes. giving rise to questions of differences in role. Here we present evidence that suggests CAPs are involved in the organisation of the coccosphere, 7OR.6 demonstrating that there is more to their function INVESTIGATING SIGNAL DOMAINS AND than previously hypothesised. TRANSLOCASES INVOLVED IN PROTEIN IMPORT INTO EUGLENID PLASTID Anna Vanclova ([email protected]), Anna 7OR.5 Karnkowska ([email protected]), Naoji Yubuki ([email protected]) and Vladimir CHARACTERISATION OF NUCLEOTIDE TRANSPORTER PROTEINS IN COMPLEX Hampl ([email protected]) PLASTIDS Department of Parasitology, Charles University in Lili Chu ([email protected]) Prague, Prague 2 128 44, Czech Republic

Biology, University of Konstanz, Konstanz 78467, Euglenophytes are inner group of euglenids character- Germany ized by photoautotrophy and presence of green three- membrane-bound secondary plastid derived from pra- In contrast to land plants, in diatoms the de novo sinophyte ancestor. Secondary and higher plastids are biosynthesis of nucleotides takes place in the cytosol, present in many unrelated protist groups yet their pro- which means that all nucleotides required in the plas- tein targeting seems to have developed in a remarkably tids have to be transported across the four membranes convergent way, reflecting the import system already surrounding the complex plastid. The genome of the present in the primary plastid and the general endo- diatom Phaeodactylum tricornutum encodes six symbiont-host system features. Components of the nucleotide translocator (NTT) isoforms. This unu- TOC/TIC system of the innermost membranes, which sually high number of NTT genes might enable the are homologous to primary plastid envelope, have been transport of newly synthesised nucleotides into the identified in most secondary and higher algae at least stroma to supply the constant demand for nucleotides, on the genomic level. Import across the additional e.g. for DNA- or RNA-synthesis. In previous works, membrane(s) often proceeds through ER or ER-derived we characterised two diatom NTTs (NTT1 and pathways. NTT2), both transporters are most likely targeted The presence of targeting sequence in majority of into the innermost plastid envelope membrane. transcripts destined to plastid suggests that TOC/TIC- NTT1 is a specific adenine nucleotide transporter, based system mediates protein transport across the which exploits a proton gradient for net import of inner membranes of euglenid plastid. Both complexes ATP into the stroma via symport of protons. NTT1 are probably reduced and/or divergent in primary struc- phylogenetically resembles land plant NTTs, which ture because no component has been identified yet. however differ in their transport activity. NTT2 phy- Import across the third membrane is known to involve logenetically resembles bacterial NTTs and accepts a vesicles whose recognition and fusion mechanism broad range of substrates (nucleoside triphosphates remains unclear. Using HMM-based algorithm we and their deoxy-forms) which are counter-exchanged found in silico evidence for Tic21 and Tic32 subunits against ATP. Here, we present results of the character- in Euglena gracilis transcriptome. Both subunits were isation of the P. tricornutum NTT5, which, in contrast also found in Eutreptiella gymnastica (marine species, to NTT1 and NTT2, is not located in the innermost phylogeneticaly distant from E. gracilis), Tic32 was plastid membrane, but instead is targeted to the outer- found in Euglena longa (secondarily heterotrophic most or second outermost plastid membrane. species closely related to E. gracilis) and Tic21 in Biochemical measurements show that NTT5 appar- Rapaza viridis (mixotrophic euglenid, sister taxon to ently acts in an antiport mode and is able to transport a all other euglenophytes). Results of further in silico broad substrate spectrum consisting of tri-, di- and analyses of these proteins and localization experiments mono-phosphorylated adenosine and guanosine in E. gracilis using specifically designed peptide anti- nucleotides as well as dATP and dGTP. Such a bodies will be presented on the conference. We also broad substrate spectrum has not yet been described characteried N-terminal regions of putative plastidal for any NTT. Comparative sequence analyses indicate proteins of E. gracilis and other euglenophytes men- that nucleotide transporters resembling NTT5 are tioned above, namely their length, sequence, hydro- exclusively found in diatoms. Taken together, our phobicity and amino acid composition, in order to results show that diatoms apparently depend on a design pipeline for prediction of plastid targeting regulated supply of nucleotides not only in the stroma, sequences in euglenids. Keynote and Oral Papers 67

7OR.7 pharmaceutics, biofuel production and nanotechnol- ogy. Despite their major ecological importance and FUNCTION OF THE CONTRACTILE their potential commercial value, many mysteries VACUOLE IN CHLAMYDOMONAS:A about the mechanisms that control the diatom cell SYSTEMS BIOLOGY APPROACH and life cycle still remain. In particular, their ability Burkhard Becker ([email protected]) and Karin to live and dominate in rapidly changing and some- Komsic-Buchmann ([email protected]) times harsh environments, suggests that diatoms have evolved specific strategies to adapt to and proliferate Department of Biology, University of Cologne, Köln in highly fluctuating conditions. Unraveling the reg- 50674, Germany ulatory mechanisms that underlie their unique life cycle strategies will be of crucial importance to under- Systems Biology aims to model and discover emer- stand diatom ecology and evolution and to further gent properties of biological systems. We applied a exploit their industrial potential. Our main research systems biology approach to osmoregulation and con- focus is to gain insights into the molecular and genetic tractile vacuole function in Chlamydomonas. We will mechanisms that control the diatom cell cycle. In this present a model of CV function/osmoregulation in presentation I will highlight our latest findings that Chlamydomonas. The model incorporates cellular demonstrate how diatoms use a common eukaryotic growth as well as osmotic stress and allows prediction base of cell cycle regulatory components complemen- of the relative changes in metabolite/protein concen- ted with some novel diatom-specific features to con- trations upon environmental challenges. The model trol their cell division, including the role of the predicts that only small changes in mRNA/protein diatom-specific cyclin at the light-dependent G1 abundance are required for adaptation of a checkpoint, and the ambiguous cyclin-dependent Chlamydomonas cell to different osmotic conditions. kinase CDKA2 during mitosis. Using quantitative expression analysis and the Illumina RNA-seq platform we tested the predictions of the model experimentally. Transcriptome analyses of Chlamydomonas cells were carried out after adap- 7OR.9 tation to different osmotic stress conditions. We then A RECEPTOR-LIKE KINASE, RELATED compared the relative abundances of mRNAs for pro- WITH CELL WALL SENSOR OF HIGHER tein complexes known to be involved in CV function PLANTS, IS REQUIRED FOR SEXUAL as determined by transcriptome analyses, with the REPRODUCTION IN THE UNICELLULAR predictions from our model. Generally, experimental CHAROPHYCEAN ALGA, CLOSTERIUM and theoretical data agreed very well, however, there PERACEROSUM-STRIGOSUM-LITTORALE are notable exceptions. The relevance of these results COMPLEX for our understanding of osmoregulation/CV function Hiroyuki Sekimoto ([email protected]) in Chlamydomonas will be discussed. Department of Chemical and Biological Sciences, Faculty of Science, Japan Women’s University, Tokyo 7OR.8 1128681, Japan

MOLECULAR REGULATION OF THE Heterothallic strains of Closterium peracerosum- DIATOM CELL CYCLE strigosum-littorale complex are unicellullar charo- Marie JJ Huysman1 ([email protected]), Wim phycean algae, having morphologically indistin- + Vyverman2 ([email protected]) and Lieven guishable two sexes: mating type plus (mt ) and De Veylder1 ([email protected]) mating type minus (mt-). Sexual reproduction is easily induced when cells of these two sexes are 1Department of Plant Systems Biology, VIB-Ghent cultured together in nitrogen-depleted medium in University, Ghent 9052, Belgium and 2Department of the light. Two glycoproteinaceous sex pheromones Biology, Ghent University, Ghent 9000, Belgium (PR-IP and PR-IP Inducer) involved in the progress of sexual reproduction of the C. psl. complex have Accounting for approximately twenty percent of the been well characterized. The PR-IP Inducer induces primary production on Earth, the unicellular eukaryo- the release of PR-IP from mt+ cells, whereas PR-IP tic group of diatoms plays a key ecological and bio- induces the release of gametic protoplasts from mt- geochemical role in our contemporary oceans. cells, during the sexual reproduction. Through the Furthermore, diatoms produce various pigments and microarray analyses, we identified a gene encoding lipids, and are characterised by their finely ornamen- a novel receptor-like protein kinase and named ted silica cell wall, and therefore they hold great CpRLK1. The CpRLK1 gene encodes an 1159-aa promise for different industrial fields, including protein containing an extracellular domain, a Keynote and Oral Papers 68 transmembrane domain, and a kinase domain. The amount of theoretical work on PAR genetics and evo- CpRLK1 protein was produced after the mixing of lution, these genomic regions have remained poorly both mating-type cells and was also detected only characterized empirically, even in classic model in mt+ cells in the presence of PR-IP Inducer. In organisms. We show that although the PARs of the addition, confocal laser microscopy using CpRLK1- U/V sex chromosomes of Ectocarpus recombine at a specific antibody revealed that CpRLK1 proteins similar rate to autosomal regions of the genome, they were localized on the conjugation papilla exclu- exhibit many features typical of non-recombining sively from one of the paired cells. Analyses of regions. The pseudoautosomal regions also preferen- phylogenetic relationships and of extracellular tially accumulate sporophyte-biased genes, which domain organization suggested that CpRLK1 was tend to occur in physically linked clusters. A model- a member of the CrRLK1L-1 subfamily, which acts ling-based approach was used to investigate possible as a cell wall integrity sensor in higher plants. Mt+ evolutionary mechanisms underlying this enrichment cells with knockdown of CpRLK1 showed reduced in sporophyte-biased genes. We provide the first competence for sexual reproduction and formed an detailed analysis of the recombining regions of a hap- abnormally enlarged conjugation papilla after pair- loid sex chromosome system and propose a mechan- ing with mt- cells. The knockdown cells were ism that may explain some of the exceptional unable to release a protoplast, which is indispensa- evolutionary features of these regions compared with ble for zygote formation. We suggest that the autosomes. CpRLK1 protein is an ancient cell wall sensor that now functions to regulate osmotic pressure in the cell to allow proper protoplast release. 7OR.11 CONSERVATION OF THE AUTOPHAGY PATHWAY IN PHYTOPLANKTON AND ITS 7OR.10 ROLE DURING PHOSPHOROUS STRESS UNUSUAL FEATURES OF THE Adva Shemi ([email protected]) PSEUDOAUTOSOMAL REGION OF A U/V PAIR OF SEX CHROMOSOMES Department of plant & environmental sciences, Aga P Lipinska1 ([email protected]), Remy Weizmann Institute of Science, Rehovot 7610001, Luthringer1 ([email protected]), Denis Israel Roze2 ([email protected]), Alexandre Cormier1 ([email protected]), Akira F Peters3 (akira. Phytoplankton contributes ~50% of the global photo- [email protected]), J Mark Cock4 (cock@sb-roscoff. synthesis and serve as the foundation of marine food fr) and Susana M Coelho1 ([email protected]) webs. Although their eco-physiology is extensively studied, some basic aspects of the algal cell biology remain 1Integrative Biology of Marine Models, Roscoff obscure. The recent wealth of algal genomic resources 29680, France; 2Evolutionary Biology and Ecology of has opened new frontiers to decipher cellular pathways Algae, Roscoff 29680, France; 3Behzin Rosko, Santec and their ecological function. Autophagy is a common 2980, France eukaryotic pathway to recycle unwanted cytoplasmic content via specialized vesicles, serving as a key cellular The genetic determination of sex requires either non- mechanism against pathogens and nutrient starvation. recombining chromosome regions or complete sex We performed a genomic analysis of autophagy-related chromosomes, both of which have evolved indepen- (ATG) proteins in green, red and chromalveolate algae. dently and repeatedly across different eukaryotic spe- We elucidate that ATG proteins are conserved among cies. While the processes shaping the evolution of sex green algae, but intriguingly missing in red algal gen- chromosomes are increasingly well understood in omes, suggesting that autophagy is not conserved in red diploid organisms, haploid sex determination systems algae as it is in the entire eukaryote domain. However, (U/V) have been under-studied. We have recently chromalveolates retain ATG genes, despite being sequenced and analysed the sex determining region derived from the red plastid lineage, raising fundamental of the brown alga Ectocarpus, where sex is expressed questions regarding the acquisition of ATG genes during in the gametophyte generation, during the haploid algal evolution. Among chromalveolates, Emiliania phase of the life cycle, and both the female (U) and huxleyi (Haptophyta), a bloom-forming coccolitho- the male (V) sex chromosomes contain sex-determin- phore, possesses a complete set of ATG genes. In light ing regions (SDRs; Ahmed et al. 2014, Current of this, the role of autophagy in E. huxleyi cells was Biology). Here, we use experimental and theoretical addressed during phosphorous (P) limitation, typical for approaches to investigate the extensive pseudoauto- many aquatic ecosystems. E. huxleyi exhibits remark- somal regions (PARs) that border the SDR on the able physiological abilities during P scarcity, including Ectocarpus sex chromosome. Despite a considerable internal P storage, induction of phosphatases and Keynote and Oral Papers 69 transporters. We investigated additional cellular Institute of General Botany, Friedrich Schiller mechanisms that may promote survival of P deficient University Jena, Jena 07743, Germany cells. Upon P-limitation, ATG gene expression was induced, together with formation, acidification and Cryptochromes (CRYs) are a class of blue-light degradation of autophagic vesicles. Moreover, the mem- sensitive flavoproteins found in plants, fungi, brane’s lipid composition was remodeled, as ~30% of microbes and animals. In the green alga the phospholipids were substituted with sulfo- and Chlamydomonas reinhardtii, a plant CRY and an betaine lipids during acclimation to P limitation. animal-like CRY (aCRY) exist. Interestingly, Interestingly, the autophagy inhibitor wortmannin aCRY acts not only as a blue light-, but also as a reduced phospholipid substitution, proposing a possible yellow and red light-sensory receptor [Beel et al., interplay between the two processes. These bioinfor- Plant Cell, 2012 (24): 2992-3008; Spexard et al., matic analyses and lab-based experimental findings pro- Biochemistry, 2014 (53): 1041-1050]. In C. rein- vide basis for future field experiments regarding the role hardtii, two steps in its sexual life cycle are con- of autophagy in natural populations in the ocean. trolled by light, gametogenesis and zygote germination [Huang and Beck, PNAS, 2003 (100): 6269-6274]. It was shown that gametogenesis depends largely on blue light but also to a small 7OR.12 extent on red light [Weissig and Beck, Plant THE ROLE OF AN ANIMAL-LIKE Physiology, 1991 (97): 118-121]. Phototropin was CRYPTOCHROME IN THE LIFE CYCLE OF shown to be involved in this process but it is not THE UNICELLULAR GREEN ALGA able to perceive red light. Since aCRY is the only CHLAMYDOMONAS REINHARDTII so far known photoreceptor that can absorb red light in C. reinhardtii, we started to examine if it Yong Zou ([email protected]), Nico Müller plays a role in the life cycle of C. reinhardtii. Here, ([email protected]) and Maria Mittag we will present data about changing expression ([email protected]) levels of aCRY and its role during the life cycle. Keynote and Oral Papers 70

8. Algal biodiversity and ecosystem function: new scenarios in coastal systems

8KN.1 Biology and Geology Department, University Rey Juan Carlos, Móstoles 28933, Spain THE CONSEQUENCES OF CHANGES IN ALGAL BIODIVERSITY The loss of canopy-forming algae, such as fucoids and Lars Gamfeldt ([email protected]) kelps, has been documented across many parts of the world, and has often been attributed to climate change Department of biological and environmental sciences, and other human related stress factors. A major chal- University of Gothenburg, Gothenburg SE-40530, lenge in ecology is not just to understand and predict Sweden changes in the distribution of key species under climate change, but also to identify the impacts of these changes The Earth’s environment is rapidly changing, on the ecosystem functioning. The rocky coasts of mainly due to a growing human population and Iberian Peninsula constitute the southern range limit more diverse activities. Much research has focused for a considerable number of canopy-forming, cold- on the impact of such environmental changes on temperate algae, which dominate shores of Northern biodiversity. There is now accumulating evidence Europe. Among these species is found the intertidal that the opposite relation will also occur: changes seaweed Fucus serratus. Recent observations have indi- in biodiversity will greatly feed back to the envir- cated a continuous drastic westward retraction of this onment and ecosystem processes. The first experi- species in N Spain, related to ocean warming and other mental manipulations of biodiversity emerged in the climatic factors linked to emersion times. The local early 1990’s, and since then there has been an extinction of F. serratus hasleadtochangesinthe exponential increase in the number of published structure of the benthic assemblages and lower trophic studies. Theory predicts that biodiversity can be an positioning of some consumers, which suggests an over- important factor influencing how ecosystems work, all shrinkage of the food chains length. As a conse- because species occupy distinct niches, can be com- quence of the observed distribution retraction, the plementary in their use of resources, and experience presence of F. serratus in the NW Iberian Peninsula is positive interactions. Indeed, communities with a nowadays virtually limited to a few scattered but persis- diverse set of species generally produce more bio- tent populations, mostly inside large embayments (rías) mass and use resources more efficiently, compared of Galicia. These remnant populations show signs of to average communities with fewer species. local adaptation/acclimation and are located in places This talk will give an overview of the current state- with more benign environmental conditions than sur- of-the-art when it comes to research about the func- rounded areas. Their future viability will depend in part tional consequences of changes in algal biodiversity: on the expected trends of upwelling strength in the area. what we currently know, and where we need to go A recent study reveals a weakening of the Iberian upwel- next. It will provide a range of examples, from both ling during the last decades. The retreat of canopy- experimental and observational studies, in freshwater forming algae seems to be a general phenomenon in and marine systems. the Iberian Peninsula, involving other fucoid and kelp species. Under present and future climatic scenarios, local extinctions of coastal ecosystem engineers would entail a reorganization of natural assemblages and the 8KN.2 simplification of coastal food-webs. STRUCTURE AND DYNAMICS OF THE SOUTHERN RANGE LIMIT OF A CANOPY- FORMING ALGA AND THE CONSEQUENCES 8OR.1 FOR THE COASTAL ECOSYSTEM FUNCTIONING CHANGES IN PHYTOPLANKTON COMMUNITY COMPOSITION AFFECT Rosa M Viejo ([email protected]), Brezo Martínez BIOGEOCHEMICAL FLUXES; AN INDIRECT ([email protected]) and Duarte Linney (linney. EFFECT OF GLOBAL CHANGE [email protected]) Keynote and Oral Papers 71

Kristian Spilling1 (kristian.spilling@environment.fi), Anke Kremp1 (anke.kremp@environment.fi), Riina School of Biological Sciences, University of Essex, Klais2 ([email protected]), Kalle Olli2 (kalle.olli@ut. Colchester CO4 3SQ, United Kingdom ee) and Timo Tamminen1 (timo.tamminen@environ ment.fi) Intertidal microphytobenthos, the community of 1Marine Research Centre, Finnish Environment benthic diatoms and associated other species that Institute, Helsinki 00251, Finland and 2Univ. Tartu, dominate many soft-sediment habitats, often exhibit Tartu 51005, Estonia significant levels of spatial variability in biomass. We show that more than 25 % of microphytobenthos The spring bloom in the Baltic Sea is by far the most variability within Colne Estuary, UK, was due to important phase of the annual succession in terms of differences between the replicates (at spatial scale < primary production. Two phytoplankton groups are 0.5 m). A pronounced relationship was revealed predominant during this period: diatoms and dinofla- between the MPB ‘phase of growth’ (determined gellates. Climatic changes have caused dinoflagellates using chl a and colloidal carbohydrate concentrations) to become more dominant at the expense of diatoms in with species richness, species composition and rela- parts of the Baltic Sea. We investigated the effects of tive abundance. Nonetheless, relative abundance of phytoplankton community composition on spring the most dominant species Gyrosigma balticum and bloom carbon flows and nutrient stoichiometry in common species Gyrosigma scalproides, Gyrosigma multi-year mesocosm experiments. Comparison of dif- limosum, Gyrosigma litorale, Diploneis didyma, fering communities revealed that community structure Pleurosigma angulatum and Navicula digitoradiata significantly affected C accumulation parameters, with can be used to imply the MPB biofilm ’phase of highest particulate organic carbon (POC) build-up and growth’. The dominance of these species in the bio- dissolved organic carbon (DOC) release in diatom- film, however, was reduced by the appearance of dominated communities. In terms of inorganic nutrient centric planktonic species such as Coscinodiscus spp drawdown and bloom accumulation phase, the domi- and Actinoptychus splendens during periods of spring nating groups behaved as functional surrogates. tides. Species richness of lag and early exponential Dominance patterns, however, significantly affected phases, and latter exponential and stationary phases C:N:P:Chl a ratios over the whole bloom event: when were found to range between 28 to 34 species and 36 diatoms were dominant, these ratios increased com- to 45 species, respectively. In addition, ‘older’ bioflm pared to dinoflagellate dominance or mixed commu- ‘phase of growth’ had lower Shannon Wiener species nities. Diatom-dominated communities sequestered diversity than earlier stage biofilm. This study has carbon up to 3.6-fold higher than the expectation proved that MPB assemblages, even in a same biofilm based on the Redfield ratio, and 2-fold higher com- mat (at scale < 0.5 m) can have different a ‘phase of pared to dinoflagellate dominance. Furthermore, after growth’, which strongly depends on the species rela- the peak of the spring bloom diatoms generally settle tive abundance and richness. Also, the age of MPB quickly to the sea floor causing aggravated oxygen biofilm showed to control the erosion effect on the conditions in bottom waters, whereas dinoflagellates MPB community during immersion and the biofilm either lyse already in the water column or produce ‘phase of growth’ in the following emersion period. resistant resting cysts that do not degrade in the sedi- Henceforth, the high variability derived from the dif- ment. The dominance by either phytoplankton group ference between the replicates, which normally thus affects directly both the summertime nutrient known as ‘background noise’ is actually a product of pools of the water column, and the input of organic different age or ‘phase of growth’ of the MPB biofilm. matter to the bottom sediments, to contrasting direc- tions. Our results highlight the need for remote sensing technologies with taxonomical resolution. Climate-dri- 8OR.3 ven changes in phytoplankton dominance patterns will have far-reaching consequences for major biogeo- INFLUENCE OF INTERSPECIFIC chemical cycles and need to be considered in climate COMPETITION ON PHOTOSYNTHETIC change scenarios for marine systems. RATES OF ALGAL COMMUNITIES Jana Wegbrod ([email protected])

8OR.2 Institute of Biochemistry and Biology, University of Potsdam, Potsdam 14469, Germany INFLUENCE OF SEDIMENT BIOFILM ‘ ’ PHASE OF GROWTH ON HIGH Resource competition is a major determinant for the MICROPHYTOBENTHOS (MPB) structure and dynamics of diverse phytoplankton VARIABILITY ON AN INTERTIDAL FLAT communities. Due to taxon specific functional traits Nurul Shahida Redzuan ([email protected]) of primary producers, species richness in diverse Keynote and Oral Papers 72 communities might be the underlying mechanism characteristic in driving both algal species richness mediating biodiversity effects. For the purpose of and individual species abundance. Prior to analysis, light harvesting, species rich phytoplankton commu- the species Corallina officinialis, was of particular nities are able to use the different spectral components interest because it provides hard, complex structure of the photosynthetic active radiation (PAR) more within the algal community, possibly promoting addi- effectively, related to differences in composition tional algal settlement. We found that aspects of both with accessory pigments and light acclimation. We the micro- (i.e., slope and depth) and macro-habitat conducted measurements using the Pulse Amplitude (i.e., elevation and grazer abundance) of these pools Modulation fluorometry (PAM) based on differences drive species richness, with effects for each covariate in accessory pigments among phytoplankton taxo- ranging in both sign and strength. Corallina abun- nomic groups as well as fluorescence based chloro- dance appears to be only weakly influenced by a phyll a quantification to assess the influence of subset of these variables, but its abundance is posi- competitive stress on the photosynthetic performance tively related to overall species richness. Thus, key of selected phytoplankton species. In growth experi- individuals may contribute to overall patterns of diver- ments under competitive co-limitation for phosphorus sity. These results suggest that habitat characteristics, and light we compared the photosynthetic capacity of which become biologically relevant at different levels mixed algae communities, either i) grown together of observation, may differentially influence individual experiencing interspecific competition or ii) pipetted species within the community in addition to species artificial communities out of monocultures experien- richness as a whole. Therefore, the scales at which cing intraspecific competitive stress. We assume that these characteristics affect the establishment and sur- the intra- and interspecific competitive ability of phy- vival of various species will collectively dictate the toplankton species for light does affect the photosyn- patterns observed in species richness across a hetero- thetic rates of phytoplankton species. We argue that geneous habitat. the light availability and nutrient supply ratio to each phytoplankton cell is directly affected by the competing cells in close vicinity. First results and interpreta- 8OR.5 tions respecting the effects of interspecific competition on the photosynthetic capacity on algal UNCONSCIOUS UNCOUPLING: LIFE CYCLE communities will be presented. PLASTICITY FACILITATES MACROALGAL INVASIONS Stacy A Krueger-Hadfield1 ([email protected]), 8OR.4 Nicole Kollars2 ([email protected]), Allan E Strand1 ([email protected]), James E Byers3 (jebyer HABITAT CHARACTERISTICS DRIVING 4 [email protected]), Thomas Greig (thomas.greig@noaa. SPECIES RICHNESS IN ROCK POOLS 5 gov), Mareike Hammann (mareike_hammann@web. Rebecca L Atkins ([email protected]) de), David Murray6 ([email protected]), Sarah Shainker7 ([email protected]), Ryuta Terada8 Ecology, University of Georgia, Tallahassee 32312, (terada@fish.kagoshima-u.ac.jp), Florian United States Weinberger5 (Florian Weinberger) and Erik E Sotka1 ([email protected]) Species richness is a key aspect of community structure, and can influence the stability and magnitude of 1Grice Marine Laboratory, College of Charleston, ecosystem functions. Often, patterns of species rich- Charleston 29412, United States; 2Grice Marine ness are attributed to heterogeneity (i.e., variation in Laboratory, College of Charleston, Charleston physical and biotic factors) across habitat. However, 29412, United States; 3Odum School of Ecology, describing this heterogeneity-richness relationship University of Georgia, Athens 30602, United States; requires an initial understanding of how species 4NOAA National Ocean Service, Center for Coastal simultaneously respond to a multitude of habitat char- Environmental Health and Biomolecular Research, acteristics generated at different spatial scales (e.g. Charleston 29412, United States; 5Helmholtz- micro- vs. macro-habitat). Using intertidal rock Zentrum für Ozeanforschung Kiel (GEOMAR), Kiel pools as a model system, we systematically surveyed D-24105, Germany; 6Grice Marine Laboratory, multiple quadrats within individual pools to differenti- Charleston 29412, United States; 7Biology, College of ate between micro-habitat characteristics which vary Charleston, Charleston 29424, United States and within the pool (i.e., surface complexity, depth, slope), 8Fisheries, Kagoshima University, Kagoshima City and macro-habitat characteristics which pertain to the 890-0056, Japan entire pool (i.e., elevation, volume, grazer abundance). We then applied mixed effects models to Macroalgae comprise nearly 20% of all marine species quantify the relative importance of each habitat introduced into non-native habitats and profoundly Keynote and Oral Papers 73 alter local detrital and trophic food webs. We propose integrated into a spatio-temporal model of a coastal that the success of macroalgal invaders depends on the environment in order to make predictions about the flexibility of its biphasic life cycle to respond to local potential growth dynamics under different environ- environments. Using 10 microsatellite loci to genotype mental conditions. Comparisons between model pre- > 2000 individual thalli from across 62 populations, we dictions and field studies of an invasive population of found that the haploid-diploid red alga Gracilaria ver- U. pinnatifida in Brest harbour, France, show good miculophylla expanded from northern Japan and quantitative agreement in terms of relative abun- entered high-salinity, temperate estuaries across three dances, rates of recruitment and life expectancies of continental margins of the Northern Hemisphere. In its mature sporophytes. Future work will include using native range, G. vermiculophylla is mostly found on the model to make predictions about their potential intertidal hard substrata and ~60% of individuals are responses to changing climatic conditions and to diploid. In contrast, most G. vermiculophylla popula- assess the risk for future range expansion in tions in non-native habitats are found on soft-sedi- European coastal waters. ments, occurring as drifting mats or anchored by Diopatra worms. Accompanying this ecological shift is an uncoupling of the biphasic life cycle in the non- 8OR.7 native range. Twenty-four of 35 non-native populations exhibited diploid frequencies of 90%. Eleven of these THE INTEGRAL ROLE OF PHAEOPHYCEAE 24 populations were at diploid fixation. The ecological TO DRIVE COASTAL IODINE FLUXES: CASE and evolutionary consequences of the functional loss of STUDIES FROM IRELAND free-living stages are poorly understood, as are the Udo Nitschke ([email protected]) and mechanisms underlying the evolution and maintenance Dagmar B Stengel ([email protected]) of biphasic life cycles. Yet, this life-cycle flexibility likely facilitates invasion success of biphasic groups, Botany and Plant Science, School of Natural such as macroalgae and, thereby, represents an impor- Sciences, and Ryan Institute, National University of tant, but poorly described component of global change. Ireland Galway, Galway N/A, Ireland

Biogeochemical processes of iodine in coastal marine 8OR.6 systems are largely driven by brown macroalgae. Through exposure to environmental stressors many MODELLING THE POPULATION DYNAMICS iodine-rich Phaeophyceae can act as biological source UNDARIA PINNATIFIDA OF INVASIVE USING of iodine, influencing not only hydrological and atmo- AN INDIVIDUAL-BASED APPROACH spheric chemical processes but also human health. James Murphy1 ([email protected]), Mark However, the capacity of Phaeophyceae to retain and Johnson2 ([email protected]) and release iodine remains to be quantified. We have Frédérique Viard1 ([email protected]) developed a cost-effective HPLC method to measure total iodine contents in macroalgal matrices and inves- 1Lab. Adaptation & Diversity in Marine Environment, tigated the release of algal iodine in relation to the Station Biologique de Roscoff, Roscoff 29680, France physiological state. Laminariales collected from the and 2Ryan Institute, NUI Galway, Galway n/a, Ireland Irish west coast contained iodine at levels up to two orders of magnitude higher than Fucales, although In this project, an individual-based modelling considerable intra-thallus and seasonal variation was approach (in association with field studies, ecological observed; this suggests an environmental impact on experiments and molecular work by the research algal iodine metabolism. Laminaria digitata emitted group) is being taken to study the impact of an impor- large quantities of iodine into the atmosphere imme- tant invasive kelp species, Undaria pinnatifida,on diately following air-exposure; iodine emission rates native biodiversity in European coastal waters under were enhanced under abiotic stress conditions and variable climatic conditions. The theory of autono- appeared to depend on tissue iodine concentration. mous agents is a useful approach for the modelling Under submersion, low salinities caused a decrease of algae communities as it allows large-scale popula- in the physiological performance which coincided tion models to be derived from simple rules dictating with increased iodine release into seawater, indicating the growth and interactions of the individual mem- an osmotic function of iodine. During degradation, bers. A detailed model of the life history of U. pinna- algal biomass released and emitted large quantities tifida (including both the microscopic and of iodine into the environment, demonstrating that macroscopic stages of its life cycle) has been devel- the biogenic iodine transfer in coastal marine systems oped using empirical data from the literature on their is further driven by degrading biomass. Our results responses to various enviornmental factors (e.g. light, emphasise the integral role of temperate water temperature, day length). This has been Phaeophyceae in the coastal iodine cycle. We provide Keynote and Oral Papers 74 evidence that physiological responses and degrading weeds and microalgae) to their immediate environ- biomass of brown macroalgae are the main vectors of ment (including climate change, harvesting coastal iodine fluxes. regimes, water quality) is thus fundamental to the future development of algal biotechnology. However, the application of ecological knowledge 8OR.8 needs to reach beyond provision of baseline data to industry. With increasing commercial pressures, BRIDGING THE GAP BETWEEN ALGAL the sustainable supply of algal biomass for specific ECOLOGY AND BIOTECHNOLOGY – MORE applications, which can potentially be sourced THAN JUST LEARNING A NEW LANGUAGE from natural or cultivated stocks, becomes critical. Dagmar B Stengel ([email protected]) This presentation gives an overview of current research aimed at identifying the drivers of Botany and Plant Science, School of Natural Sciences observed variability and the application of physio- and Ryan Institute, National University of Ireland logical mechanisms to enhance bioactivity in nat- Galway, Galway Gal1, Ireland ural algal biomass (through selective harvesting, or via targeted, optimised biomass production in cul- The assessment of algal chemical composition has ture) for safe and stable algal products from sus- become an important integral component of tainable sources. Despite technical advances in the numerous international research programmes that development of analytical methods, the biological investigate new sources of high-value compounds. pathways that implicate commercial value of algal Of particular interest to food, agricultural, pharma- biomass are still poorly characterised even for the ceutical and cosmetics industries are commercially most commonly used algal species; also there are valuable metabolites such as phycobilines, carote- significant gaps in our understanding of chemical noids, MAAs, fatty acids and phenolic compounds. diversity and the variability of algal bioactives, Fulfilling multiple physiological functions, clearly and the natural and process-induced factors that some compounds vary naturally according to algal control them. Additionally, dialogue with industry species under investigation, location and season, is essential to identify specific research needs amongst many other factors. Understanding the while ensuring sustainable management of natural ecological and metabolic responses of algae (sea- resources and preserving ecosystem integrity. Keynote and Oral Papers 75

9. Algae in stressful environments

9KN.1 At high latitudes, algae encounter extreme light con- EXTENSIVE GENETIC DIVERSITY AND ditions, ranging from months-long darkness during DIFFERENTIAL BI-ALLELIC EXPRESSION the Polar night, to sudden high-light exposure during IN A SOUTHERN OCEAN DIATOM ice break-up in spring/ summer, when the sun never Thomas Mock ([email protected]) sets. At present, very little is known about how microalgae overwinter at latitudes where the sun does not School of Environmental Sciences, University of East rise for several months. In addition to resting stages in Anglia, Norwich NR4 7TJ, United Kingdom the sea ice or sediment, vegetative cells of numerous species occur in the water column throughout the Despite being one of the most inhospitable regions on entire winter (although in extremely low abundances). Earth, the Southern Ocean houses a highly diverse and A recent attempt to describe their physiological state productive community of organisms. Unicellular eukar- revealed a system that, even in the middle of the Polar yotic diatoms are the main primary producers in this night, has the potential to resume photosynthetic pro- environment where photosynthesis is limited by low duction, virtually instantaneously, upon re-illumina- concentrations of dissolved iron, large annual fluctua- tion. Furthermore, resting stages from sediment tions in light, temperature and the extent of sea ice. How surfaces reacted to light exposure after only 6 days – diatoms have evolved to this extreme environment is their activity levels, growth rate and primary produc- largely unknown. Here we present insights into the tivity being dependent on both day length and light evolution of a cold-adapted (psychrophilic) diatom intensity. Since algae from sediment, sea ice and sea- from the Southern Ocean, Fragilariopsis cylindrus. water habitats likely contribute to the seeding popula- Our study reveals that the genome of F. cy li nd rus con- tion responsible for the very distinct spring peak in tains highly diverged alleles that are differentially annual productivity after the winter, a comprehensive expressed depending on the environmental conditions understanding of physiological adaptations is very and stresses imposed. Alleles with largest ratio of repla- important. The bulk of primary production in the cement over silent substitutions (largest dN/dS ratio) high Arctic occurs during this relatively short transi- show the most pronounced condition-dependent expres- tion from spring to early summer. As soon as sufficient sion. This suggests that environmentally-induced diver- light becomes available, extremely shade-adapted sifying selection drives the allelic differentiation. The algae in the bottom layer of sea ice start forming highly diverged alleles with nucleotide divergence of up blooms, usually well before their pelagic counterparts to 6% show nevertheless a signature of genetic recom- build up high biomass. However, during the ice-melt- bination. Many of the differentiated alleles encode pro- ing period, optical conditions in the sea ice environ- teins from conserved core and lineage-specific ment undergo abrupt changes, ending with surface metabolism indicating the requirement to fundamentally blooms in open water that are exposed to very high adjust metabolism to cope with an extreme and variable irradiances. Such alterations in light conditions have a environment. These homologs account for 73% of all F. pronounced effect on algal physiology and biochem- cylindrus-specific transcripts in natural sea-ice commu- ical composition, including elemental stoichiometry nities, including the most highly abundant transcripts. In or essential polyunsaturated fatty acids. this vast gene pool, allelic variants adapted to particular conditions are maintained, thereby enabling the population to respond to the highly variable environment of the 9OR.1 surface Southern Ocean. BIODIVERSITY ASSESSMENT AND TRANSCRIPTOMIC ANALYZES OF 9KN.2 EUKARYOTIC SEA ICE DIATOMS OF THE FROM ETERNAL DARK TO HIGH LIGHT CENTRAL ARCTIC OCEAN STRESS: MICROALGAE IN THE HIGH Anique Stecher1 ([email protected]), Anique ARCTIC AND THE CHALLENGE OF 2 2 Stecher ([email protected]), Madlen Franze DIFFERENT EXTREMES 3 ([email protected]), Marco Groth (mgroth Eva Leu ([email protected]) @fli-leibniz.de), Lars Harms4 ([email protected]), Arctic R&D, Akvaplan-niva, Tromsø 9296, Norway Gernot Glöckner5 ([email protected]), Keynote and Oral Papers 76

Gernot Glöckner6 ([email protected]), Graham JC Underwood ([email protected]) and Sandra Heinrich7 ([email protected]), Peter G Shazia N Aslam ([email protected]) Kroth1 ([email protected]) and Klaus Valentin2 ([email protected]) Biological Sciences, University of Essex, Colchester CO4 3SQ, United Kingdom 1Department of Biology, University of Konstanz, Konstanz 78464, Germany; 2Polar Biological Abundant and productive assemblages of predomi- Oceanography, Alfred Wegener Institute Helmholtz nantly pennate diatoms are found living in the net- Center for Polar and Marine Research, Bremerhaven works of brine channels and pores within sea ice. 27570, Germany; 3Leibniz Institute for Age Research, These algae are exposed to steep gradients in condi- Fritz Lipmann Institute, Jena 07745, Germany; tions across the vertical profile of ice flows, experien- 4Scientific Computing, Alfred Wegener Institute cing temperatures as low as minus 20°C and salinity Helmholtz Center for Polar and Marine Research, values in excess of 50. One adaptation to these stress Bremerhaven 27570, Germany; 5Ecosystem conditions is enhanced production of a range of extra- Research, Leibniz Institute of Freshwater and Inland cellular polymeric substances (EPS, mucilages) that Fisheries, Berlin 12587, Germany; 6Institute for appear to provide a protective function to the cells. Biochemistry I, University of Cologne, Cologne Results from culture studies on the diatoms 50931, Germany and 7Functional Ecology, Alfred Cylindrotheca closterium, and the ice diatoms Wegener Institute Helmholtz Center for Polar and Fragilariopsis cylindrus, F. curta and Synedropsis Marine Research, Bremerhaven 27570, Germany sp., reveal that EPS can protect cell growth and photosynthesis from chronic and acute salinity stress, and Sea ice is a large environment controlled by a number of that EPS production is altered under a matrix of chan- hostile abiotic factors, i.e. low temperatures, low light ging conditions of temperature and salinity similar to intensities, and high salinities. Despite these harsh con- those experienced in the sea ice environment. These ditions, it is inhabited by a diverse community and laboratory data are compatible with field observations significantlycontributingtoprimaryproductioninice- on EPS concentrations and composition from Arctic covered regions. While this biodiversity has been inves- and Antarctic sea ice cores, which reveal the existence tigated by classical methods in the past, little is known of consistent patterns in the characteristics of EPS. Sea about its functional biodiversity, i.e. which species are ice diatoms are the major producers of EPS in sea ice, actively contributing with which functions to the com- and these EPS play an additional role in water column munity. By sequencing 18S rRNA and rDNA ampli- processes after seasonal ice melt. EPS have also been cons, we found an over-representation of certain groups implicated in ocean-atmosphere interactions. Thus the (i.e. Bacillariophyceae and Ciliophora) in the active part physiological responses of diatoms to the stresses of of the community. Furthermore, we were able to isolate living within the sea ice matrix are connected to larger an abundant naviculoid sea ice diatom member of the scale environmental processes. Arctic sea ice community (CCMP2297) and conducted temperature stress experiments (10 °C, 5 °C, -2 °C, -5 ° C) to analyze physiological and transcriptional acclimation to high and cold temperature stress. Differential 9OR.3 gene expression was investigated using RNASeq wih a VEGETATIVE SURVIVAL AND STRESS HiSeq2500 sequencer. We observed that based on phy- TOLERANCE OF ZYGNEMA SPP. siological parameters this diatom has a broad thermal (ZYGNEMATOPHYCEAE, STREPTOPHYTA) range (5 °C to -5 °C). Remarkably, stress levels that did IN POLAR REGIONS not lead to physiological alterations already caused a transcriptomic response. The highest number of differ- Martina Pichrtová1 ([email protected]), Tomáš ential expressed transcripts was found in response to 5 ° Hájek2 ([email protected]), Josef Elster3 (jel C, indicating that this temperature is more harmful to [email protected]) and Andreas Holzinger4 CCMP2297 than low temperatures. ([email protected])

1Department of Botany, Charles University in Prague, 9OR.2 Faculty of Science, Prague 12801, Czech Republic; 2Instute of Botany, The Czech Academy of Sciences, ADAPTATION OF DIATOM Trebon 37982, Czech Republic; 3Centre for polar EXTRACELLULAR POLYMERIC SUBSTANCE ecology, University of South Bohemia, Faculty of (EPS) PRODUCTION IN RESPONSE TO Science, Ceske Budejovice 37005, Czech Republic TEMPERATURE AND SALINITY STRESS IN and 4Institute of Botany, University of Innsbruck, SEA ICE ENVIRONMENTS Innsbruck 6020, Austria Keynote and Oral Papers 77

Filamentous conjugating green algae (Zygnemato- these areas, their occurrence in a region can vary phyceae) belong to the most common primary produ- greatly. Many attempts have been made to decipher cers in the polar hydro-terrestrial environment. In such the decisive abiotic and biotic factors - often with a unstable habitats, organisms are subject to various focus on a small set of specific factors. In August 2013 stress factors, e.g., freeze–thaw cycles, desiccation we performed a field campaign in the Svalbard archi- and high irradiation levels. Polar Zygnema spp. were pelago, surrounding the Island of Spitsbergen and examined under various stress conditions both in the parts of Nordaustlandet. Large scale mapping of red, field and in experiments with cultures. At the end of green (and white) snow, microscopic and chemical summer, the cells gradually lose their typical appear- analyses of field samples, examination of the respec- ance (with large vacuoles and stellate chloroplasts) tive geology, digital mapping of snow and glacier field and form pre-akinetes, stationary-phase-like cells. topography and structure using an unmanned air vehi- Such modified vegetative cells are filled with lipids cle (UAV) with visible and thermal infra-red cameras, and characterized by reduced chloroplast lobes and together with field observations from earlier expedi- thickened cell walls. Formation of pre-akinetes in field tions and considerations of the climatic conditions led conditions was not triggered by desiccation, but hard- to a rather rough, but conclusive explanation of the ening during slow dehydration was required for the distribution patterns of snow algae on Svalbard. No pre-akinetes to become osmotic stress tolerant. In single chemical factor (pH, nutrients), nor field topo- experimental conditions the formation of pre-akinetes graphy and the relating water availability, nor the was induced by nitrogen starvation. In general, viabi- underlying geological formation was a sole decisive lity and recovery rate after experimental desiccation factor promoting snow algae. On a small scale such depended on pre-cultivation conditions and drying measurements might explain local snow algal com- rate. The pre-akinetes survived even rapid drying (at munities, but from a more comprehensive view, one 10% relative air humidity) when hardened by mild factor such as the main geology, e.g. of carbonate dehydration stress and viable pre-akinetes were even rocks prevailing in a region or the overall extremely observed in field conditions during winter. The results dry climatic conditions in a cold desert can dominate indicate that naturally hardened pre-akinetes play a negatively over other, rather beneficial factors. This key role in survival under extreme conditions of presentation will present data from the field cam- polar climate, while the production of specialized paigns and will try to convey this rather integrative cells with resistant cell wall (e.g., zygospores) is lar- approach to explain the occurrence of these very inter- gely suppressed. Moreover, desiccation-tolerant cells esting extremophiles. derived from disintegrated filaments can act as air- borne propagules. 9OR.5 CYANOBACTERIA AND MICROBIAL MATS 9OR.4 IN ANTARCTIC TERRESTRIAL AQUATIC SNOW ALGAE ALL OVER SVALBARD? - AN ECOSYSTEMS: DIVERSITY, DISTRIBUTION (OTHER) ATTEMPT TO EXPLAIN THEIR AND RESPONSE TO ENVIRONMENTAL DISTRIBUTION PATTERNS VARIABLES Thomas Leya1 ([email protected]), Anne D Jungblut1 ([email protected]), Megan Jens Klump2 ([email protected]) and Guenter Krusor2 ([email protected]), Tyler Mackey3 Fuhr 3 ([email protected]) ([email protected]), Dawn Sumner4 (dysum [email protected]) and Ian Hawes5 (ian.hawes@can 1Extremophile Research & Biobank CCCryo, terbury.ac.nz) Fraunhofer Institute for Cell Therapy and Immunology, Branch Bioanalytics and Bioprocesses 1Life Sciences, Natural History Museum, London SW7 (IZI-BB), Potsdam 14476, Germany; 2Australian 5BD, United Kingdom; 2Department of Earth and Resources Research Centre (ARRC), Commonwealth Planetary Sciences, University of California, Davis, Scientific and Industrial Research Organisation Davis 95616, United States; 3Department of Earth (CSIRO), Kensington WA 6151, Australia and and Planetary Sciences, University of California, 3Fraunhofer Institute for Biomedical Engineering Davis, Davis 95616, United States; 4Department of (IBMT), St. Ingbert 66386, Germany Earth and Planetary Sciences, University of California, Davis, Davis 95616, United Kingdom and Microscopic algae also thrive on the stressful cold 5Gateway Antarctica, University of Canterbury, environments of snow and glacier fields in high Christchurch 95616, New Zealand polar and many high mountain regions of our earth and their blooms become visible as the phenomenon Antarctic terrestrial aquatic ecosystems in the of red and green snow. Though generally abundant in McMurdo Dry Valleys, Southern Victorialand and Keynote and Oral Papers 78

Ross Island are extreme environments because of Egypt; 3Department of Botany, University of South permanently low temperatures, short growth periods Bohemia, Ceske Budejovice CZ-370 05, Czech and water chemistries. Cyanobacteria are key primary Republic; 4Department of Physics, Bioorganic producers in benthic environments of streams, melt- Chemistry Laboratory, University of Trento, Trento water ponds and perennially ice-covered lakes, and a I-38123, Italy; 5Department of Biology, Toho major structuring agent of microbial mats. Recent University, Funabashi, Chiba 274-8510, Japan and findings have shown the sensitivity of these inland 6Department of Biology and Environmental Science, ecosystems to climatic-driven environmental change, University of New Haven, West Haven CT 06511, and a better understanding of the distribution and United States response of cyanobacteria and other microbes within cyanobacteria-based microbial mats to environmental Starting as an informal collaboration, the scientific stress, will assist in evaluating the resistance and resi- work on the benthic algae of springs and wells of lience of Antarctic freshwater benthic biology to Egyptian Oases has been included in the MUSE change. (Trento, Italy) research programs as the PhyBiO We evaluated cyanobacterial diversity and micro- Project (Phycological Biodiversity in Oases, and the bial mat communities in perennially-ice covered mer- Challenges for its use in Bioassessment of Water omictic lakes in the McMurdo Dry Valleys, Antarctica Resources). This contribution offers an overview on using 16S rRNA gene environmental surveys. These several phycological investigations carried out to lakes are useful models to study the relationship achieve a deeper knowledge of the algal and cyano- between microbial communities and environmental bacterial biodiversity of Egyptian desert springs and variables because they have rich benthic cyanobacter- wells. Analyses are based on barcoding and molecular ial mat accumulations and stable stratification of phy- phylogenetic inference, morphotaxonomy, life cycle sical and chemical conditions. Our analysis suggested features, bioorganic screening, and in some cases that macroscopic morphologies and internal stratifica- cytological observations and karyological analysis. tions of cyanobacteria-based microbial mats differed The following taxa are being addressed: - two species between lakes, and can co-vary with oxygen and light in the green algal genus Rhizoclonium including an levels, and potentially also be influenced by cyano- Egyptian species new to science, R. aegyptiacum bacteria taxa composition. However, the majority of Saber et Cantonati sp. nov., and R. hieroglyphicum cyanobacteria ribotype diversity was shared between collected in Italy; - a Stigeoclonium-like green alga lakes, and only a weak relationship between commu- that is most likely a Caespitella species new to science nity structure and environmental variables such as (from Ain Helwan); - taxa from the green algal genera conductivity and photosynthetically active radiation Zygnema and Zygnemopsis; - stoneworts: Chara vul- and dissolved reactive phosphorus was evident. This garis from two locations in eastern (Moses Springs, suggest that cyanobacteria have the capability to colo- Sinai) and western (Siwa Oasis) Egypt respectively; - nise, adapat and grow across broad environmental Westiellopsis prolifica (cyanobacterium); the red algae ranges, and such adaptability may provide a high Compsopogon (Egypt, thermal spring)/Lemanea degree of community resistance and resilience to (Italy, high-elevation glacial stream), which will future climate-driven-environmental change in include a comparison between the membrane lipids Antarctic terrestrial aquatic ecosystems. of two red algae species with a similar thallus architecture but from thermally contrasting habitats; - diatoms: preliminary analyses already pointed out 9OR.6 species of particular interest in the genera Achanthidium, Halamphora, Navicula, and Ulnaria. BENTHIC ALGAE AND CYANOBACTERIA The environments studied are selective (mineraliza- FROM EGYPTIAN DESERT SPRINGS AND tion, temperature etc.), isolated and thus potentially WELLS: ISOLATED, STRESSFUL, AND highly-interesting from the biogeographic point of IMPACTED FRESHWATER HABITATS view but also strongly-impacted due to exploitation Marco Cantonati1 ([email protected]), by humans because these are the only water resources Abdullah A Saber2 ([email protected]. available in the area. eg), Jan Mareš3 ([email protected]), Graziano Guella4 ([email protected]), Kensuke Ichihara5 ([email protected]), Amy L 9OR.7 Carlile6 ([email protected]) and Andrea Anesi4 LIGHT AND NUTRIENT EFFECTS ON ([email protected]) KETOCAROTENOID SYNTHESIS IN CHODATODESMUS AUSTRALIS 1Limnology and Phycology Research Unit, Museo delle Scienze - MUSE, Trento I-38123, Italy; 2Botany Diana Simionato ([email protected]), Anna Department, Ain Shams University, Cairo 11566, Segalla ([email protected]), Tomas Morosinotto Keynote and Oral Papers 79

([email protected]) and Nicoletta La thus a platform for primary succession and ecosystem Rocca ([email protected]) development studies. Soil algae and cyanobacteria are usually first photoautrotrophic organisms colonizing Biology Department, Padova University, Padova newly exposed terrain where they have to cope with 35131, Italy extreme environmental conditions. To understand the role of particular groups/species of soil algae and During a scientific expedition in Antarctica, in the aus- cyanobacteria as well as main factors affecting devel- tral summer 1990, Prof. C. Andreoli collected a coccoid opment of microalgal communities during succession microalga from a transitory pond near the Gondwana we selected forelands differing in climatic conditions, Station, Terra Nova Bay, Victoria Land (Antarctica). bedrock, altitude, slope, exposure, etc. The study was This organism was recently characterized by a polypha- performed in foreland of 5 glaciers- Storglaciaren sic approach and resulted to be a new species of (Tarfala, Sweden), Hardangerjokulen-Midtdalsbreen Chlorophycea, named Chodatodesmus australis and snout (Finse, Norway) and 3 glaciers in Petuniabukta belonging to the new genus Chodatodesmus (family (Svalbard) - along chronosequences established from Scenedesmaceae) (Sciuto et al., submitted). recently deglaciated sites (early successional stage) at Physiological analysis showed the ability of this the glacier front to old successional stage developed Antarctic isolate to grow at different temperatures since the end of LIA (climax). Soil samples were (from 4°C to 25°C), with an optimum growth rate at collected aseptically from surface layers. Species about 20°C. Chodatodesmus resulted always able to composition, dominant species/groups and abundance synthesize antioxidant carotenoids as part of a photo- of algae were studied by using direct epifluorescence protective mechanism activated to avoid the risk of microscopy and cultivation methods; molecular meth- photoxidative damage by excess of light. In the present ods were applied for identification of problematic study, we tested the effects of different light regimes and species. Similar successional trend in algal commu- nitrogen availability on biomass and carotenoid produc- nity development was observed in all studied fore- tion in C. australis. For this purpose, we exploited a lands. Six to 14 algal species were isolated already small photobioreactor (multicultivator MC1000, Photon in the youngest, completely barren successional System Instruments) with eight culture slots (80 ml), stages, small diatoms and xanthophytes individually illuminated by a set of led light adjustable (Xanthonema, Heterococcus) usually prevailed. Both − − from10to900µmolphotonsm 2 s 1.Eachslotisalso species numbers and abundance rapidly increased equipped by an optical density detector, which measures with increasing successional age reaching more than every hour the turbidity at 750 nm, simplifying the 30 species and abundances typical for temperate soils, evaluation of microalga growth curve. In all the consid- but in the oldest stages showed decreasing tendency. ered conditions, morphology, lipid accumulation, chlor- Cyanobacteria dominated usually in younger succes- ophyll and carotenoid content and photosynthetic sional stages, and their occurrence decreased with activity, have been determined and correlated with the decreasing soil pH, typically in old successional growth rate and biomass production. We also verified stages. Pseudococomyxa, Elliptochloris, the nature of synthetized carotenoids by mass spectro- Chloroidium, Xanthonema, Leptolyngbya spp. metry analyses. They resulted to be mainly canthax- belonged to both most frequent and often dominant anthin, astaxanthin, ketolutein and their esters. Parallel species. The study was supported by EU Programme to the ketocarotenoids accumulation, there was also a [FP7/2007-2013] under grant agreement No 262693 large production of lipids. [INTERACT] and project LD13046 [ME Czech Republic].

9OR.8 9OR.9 SUCCESSION OF ALGAL AND CYANOBACTERIAL COMMUNITIES AFTER ENDOLITHIC CYANOBACTERIA GLACIER RETREATS IN ALPINE - HIGH COMMUNITIES WITHIN EPISODICALLY ARCTIC CLIMATIC ZONES IN NORTHERN DRY WATERFALL TUFA IN A SOUTHERN- EUROPE CENTRAL ALPINE DRY VALLEY (VINSCHGAU, EUROPEAN ALPS) Alena Lukešová ([email protected]) Eugen Rott1 ([email protected]), Rainer Institute of Soil Biology, Biology Centre CAS, v.v.i., Kurmayer2 ([email protected]), Andreas České Budějovice CZ-37005, Czech Republic Holzinger1 ([email protected]) and Diethard Sanders3 ([email protected]) Accelerated melting of glaciers in many arctic and alpine areas due to global warming provides new 1Institute of Botany, Biology Faculty, University of habitats for biota colonization and soil formation and Innsbruck, Innsbruck 6020, Austria; 2Research Keynote and Oral Papers 80

Institute Limnology, Biology Faculty, University of Cyanobacteria are oxygenic photorophic prokaryotes Innsbruck, Mondsee 5310, Austria and 3Geology with a remarkable range of metabolic capabilities, Institute, Faculty of Geo- and Atmorpheric Sciences, morphologies and life styles. Hence, we are studying University of Innsbruck, Innsbruck 6020, Austria to understand the gene structures and functions of these organisms from several stressed habitats of Aside of studies of “Tintenstriche” (= dark pigmented India with an aim to explore their potential for using epilithic phototrophic communities on rock cliffs), in biotechnology. The culture collection at our lab has records of endolithic Cyanobacteria from the European a deposit of >200 species/strains of Cyanobacteria and Alps are rare. We found a microbial community inhabit- many of these have been isolated from several stressed inganepisodicallydry-fallen surface of a waterfall tufa habitats like exterior of stone monuments, building in the Alps, forming one or two distinct black to dark facades and biofilms on sun-scorched soils. All these blue-green permanent endolithic layers in 1-2 mm and taxa have been identified following morphometric 4-6 mm below surface, and at a distance of 1-4 m from protocols, most validated following molecular proto- water-run areas. The waterfall tufa forms from ambient cols, e.g. 16 S rRNA sequencing and further work is (non-thermal) waters during episodes of increased run- currently ongoing at our group to develop an atlas of off. Community structure showing a prevalence of such microbes in a global scenario. Studies are also Cyanobacteria was studied by culture-independent and focused to understand the structural and molecular culture-dependent approaches and covered light-and basis of the organism’s performance under a set of electron microscopy (TEM) and molecular characteriza- environmental conditions by employing few selected tion using 16S rRNA-based clone libraries. Clonal nitrogen fixing Cyanobacteria species under inserts were screened by restriction fragment length Tolypothrix and Scytonema, those survive in desic- polymorphism and individual restriction types were cated state as biofilms on dried soils and exposed sequenced. The limestone was studied in epoxy-impreg- surfaces of building stones in India. In this regard nated, petrographic thin sections under polarized light- using oligonucleotide probes deduced from a con- and dark-field microscopy. Although there is a relation- served region of amino acids of SOD (superoxide ship of the endolithic community to the surface-dwelling dismutase) proteins, a SOD gene was detected in “Tintenstrich” microflora, we found a smaller number of Hassellia byssoidea (formerly Tolypothrix). taxa within the endolithic layers, which seem specifi- Amplification of specific genes of the genomic DNA cally adapted to this microenvironment. The endolithic and sequencing of the PCR product yielded a sodB microbial communities presumably consist mainly of gene of 292 bp size. Southern hybridization confirmed limestone-dissolving taxa rather than bio-calcifying the presence of a single sodB gene in the desiccation taxa. The sub-millimeter sized pore spaces (parallel tolerant cyanobacterium. Another reason for effective underneath the outer calcified surface of the waterfall colonization of these organisms on exposed stones tufa) they inhabit is filled with damp air rather than even under hot summer of the tropics due to presence water; this enables the community to withstand extended of UV-A and B absorbing pigments in their cells and periods of drought as typical of central-alpine valleys their sunscreen role was characterized. Control of during summer. The functional groups of Cyanobacteria epilithic biofilms for arresting biodeterioration and in the endolithon are composed of, both, nitrogen fixers conservation of monuments was studied, however, (Dichothrix sp.) and non-N-fixers (Aphanothece sp.), development of a cost effective method is still in adapted to low-light conditions; in the epilithon high- process. light and desiccation-tolerant taxa were recorded (Gloeocapsa alpina, Gloeocapsopsis sp., Chon drocystis sp.). Nostoc sp., however, was common in the cultures from both habitats. 9OR.11 RESPONSE OF BENTHIC DIATOMS 9OR.10 INHABITING INTERTIDAL FLATS TO ENVIRONMENTAL STRESSES BIODIVERSITY OF STRESS TOLERANT CYANOBACTERIA ON EXPOSED SURFACES Johann Lavaud ([email protected]) OF MONUMENTS OF CULTURAL ’ HERITAGE, THEIR BIODETERIOGENIC Institut du Littoral et de l Environnement, CNRS- ACTIVITY AND POSSIBLE CONTROL FOR Université La rochelle, La Rochelle 17000, France CONSERVATION Intertidal flats belong to the most productive ecosys- Siba Prasad Adhikary ([email protected]) tems, largely owing to the primary production of diverse communities of benthic diatoms. They can Bioscience, Fakir Mohan University, Balasore maintain high levels of photosynthetic productivity 756020, India despite the often harsh environmental conditions that Keynote and Oral Papers 81 can potentially generate intracellular oxidative stress. photoprotective process against photoinhibition. The amplitude and combinations of stresses partly These diatoms use vertical migration to regulate depend on the flat sediment type (typically cohesive light exposure and minimize light stress, a mechan- fine particles versus less cohesive larger particles), isms shown to represent an effective form of beha- that are inhabited by different diatom growth forms. vioural photoprotection. This study compares the Two main growth forms can be distinguished: motile short-term kinetics of the activation of both processes epipelon, which inhabits fine cohesive sediment, and when cells are faced with potentially damaging light smaller, immotile or motile epipsammon which lives levels. Induction kinetics of the xanthophyll cycle was attached to particles in less cohesive sediments. In quantified on suspensions of MPB diatoms, by mea- order to protect their photosynthetic efficiency, suring the activation of non-photochemical quenching benthic diatoms have evolved behavioural and phy- (NPQ) upon exposure to high light (1350 µmol m−2 siological processes. Behavioural processes mainly s−1) using a Pulse Amplitude Modulated (PAM) fluo- rely on the ability of some species to vertically move rometer. Vertical migration was quantified by measur- in the sediment in order to escape stressful conditions. ing the short-term change in surface microalgal Among the physiological processes, the non-photo- biomass on undisturbed sediment samples, using the chemical quenching (NPQ), and the associated optical index NDVI (Normalized Difference xanthophyll conversion (XC) and LHCx protein Vegetation Index). NDVI was measured on samples synthesis, allow the fast regulation and the safely simultaneously exposed to a range of incident irradi- balance of photosynthesis. We have examined the ance levels (50-1350 µmol m−2 s−1), generating ability of representatives of the main growth forms Biomass-Light Curves. This was achieved by using a of benthic diatoms as well as the one of natural com- modified chlorophyll fluorescence imaging system munities to respond to simulated Spring and Summer with red and infrared bandpass filters, in combination potentially stressful conditions of light, temperature with the projection of digitally-controlled, spatially and salinity in combination or not. The results showed separated light beams. The results showed that high that i) the physiological response of benthic diatoms to light-induced vertical migration occurs at a much fas- environmental stresses is mainly related to their habi- ter rate than previously reported, with surface biomass tat and growth form; ii) the high light and high tem- decreasing by more than 35% of total induced change perature are major stresses compared to high salinity. during the first 2.5 min of light exposure. The compar- Our study also highlights the joint role of environ- ison of the induction kinetics of NPQ and vertical mental harsh conditions in limiting transiently (i.e. migration showed that they are activated at compar- during emersion), the photosynthetic productivity of able time scales, indicating a complex interdepen- benthic diatoms in situ. dency in the regulation and operation of the two photoprotection mechanisms.

9OR.12 9OR.13 MINIMIZING EXCESS LIGHT ABSORPTION BY BENTHIC DIATOMS: COMPARATIVE FIFTY YEARS AFTER POWELL: THE KINETICS OF VERTICAL MIGRATION AND DISTRIBUTION OF FUCUS DISTICHUS NON-PHOTOCHEMICAL QUENCHING ANCEPS ON THE EXTREME EXPOSED 1 2 ROCKY SHORES OF ORKNEYAND ITS ROLE João Serôdio ([email protected]), Martin Laviale AS AN INDICATOR SPECIES ([email protected]) and Silja Frankenbach1 ([email protected]) Andrew Want ([email protected]), Michael C Bell ([email protected]) and Jon C Side (j.c.side@hw. 1Department of Biology, University of Aveiro, Aveiro ac.uk) 3810-193, Portugal and 2Observatoire Océanologique, CNRS-UPMC Univ Paris 06, School of Life Sciences, Heriot-Watt University, Villefranche/mer F-06234, France Stromness KW16 3AW, United Kingdom

Microalgae inhabiting intertidal ﬂats are routinely Fucus distichus anceps is a boreal brown alga typi- exposed to high levels of solar radiation for prolonged cally found on exposed mid-littoral rocky shores. The periods. During low tide, the exposure to direct sun- southern-most distribution extends to the north and light combined with extreme temperatures, high sali- west of Scotland and Ireland in often isolated popula- nities and desiccation conditions is prone to cause tions associated with extreme wave energy. In 1957, photoinhibitory damage. Estuarine microphyto- H. Powell published two important papers on the benthos (MPB) is typically dominated by pennate ecology and distribution of F. distichus and updated benthic diatom species that rely on a diadioxanthin- this in 1963 with a more complete description of the diatoxanthin xanthophyll cycle as the main distribution of F. distichus anceps in Orkney and Keynote and Oral Papers 82

Shetland. Since then, only a limited number of macro- France and 5Department of Biotechnology, algal studies have featured this seaweed owing to its Universität für Bodenkultur (BOKU), Vienna 1190, limited geographical range in British waters and the Austria challenges in accessing much of its habitat. Interest however has returned following the identiﬁcation of F. Ectocarpus is a cosmopolitan brown algal genus with distichus anceps as a potential indicator species for high capacity to acclimate to different environments. changes in both climate (most obviously manifested Particularly, wide tolerance ranges were observed as increases in sea surface temperature) and wave with respect to salinity: while most Ectocarpus iso- energy (targeted for extraction by wave energy con- lates are marine, at least one strain (named hereafter verting devices [WECs]). We have established a long- FWS) was isolated in 1996 from a true freshwater term monitoring programme for F. distichus anceps habitat at Hopkins River Falls in Australia. Indeed, while researching the role of wave energy on biologi- the transition from marine environments to freshwater cal community dynamics on the rocky shores of is a particularly rare event in brown algae, and only Orkney – an area where WECs are being tested for about 1% of brown algal species have colonized this large-scale deployment. Our research has included habitat. Additional Ectocarpus isolates closely related many previously unaccessed sites. All the locations to FWS have been found in other “extreme” environ- described by Powell have been revisited and evalu- ments such as on driftwood, or in areas of highly ated; abundance measurements of about 40 rocky variable temperature, and belonged to the clade 2d of shore species (including additional fucoids and impor- the Ectocarpus genus. Very recently, it has been pro- tant grazers) have been recorded; and various topo- posed to reinstate the species E. subulatus for indivi- graphical features associated with littoral wave duals referred to this clade, which is distinct, but exposure have been measured. Topographic variables closely related, to the species corresponding to the include: slope, complexity, aspect and orientation to genome-sequenced strictly marine Ectocarpus (clade fetch. Our research, in combination with Powell’s 1c), both having diverged roughly 16 Mya. The E. records, suggests that the presence/absence of F. dis- subulatus FWS is able to grow in both seawater and tichus anceps at individual site locations is remark- freshwater, showing that the transition towards the ably stable on a temporal scale of decades. On Orkney, latter is not irreversible yet. This euryhaline strain abundance of F. distichus anceps appears primarily to exhibited profound, but reversible, morphological, vary in relation to wave energy. We believe that this physiological, and transcriptomic changes when species is an important indicator of changes in wave transferred between freshwater and seawater, e.g. energy but that its role as a climate change indicator adjusting its metabolism and cell wall structure to has not yet been demonstrated. the corresponding conditions. To elucidate the evolution of the FWS and its phenotypic plasticity, the genome of this strain (diploid) and of one of its close relatives (haploid) have been sequenced, and com- 9OR.14 parative analysis with this of the marine Ectocarpus COMPARATIVE ANALYSIS OF MARINE AND is underway. Finally, we have shown recently that the FRESHWATER BROWN ALGAE: INSIGHTS ability of the FWS to grow in freshwater is strictly INTO THE BIOLOGY AND EVOLUTION OF dependant of its associated phycosphere. Therefore, AN EXTREMOPHILE ECTOCARPUS the FWS and its related microﬂora form an interesting 1 biological system useful to assess how aquatic photo- Simon M Dittami ([email protected]), Irene 2 synthetic holobionts behave to face changes in envir- González ([email protected]), André E 3 onmental conditions. Minoche ([email protected]), Noé Pontoizeau1 ([email protected]), Alexandre Cormier1 ([email protected]), Erwan Corre4 ([email protected]), Catherine Boyen1 9OR.15 5 ([email protected]), Heinz Himmelbauer (heinz. ULVA INTESTINALIS 1 HOW CAN RESIST THE [email protected]) and Thierry Tonon SUNLIGHT WHILE FLOATING ON THE SEA ([email protected]) SURFACE? 1Sorbonne Universités, UPMC Univ Paris 06, CNRS, Frauke Pescheck ([email protected]), Hanna UMR 8227, Integrative Biology of Marine Models, Campen ([email protected]), Lars Nichelmann Station Biologique, Roscoff 29680, France; 2Centre ([email protected]) and Wolfgang Bilger for Genomic Regulation (CRG),, Barcelona 08003, ([email protected]) Spain; 3Centre for Genomic Regulation (CRG), Barcelona 08003, Spain; 4ABiMS platform, FR 2424 Botanical Institute, Christian-Albrechts-University, CNRS UPMC, Station Biologique, Roscoff 29680, Kiel 24118, Germany Keynote and Oral Papers 83

– The green macroalga Ulva intestinalis is a key species were investigated. We hypothesized that: (1) NO3 – of the upper intertidal zone often forming dense assimilation, the size of the internal NO3 pool, and – stands. The morphology with unbranched, partially total tissue N content, will depend on NO3 supply and fi fl gas lled tubes oating on the water surface renders (2) a higher CO2 concentration will increase photo- it a true high-light plant which is exposed to unatte- synthesis and growth of Macrocystis, coupled with an – nuated sunlight not only during low tide. Despite this increase in NO3 uptake and assimilation. Macrocystis regular sunlight exposure U. intestinalis contains no discs were first grown under low (5 µM) and high (80 – – – protective ultraviolet-B (UVB, 280 315 nm) screen- µM) NO3 concentrations so that internal NO3 pools ing pigments. It was examined how U. intestinalis were either nitrate deplete or replete. The discs were copes with the high intensity of photosynthetically subsequently grown under current (400 µatm; pH active radiation (PAR) and with the concomitant 8.05) and future (1200 µatm; pH 7.59) CO2 concen- – high dose of UVB of sunlight on several daily courses trations, with 20 µM NO3 . After 3 days, the total in situ and a long-term study in mesocosms. Our tissue N content, nitrate reductase (NR) activity, – – results show a remarkable potential of down regula- NO3 uptake, and internal NO3 pool were completely fi – tion of photosystem II (PS II) ef ciency indicated by a modulated by the NO3 concentration in seawater. NR fl – substantial quench of ground uorescence (FO). activity, internal NO3 pool and total tissue N content Moreover, the recovery kinetics of PS II efficiency were reduced for discs initially grown under low – during the afternoons showed no delay implying a fast [NO3 ]. An additional 3 day incubation in the CO2 reversible photoinhibition. In addition, the regenera- treatments had no effect on photosynthetic rates, tion of photodamaged PS II seems to be very efficient growth rate, and NR activity, irrespective of the size – – in U. intestinalis. Inhibitor studies after a UVB chal- of the internal NO3 pool. However, higher NO3 – lenge revealed a very high capacity of PS II recovery uptake and internal NO3 pools were observed under by protein synthesis in this alga, being 4 times higher elevated CO2, but only in discs with an depleted – than in three other green macroalgae from the eulit- internal NO3 pool. Results show that increased CO2 toral. In summary, protective down regulation and did not enhance either photosynthesis or growth of – repair processes act together to render the photosynth- Macrocystis, and NO3 assimilation was mainly regu- – – esis of U. intestinalis resistant against high PAR and lated by NO3 availability. However, the higher NO3 UVB intensities. Surprisingly, no accumulation of uptake observed in N-deplete blades indicates that N UVB-induced DNA damage was detectable in the status may modulate the physiological responses of field although the solar irradiation was maximal for Macrocystis to OA. Northern Germany. From preliminary results we hypothesize that the photoreactivation of DNA dimers plays a crucial role for the DNA stability of U. intes- 9OR.17 tinalis under solar irradiation. THE ALGA THAT NEVER READ THE LITERATURE - FASTEST GROWING, DESICCATION AND PHOTODAMAGE 9OR.16 TOLERANT ALGA, ISOLATED FROM THE PHYSIOLOGICAL RESPONSES OF DESERT CRUST GIANT KELP MACROCYSTIS PYRIFERA TO Haim Treves ([email protected]) OCEAN ACIDIFICATION ARE MODULATED BY INTERNAL NITROGEN STATUS Plant and Environmental Sciences, Hebrew Pamela A Fernandez1 (pamela.fernandez@botany. University of Jerusalem, Jerusalem 91904, Israel otago.ac.nz), Michael Y Roleda2 (michael.roleda @bioforsk.no), Catriona L Hurd3 (catriona.hurd After many years of research, some feel that we have @utas.edu.au) and Pablo P Leal1 (leal_sandova elucidated the functioning of the photosynthetic [email protected]) machinery and limitations therein, and what sets the upper limit for algal growth. However, the unparal- 1Botany, University of Otago, Dunedin 9016, New leled fast growth, extremely high photosynthetic rates Zealand; 2Bioforsk, Norwegian Institute for and resistance to photodamage, salinity and desicca- Agricultural and Environmental Research, Bodø tion displayed by C. ohadii, recently isolated from a 8049, Norway and 3Marine and Antartic, Institute for biological desert sand crust (BSC), one of the harshest Marine and Antarctic Studies (IMAS) University of environments to support life, suggest this may not be Tasmania, Hobart 7004, Australia the case. When grown under optimal laboratory or controlled outdoor facility conditions it exhibits the The combined effects of elevated CO2 (aq) and nitrate fastest growth rates ever reported for an alga. The – (NO3 ) supply on the carbon and the nitrogen physiol- cultures perform among the highest photosynthetic ogy of Macrocystis pyrifera (hereafter Macrocystis) rates ever reported and reach very high cell densities Keynote and Oral Papers 84

(1.3*109 cells/mL). When grown in photo-bioreactors transported to Sweden for chemical analyses. Over under optimal conditions, division times as short as three weeks in ambient radiation, preliminary results 1.2 h were recorded. To the best of our knowledge it is from PAM measurements and cell numbers show that the fastest growth rate ever reported for a photosyn- the microbial community were tolerant to both ultra- thetic organism and close to the maximal attained by violet-A and ultraviolet-B radiation (reflected in total unicellular eukaryotes. Unlike other photosynthetic cell numbers and photosynthetic activity, Fv/Fm). organisms, C. ohadii productivity is unaffected by Photosynthetic pigment and species/genera composi- irradiances as high as twice full sun light; and the tion remains to be analysed. Furthermore, rapidly level of protein D1, encoded by a single gene in the increasing salinity from freshwater to salinity 30 did C. ohadii genome (56 MB), is hardly affected. not have any effect on photosynthetic activity (Fv/Fm) Following exposure to high irradiance, C. ohadii over nine days. This suggests that parts of the melt- cells undergo major structural (i.e. pyrenoid develop- water microbial mats may survive when flushed out in ment and increased thylakoid abundance) and compo- seawater and could contribute to primary production sitional changes (i.e. a 2-3 fold increase of the lipid in Potter Cove. In conclusion, our preliminary results and carbohydrate contents). In view of the unparal- confirm that these microbial mats show a remarkable leled growth and photosynthetic performance, C. oha- tolerance to extreme environmental conditions and are dii may be used in future research to clarify the most likely survivors also in a rapidly changing cli- processes that rate-limit growth and productivity of mate at South Shetland Islands. photosynthetic organisms. In an era where novel approaches to raise biomass production for food or energy supply are explored, C. ohadii may be used 9OR.19 either directly in algal farms or as a gene source for the development of crop plants that can maintain high EXPRESSION OF GENETIC TRANSPOSABLE yields in environments not suited to current cultivars. ELEMENTS UNDER THERMAL STRESS IN THE DIATOM PHAEODACTYLUM TRICORNUTUM

9OR.18 Fadoumo Egue ([email protected]), Emmanuelle Tastard (emmanuelle.tastard@univ- AUTOTROPHS IN ANTARCTIC MELTWATER lemans.fr), Benoît Chenais (benoit.chenais@univ- MICROBIAL MATS - THE TOUGH lemans.fr), Annick Morant-Manceau (annick.man SURVIVORS [email protected]), Nathalie Casse (nathalie.cas Angela Wulff ([email protected])andAnders [email protected]) and Aurore Caruso (aurore.caru Torstensson ([email protected]) [email protected])

Biological and Environmental Sciences, University of Laboratoire Mer, Molécules, Santé (EA 2160), Gothenburg, Göteborg SE40530, Sweden Université du Maine, LE MANS 72085, France

Autotrophs inhabiting polar meltwater microbial mats A significant part of virtually all genomes is made of are exposed to extreme environmental conditions. genetic transposable elements (TEs) that are segments These extreme conditions include large fluctuations of DNA encoding enzymes that mediate their move in ambient radiation (including ultraviolet radiation), within genomes. Most of them are inactive because of temperature, salinity and desiccation. We studied accumulated mutations but some of them are poten- microbial mats growing in meltwater streams (water tially active and may be mobilized, particularly in depth varying between 0.5 and 2 cm) close to Potter stressful conditions. Such mobilization is often harm- Cove, King George Island, January to February 2015. ful for the individual but promotes adaptability for the The dominating autotrophs were pennate diatoms and species since the mobility of those elements brings cyanobacteria. In four different experiments, the genetic diversity and largely contributes to genome effects of ultraviolet radiation, temperature (freezing), evolution. Retrotransposons constitute a category of elevated salinity and desiccation were tested in labora- TEs that are particularly reactive to stressful condi- tory and outdoor set-ups. Measured variables differed tions. Phytoplankton is subjected to variation in tem- between experiments and included photosynthetic perature that will keep increasing because of climate activity (pulse amplitude modulated fluorometry, change. We analyzed the transcriptomic expression, in PAM), non-photochemical quenching (PAM), rapid condition of thermal stress, of two retrotransposons light curves (PAM), species/genera identification, bio- previously characterized in the diatom Phaeo volume and growth (microscopy), photosynthetic pig- dactylum tricornutum: Blackbeard and Surcouf. ments (HPLC), lipid peroxidation (thiobarbituric acid Whereas the expression of Blackbeard was not reactive substances (TBARs) assay) and biomass of affected by thermal stress, Surcouf was overexpressed heterotrophic bacteria. Samples are currently at high temperature, just as small Heat Shock Proteins Keynote and Oral Papers 85

(sHSP). We searched Heat Shock Response motifs in tions (floods versus droughts). To understand the sHSP promoters and in the 5’ DNA sequences - how the alga adapted to survive and reproduce that are equivalent to promoters - of both retrotran- in this environment, we used axenic cultures, sposons. Heat Shock Elements (HSEs), Stress simulated the above-listed stresses and studied Response Elements (STREs) and/or CCAAT boxes their effect on the alga’s life history. We found were identified in the sequences of sHSP promoters that despite its relatively simple morphology (i.e. and in the 5’ DNA sequence of Surcouf, but not in that a uniseriate filament with intercalary cell divi- of Blackbeard. This result suggests that sHSP and sions), the alga adapted to the fluctuating envir- Surcouf might be partly co-regulated and explains onment of the canyon through specific life-history the overexpression of Surcouf at high temperature. traits. (1) Aplanospores enable survival during long drought periods, spreading during floods, and subsequent rapid (re)colonization due to abnormal first cell divisions in germlings leading 9OR.20 to the formation of two or even several filaments A NEW GREEN ALGAL LINEAGE ISOLATED from one aplanospore. (2) Fragmentation through FROM A VOLCANIC CANYON IN THE ˈfilament splittingˈ (a unique mechanism, not CANARY ISLANDS reported before in green algae and initiated by 1 formation of oblique cross walls) that takes Lenka Caisová ([email protected]), Carolina 2 place when the canyon begins to dry out (branch Pérez Reyes ([email protected]), 2 formation) and floods/heavy rain showers occur Virginia Cruz Álamo (vcruz@marinebiotechnology. 2 (fragmentation). (3) Besides that, the alga repro- org), Antera Martel Quintana (amartel@marinebio 1 duces asexually during an aquatic life stage by technology.org), Barbara Surek (barbara.melkonia 1 zoospores (numbers of flagella per zoospore differ [email protected]) and Michael Melkonian (michael. from 4-24) and may spread and thus maximize [email protected]) colonization during post-flood periods when sub- 1Botanisches Institut, Universität zu Köln, Köln merged. Since the observed life history traits 50674, Germany and 2Spanish Bank of Algae – could not be assigned to a described taxon, we Marine Biotechnology Center, University of Las examined the phylogenetic position of this organ- Palmas de Gran Canaria, Telde, Las Palmas, Gran ism. Interestingly, we found that the alga repre- Canaria 35214, Spain sents a novel lineage at the genus and family level in the Chaetophorales (Chlorophyceae). In fi Algae are one of the most diverse and highly conclusion, our ndings clearly indicate that the ‘ ’ adapted forms of life on Earth. Here, we report study of non-typical habitatscanhelptodis- the discovery of a terrestrial green alga isolated cover novel microalgal diversity and provide from a peculiar habitat in La Palma (Canary new insights into evolutionary processes that Islands, Spain) – a steep volcanic canyon that is have shaped adaptations of such algae to their fi constantly exposed to changing weather condi- speci c habitat. Keynote and Oral Papers 86

10. Global change and algal assemblages: the fate of our seas

10KN.1 dynamics). To explore the role of eco-evolutionary VANISHINGFORESTS OF CANOPYALGAE: A dynamics and their effects on selection over time, we GLOBAL PROBLEM WITH LOCAL conducted a series of experimental evolution studies SOLUTIONS? using an algal host and its virus. We will present results from experiments where we compared the evolutionary Laura Airoldi ([email protected]) and ecological dynamics of experiments when host and virus coevolved with and without an additional predator Dipartimento di Scienze Biologiche, Geologiche ed in the system. We found that predator and virus could Ambientali, University of Bologna, Ravenna 48123, only coexist after the host evolved a general resistance Italy against the virus and that coexistence of the two consumers shifted the ecological dynamics towards cyclic Canopy-forming seaweeds are severely retracting populations compared to the experiments with only host globally, particularly in urban areas, and are replaced and virus. Most importantly, the presence of the predator by turf-forming algae or sea urchin barrens. Those changed the evolutionary dynamics from fluctuating forests that remain are under continued and under- selection when host and virus evolve alone, to constant estimated threat, and the overall benefits of current selection when virus and predator coexisted. Overall, protection measures have been low. I analyse the our study shows the important consequences of rapid drivers of loss of these highly threatened and valuable evolutionary change and highlights that the details of ecosystems. These involve complex interactions coevolutionary dynamics matter for community stability between multiple local (nutrient enrichment and high (cycles vs. stability) and structure (coexistence or not), sediment loads, fishing, heavy metal pollution) and which in return determines type of selection (fluctuating global stressors (increasing temperature, high wave vs. constant). exposure, and high UV or CO2). While many of the effects of global threats will continue for decades, if not centuries, experiments suggest that the control of 10OR.1 local stressors could work as a rapid and cost-effective INVESTIGATING TEMPORAL CHANGES IN strategy to limit at least some of the adverse effects, SEAWEED COMMUNITIES OF BRITTANY allowing more time to these ecosystem to adjust to 1 1 climate change. A resilience approach to limit the Line Le Gall ([email protected]), Marine Robuchon ([email protected]), Régis Gallon2 (reg.gallon impacts of global climate changes by managing syner- 3 gies between global and local stressors is illustrated @gmail.com), Boris Leroy (leroy.boris@gmail. com), Eric Feunteun4 ([email protected]) and with reference to the experience developed within 5 project TETRIS (Observing, modelling and Testing Myriam Valero ([email protected]) synergies and TRade-offs for the adaptive manage- 1 ment of multiple Impacts in coastal Systems). Systematique & Evolution, Institut de Systématique, Evolution, Biodiversité, ISYEB - UMR 7205 - CNRS, MNHN, UPMC, EPHE, Paris 75231, France; 2CNRS 10KN.2 (ANR BenthoVAL), UMS 3113 - OSU IUEM LEMAR UMR6539 CNRS | UBO | IRD | IFREMER, ECO-EVOLUTIONARY DYNAMICS IN PLOUZANÉ 29280, France; 3DMPA, UMR Biologie PLANKTON COMMUNITIES des Organismes et des Ecosystèmes Aquatiques, Paris 4 Lutz Becks ([email protected]) 75231, France; DMPA, UMR 7208 Biologie des Organismes et Ecosystemes Aquatiques (MNHN- Community Dynamics Group, Depart. Evolutionary CNRSUPMC-IRD), Centre de Recherche et Ecology, Max Planck Institute for Evolutionary d’Enseignement sur les Systemes Cotiers, Museum Biology, Plön 24306, Germany National d’Histoire Naturelle,, Dinard 35800, France and 5Station Biologique de Roscoff, UMI 3614 Coevolutionary changes in antagonistic interacting Evolutionary Biology and Ecology of Algae, CNRS, populations can constantly change the mode, strength Sorbonne Universités UPMC Univ. Paris 06, and direction of selection through the link between the Pontificia Universidad Católica de Chile, ecological and evolutionary dynamics (eco-evolutionary Universidad Austral de Chile, Roscoff 29688, France Keynote and Oral Papers 87

Brittany is a hotspot of macro algal biodiversity highlighted significant cryptic diversity within the located at the confluence of the lusitanic and the boreal genus and demonstrated the cosmopolitan distribu- ecoregion. Population genetic studies have shown that tion of C. caespitosa in contrast to the restricted it was a refugium for macro algae during the Last North Atlantic distribution of C. officinalis. Glacial Maximum. Our study of evolution of coastal Corallina species were shown to experience signifi- water temperature in Brittany showed that the tem- cant seasonal and tidal fluctuations in abiotic con- perature increased by 0.7 °C on average over the past ditions, which may infer resilience to future change two decades (0.35 °C per decade). At a finer scale, in seawater acidity, carbonate saturation and water changes in SST showed that Brittany constitutes a temperature. Productivity, calcification and growth mosaic of contrasting conditions, with the western followed seasonal cycles in abiotic parameters, and north-western regions being colder and less although decreasing growth was observed with affected by climate change than the other three increasing latitude. Seasonal cycles in skeletal Mg regions. We analysed changes in macro algal commu- incorporation were apparent, with a strong positive nities by i) assessing turn over of subtidal red seaweed relationship to sea surface temperature, although no assemblages over the 20-year period and ii) modelling significant change in skeletal mineralogy was evi- distribution changes for selected species with species dent in herbaria collections spanning from pre- distribution models, iii) evaluating from natural his- industrial times to the present. Overall, these find- tory collection accommodated in marine stations the ings indicate that Corallina species have the poten- sweep and the tempo of those changes over 200 years. tial to survive under future acidification and ocean warming conditions, although loss of populations from higher latitudes and shifts in the relative abun- 10OR.2 dance of species across lower latitudes of the NE Atlantic are projected. NE ATLANTIC CORALLINA (RHODOPHYTA) IN A HIGH CO2 WORLD Chris J Williamson1 ([email protected]), 10OR.3 Marian Yallop2 ([email protected]), 3 THE WEAKEST LINK: ARE THE Rupert Perkins ([email protected]) and Juliet 4 MICROSCOPIC STAGES OF SEAWEEDS Brodie ([email protected]) MOST SUSCEPTIBLE TO CLIMATE 1Life Sciences, The Natural History Museum, London CHANGE? SW7 5BD, United Kingdom; 2School of Biological Michael Y Roleda ([email protected]) Sciences, Bristol University, Bristol BS81TQ, United Kingdom; 3School of Earth and Ocean Science, Bioforsk Nord Bodø, Norwegian Institute for Cardiff University, Cardiff CF10 3AT, United Agricultural and Environmental Research, Bodø Kingdom and 4Life Sciences Department, The Natural 8049, Norway History Museum, London SW7 5BD, United Kingdom Seaweeds are foundation species that provide 3- A comprehensive study of the phylogenetics and dimensional habitat and food for invertebrates and ecophysiology of species of the calcified red algal fish. All seaweeds have complex life cycles, with genus Corallina was undertaken across the NE unicellular and microscopic cryptic stages that may Atlantic to provide projections of the fate of these be more vulnerable to climate change than their cor- ecosystem engineers under a high CO2 world. responding adult stages upon which most research has Corallina species are ubiquitous in temperate inter- focussed. There has been virtually no comprehensive tidal habitats, although they are predicted to be research on the interactive effects of different climate particularly vulnerable to the impacts of ocean acid- change stressors on the survivorship of these micro- ification and ocean warming. The establishment of scopic stages of seaweeds, nor studies on physiologi- clear species concepts for Corallina present in the cal or biochemical mechanisms that might confer an NE Atlantic facilitated a subsequent phylogenetic ability to acclimate to climate change. This lack of study that explored species diversity, distributions research on microstages is surprising given that they and the extent to which names have been misap- are the seed bank for the next generation of the eco- plied. From this baseline, investigations into the system-engineering macroscopic population, and that ecophysiology (productivity, calcification, growth change in the viability of microscopic stages and and skeletal mineralogy) of C. officinalis and C. decrease in their recruitment success will have pro- caespitosa were performed across the NE Atlantic found flow-on effects to the macroscopic community (Iceland to northern Spain) in relation to temporal and the ecosystem they support. Knowledge on spe- and spatial fluctuations and gradients in tempera- cies’ survival thresholds is key in preserving marine ture, irradiance and carbonate chemistry. Results biodiversity. Keynote and Oral Papers 88

10OR.4 Rising levels of atmospheric CO2 and increasing tem- INSIGHTS FROM OSTREOCOCCUS INTO peratures altered ocean climate with well documented harmful effects on marine ecosystems. In the case of COPING IN A SEA OF VIRUSES AND fi COMPETITORS seaweeds, ocean warming and acidi cation have large effects not only on their metabolic rates and popula- Sheree Yau ([email protected]) tion dynamics, but also on the way they interact with other trophic levels like seaweed grazers. Given the Integrative Biology of Marine Organisms, Banyuls importance of top-down effects on the regulation of Oceanologic Observatory, Banyuls-sur-Mer 66650, seaweed assemblages, predicting the ecological France impacts of ocean climate change requires not only studies on the ecophysiological effects but also The smallest free-living eukaryotes are picoalgae of the research on species interactions. Here we present a genus Ostreococcus, which measure less than 1 um set of studies aimed to understand how the combined diameter. Four clades based on 18S ribosomal gene effects of seawater warming and acidification shape fi phylogeny (A-D) have been de ned based on >98% seaweed assemblages and their herbivore interactions. nucleotide identity that correspond with coastal, sur- We carried out a set of mesocosm experiments includ- face ocean and deep ocean ecotypes. The genetic dis- ing crossed treatments of pH and temperature where tance between these clades in the rest of the genome is we measured short term functional responses of dif- enormous with orthologous genes sharing 72% identity ferent species of seaweeds and grazers to future envir- [3]. Molecular phylogeny and karotyping indicates the onmental conditions and also changes on the intensity fi 18S-de ned clades represent distinct species, and not of macroalgae-herbivore interactions. Our results simply ecotypes. Despite this large genetic diversity, showed that species response to ocean climate change Ostreococcus species are morphologically indistin- were non–linear and differed among species. Also guishable. The type species, O. tauri (clade C) and synergistic interactions among physical drivers many the newly described species, O. mediterraneus (clade hinder our ability to predict the future impacts of D) appear to both be most abundant in coastal climate change. Mediterranean lagoons. However, phylogenomics indicates O. mediterraneus is the deepest branching lineage within Ostreococcus. Genome sequencing of O. med- 10OR.6 iterraneus was performed to determine the expanded RECOVERY OF CYSTOSEIRA FORESTS gene families, unique genes in this species and gain ALONG THE WEST ISTRIAN COAST insight into the evolution of the genus. From transcrip- (NORTHERN ADRIATIC SEA, CROATIA) tomes of several strains of O. mediterraneus,the nucleotide diversity estimated was consistent with Ljiljana Iveša([email protected]) and Tamara levels in intraspecies populations. Positive tests for Djakovac ([email protected]) recombination indicate O. mediterraneus occurs as a distinct panmictically breeding species. Surprisingly, Center for Marine Research, Ruđer Bošković the type strain of O. mediterraneus chronically pro- Institute, Rovinj 52210, Croatia duces infective viruses but is not lysed. These data shed light into how sympatry has evolved in Ostreococcus The west Istrian Coast delimits the eastern border of and implicates a role for viruses. the northern Adriatic Sea. Because of increased levels of nutrients due to runoffs from the Italian rivers, the northern Adriatic is one of the most eutrophicated 10OR.5 regions of the Mediterranean Sea. In total, eight WARM & ACID: CHANGES ON SPECIES Cystoseira species were historically recorded along INTERACTIONS IN THE NEW OCEAN the west Istrian Coast during the middle of the past century (Cystoseira amentacea, C. barbata, C. com- 1 Francisco Arenas ([email protected]), Maria Jose pressa, C. corniculata, C. crinita, C. foeniculacea, C. 1 Araujo ([email protected]), Eduardo humilis and C. spinosa). Historical data show that 1 Sampaio ([email protected]), David approximately from 1975 to 1990 Cystoseira popula- 1 2 Calvao ([email protected]), Ivan Rodil tions were in a phase of regression because of 1 ([email protected]) and Joao Franco (joao increased eutrophication levels and sea urchin graz- [email protected]) ing. A decreasing trend of river runoffs and the pro- hibition of phosphate-based detergents during 1980s 1Aquatic Ecology & Evolution Group, CIIMAR, Porto 2 produced an oligotrophication of the northern 4050-123, Portugal and Aquatic Ecology & Adriatic. Concomitantly with the decrease in eutro- Evolution Group, CIIMAR, CIIMAR 4050-123, phication levels and a decrease of sea urchin popula- Portugal tions, Cystoseira spp. recovered so that monospecific Keynote and Oral Papers 89 and mixed Cystoseira forests have recolonized the the coast of Rio de Janeiro City, Southeast Brazil. We majority of rocky bottom habitats of the west Istrian focused in the small eukaryote algae (<10 µm) as they Coast after year 2000. The recovery occurred in spite are usually important components of phytoplankton of the fact that nearly each year from 1989 to 2004 communities in brackish coastal lagoons but seldom massive mucilage aggregations have formed in the considered when assessing their environmental stabi- water column of the northern Adriatic provoking lity. Samples were collected twice a week from mass mortality of macrozoobenthos species. It could January 2012 to December 2013 at five sampling be suggested that the decrease of sea urchin density stations. A quick temporal turnover of species (few was a consequence of the mucilage impact. On the days) was observed as well as the absence of a stable contrary, northern Adriatic Cystoseira spp. seems to and recurrent seasonality (global R = 0.8, p = 0,01). be adapted to cope with the mucilage phenomenon. In As a result, phytoplankton assemblages in the RFL did general, Cystoseira forests are in a phase of regression not return to their starting point after a year, but all over the Mediterranean Sea. The assessed recovery followed a path that can remove them far from their is likely related to the particular oceanographic and initial point. Temperature, salinity and NH4 were the ecological characteristics of the northern Adriatic. main abiotic variables explaining the observed temporal variability. High values of temporal beta diversity reported here are consistent with degraded 10OR.7 habitats, subject to rapid environmental changes. TEMPORAL BETA-DIVERSITY OF SMALL EUKARYOTE PHYTOPLANKTON IN A 10OR.8 EUTROPHIZED TROPICAL COASTAL LAGOON EFFECTS OF WARMING AND ACIDIFICATION ON A BENTHIC Catharina Alves-de-Souza1 ([email protected]), COMMUNITY IN THE BALTIC SEA – KIEL Tatiane Benevides1 ([email protected]), Juliana BENTHOCOSMS Barreto1 ([email protected]), Peter Von Dassow2 ([email protected]), Laure Guillou3 Angelika Graiff1 ([email protected]), ([email protected]) and Mariângela Balsam Al Janabi2 ([email protected]), Harald Menezes1 ([email protected]) Asmus3 ([email protected]), Ragnhild Asmus3 ([email protected]), Inka Bartsch4 (Inka. 1Botany Departament, Museu Nacional/Universidade [email protected]), Florian Böhm5 (fboehm@geomar. Federal do Rio de Janeiro, Rio de Janeiro 20940-040, de), Michael Böttcher6 (michael.boettcher@io- Brazil; 2Ecology Departament, Pontificia warnemuende.de), Anton Eisenhauer5 (aeisen Universidad Católica de Chile, Santiago 000000, [email protected]), Lars Gutow7 (Lars.Gutow@awi. Chile and 3UMR 7144, Université Pierre et Marie de), Ulf Karsten1 ([email protected]), Inken Curie/Station Biologique de Roscoff, Roscoff 29680, Kruse2 ([email protected]), Birte Matthiessen8 France ([email protected]), Birte Mensch9 ([email protected]), Andreas Pansch10 Monitoring of coastal-ecosystem health requires indi- ([email protected]), Stefanie Raddatz11 (sso cators of community structure and function. The phy- [email protected]), Ruth Schmitz-Streit9 (rschmitz toplankton community index (PCI) considers the @ifam.uni-kiel.de), Isabelle Tauber12 (itaubner seasonal variation of the community within a multi- @geomar.de), Martin Wahl13 ([email protected]), variate space taking into account a reference envelope Franziska Julie Werner14 ([email protected]) and (with a ring-shaped envelope indicating a resilient Vera Winde6 ([email protected]) ecosystem that quickly returns to its “natural” state after small perturbations). However, whether this con- 1Applied Ecology and Phycology, Rostock University, cept could be applied in tropical habitats, with less Rostock 18059, Germany; 2Benthic Ecology, marked seasonality, was never tested. Here, the tem- GEOMAR Helmholtz Centre for Ocean Research Kiel, poral beta-diversity (i.e., the turnover of species over Kiel 24105, Germany; 3Wattenmeerstation Sylt, time) was used as a proxy of the PCI by using Non- Alfred Wegener Institute, List /Sylt 25992, Germany; metric Multidimensional Scaling (NMDS) coupled 4Biology of Macroalgae, Alfred-Wegener-Institute, with analysis of similarities (ANOSIM), where R Bremerhaven 27570, Germany; 5Marine Geosysteme, values closer to 1 denote a quick temporal species GEOMAR Helmholtz Centre for Ocean Research Kiel, turnover. We combined microscopic analysis and Kiel 24148, Germany; 6Geochemistry and Stable 18S rRNA sequencing (cultures and clone libraries) Isotope Biogeochemistry, Leibniz-Institute for Baltic to assess the phytoplankton temporal beta-diversity in Sea Research, Rostock 18119, Germany; 7 Functional Rodrigo de Freitas Lagoon (RFL), an important urban Ecology, Alfred-Wegener-Institute, Bremerhaven system subject to an intense anthropogenic impact at 27570, Germany; 8Marine Ecology, GEOMAR Keynote and Oral Papers 90

Helmholtz Centre for Ocean Research Kiel, Kiel 10OR.9 24105, Germany; 9Microbiology, Kiel University, RECENT PROGRESS IN THE PHYSIOLOGY, Kiel 24118, Germany; 10Wattenmeerstation Sylt, MINERALOGY AND ECOLOGY OF Alfred-Wegener-Institut, List /Sylt 25992, Germany; CORALLINE ALGAE IN THE GREAT 11Benthic Ecology, GEOMAR Helmholtz Centre for BARRIER REEF AND IMPACTS OF FUTURE Ocean Research Kiel, Kiel 24105, Germany; OCEAN CHANGE 12Marine Geosysteme, GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel 24148, Germany; Guillermo Diaz-Pulido1 (g.diaz-pulido@griffith.edu. 13Benthic Ecology, GEOMAR Helmholtz Centre for au), Emma V Kennedy1 (emma.kennedy@griffith. Ocean Research Kiel, Kiel 24105, Germany and edu.au), Merinda C Nash2 ([email protected]. 14Marine Ecology, GEOMAR Helmholtz Centre for au), Bonnie Lewis1 (bonnie.lewis@griffithuni.edu. Ocean Research Kiel, Kiel 24105, Germany au) and Alexandra Ordoñez1 (alexandra.ordonezal varez@griffithuni.edu.au) Changes in global temperature and ocean chem- 1 istry associated with increasing CO2-concentra- School of Environment & Australian Rivers Institute tions are the most wide-spread effects of climate – Coast & Estuaries, Griffith University, Nathan, change. Numerous studies have shown the impact Brisbane QLD 4111, Australia and 2Research School of single stressors on individual species. of Physics, The Australian National University, However, the combined effect of multiple stres- Canberra ACT 0200, Australia sors on a multi-species assemblage, which are ecologically much more realistic and relevant, Crustose coralline algae (CCA) play important roles in are still missing. Therefore, within the framework tropical and temperate reefs. CCA contribute to coral of the German BIOACID project, we orthogon- reef growth and cementation and are pivotal for reef allycrossedthetwofactorswarmingandacidifi- resilience by inducing coral larval settlement. cation in Benthocosm experiments and studied However, CCA are sensitive to human-induced ocean their single and combined impact on the keystone acidification and warming. Given the importance of brown alga Fucus vesiculosus and its associated CCA for marine systems and the concerns about the community in the Baltic Sea in all seasons (from impacts of projected oceanic change on CCA, we have April 2013 to April 2014). Importantly, to take developed a research program to address key knowledge into account the natural fluctuations of all envir- gaps on the physiology, skeletal mineralogy and ecology onmental variables we superimposed our treat- of CCA in the Great Barrier Reef (GBR), Australia. In ment factors onto these in the benthocosms. For particular, our research focusses on improving our that reason we worked with delta-treatments in all understanding of the effects of elevated pCO2 and tem- seasons, i.e. ambient Kiel Fjord temperature plus perature on CCA and the mechanisms by which these the predicted 5 °C of warming by the end of the effects occur. In this talk we will provide a summary of century and the ambient pCO2 plus the predicted the research we have conducted on these topics in the change (+600 ppm) for the year 2100. In all last few years and will give an update on the projects we seasons, temperature and, to a much lesser extent, are currently doing in the GBR. I will present informa- CO2 affected adult and juvenile F. vesiculosus tion on the physiological responses of early life stages of physiology (growth, photosynthesis) including its CCA to elevated pCO2 and interaction with other fac- associated epiphytes, biofilm and/or mesograzers. tors. Further, I will discuss issues related to the varia- Late summer turned out to be the critical season bility in skeletal mineralogy among reef habitats and for temperature impacts on the entire Fucus sys- discuss how the mineralogical composition varies in tem. Epiphytes showed massive growth, which response to changes in pCO2 and temperature under accelerated a die-off of F. vesiculosus.Theepi- experimental conditions. We have advanced our knowl- phytic overgrowth could indirectly be explained edge on how the process of calcification responds to by temperature–driven reduced top-down control, changes in seawater carbonate chemistry and the exist- because the main mesograzer species declined ing inter-specific variability in the group. However, very under high temperature during summer as well. little is known about the variability in net and gross Understanding responses of macroalgae and of calcification rates directly in the natural environment, the associated community is important because and especially the interactions with water. changing global temperatures and elevated CO2 Understanding the nature and magnitude of the may affect the ecological role of F. vesiculosus responses of CCA to future ocean change will help us as primary producer, carbon sink, water purifier, to assess whether coralline algae will continue to build and ecosystem engineer in the coastal ecosystem and stabilise coral reefs as CO2 rises, crucial information of the Baltic Sea. for environmental management agencies. Keynote and Oral Papers 91

10OR.10 Polar regions are hotspots of climate change, which inevitably also affects seaweed biodiversity by sea ice ARE THERE ANYALIEN MARINE DIATOMS? recession, increased iceberg scouring, and increased David G Mann ([email protected]) inputs of glacial melt water, all of which can have major impacts on phytobenthic communities. Aquatic Ecosystems, Institute for Food and However, any studies of the polar phytobenthos in Agricultural Research and Technology (IRTA), Sant this context confront major challenges in terms of (1) Carles de la Ràpita E-43540, Spain scarce historic baseline datasets and (2) environmental and logistical constraints for scientific collections, and The last 30 years have witnessed a major shift in think- in situ observations by diving. This paper presents ing about diatom biogeography, from an earlier percep- highlights from our expeditions to northern Baffin tion that most species are widely distributed, at least Island (Canadian Arctic, 2009) and Adelaide Island within a broad climatic zone, to one in which species (Antarctica, 2010-2011) which assessed the biodiver- are assumed endemic to a region or island until proved sity of seaweeds and associated eukaryotic pathogens otherwise. In part, this change is correlated with a shift to at established study sites. Our dataset provides a base- a narrower species concept, which was prompted by line inventory for future work assessing impacts of the closer scrutiny of morphological variation, mating trials, currently ongoing changes in the Arctic and Antarctic and DNA sequence data. Moreover, microsatellite data marine environment. In both cases, diving surveys and indicate that populations of a single species are fragmen- collections of macroscopic algae were complemented tary on a regional scale, giving ample opportunities for by applying the Germling Emergence Method and ‘ allopatric and peripatric speciation. In the new many DNA barcode sequencing of the live isolates obtained ’ endemics paradigm, it makes sense that particular dia- from substratum samples. We present a baseline sea- tom species might at times be transported outside their weed species checklist for northern Baffin Island in native range through human agency and disrupt the the Arctic and southern Adelaide Island/Northern natural functioning of the communities to which they Marguerite Bay in the Antarctic, respectively, report- are introduced (just as has happened innumerable times ing numerous new records of seaweed taxa and asso- with macroscopic animals, plants and seaweeds). There ciated pathogens. The paper also discusses have been several claims that this has indeed occurred. implications for establishing baseline inventories and Thus, for example, Coscinodiscus wailesii is supposed managing safe and scientifically productive diving to have been introduced to European waters c. 1970 operations in remote polar locations. (perhaps with oyster spat or perhaps in ship ballast water) and to be ‘invasive’. The criteria for assessing such claims have not been clearly defined and will be discussed (e.g. good taxonomy consistently applied, 10OR.12 appropriate search strategy, etc) with reference to TEMPORAL AND SPATIAL POPULATION selected planktonic and benthic diatom species. My STRUCTURE AND GENETIC DIVERSITY conclusion is that there is no convincing evidence for DURING A BLOOM OF THE MARINE introduction of any marine planktonic diatom (e.g. old DIATOM PSEUDO-NITZSCHIA collections show C. wailesii was already in the UK in the MULTISTRIATA early 20th century). Conversely, application of the same criteria suggests that a benthic species, Diademoides Maria Valeria Ruggiero (mariavaleria.ruggiero@szn. luxuriosa, has been introduced to the UK from the it), Mariano Santoro ([email protected]), Maria Pacific. This single example indicates that introductions Immacolata Ferrante ([email protected]), have probably been frequent and will likely increase, but Daniele Iudicone ([email protected]), Wiebe in practice most will be undetected. HCF Kooistra ([email protected]), Domenico D’Alelio ([email protected]), Gabriele Procaccini (gab [email protected]) and Marina Montresor (mar [email protected]) 10OR.11 EXPLORATION OF ARCTIC AND Integrative Marine Ecology, Stazione Zoologica ANTARCTIC SEAWEED BIODIVERSITY IN Anton Dohrn, Naples 80121, Italy THE CONTEXT OF POLAR CLIMATE CHANGE Addressing the question of the origin and maintenance of genetic diversity and structure in phytoplanktonic Frithjof C Küpper ([email protected]) species is of fundamental importance to understand the population dynamics of these organisms, their Oceanlab & School of Biological Sciences, University capability to face and adapt to environmental changes of Aberdeen, Newburgh AB41 6AA, United Kingdom and the possible mechanisms of speciation. We Keynote and Oral Papers 92 assessed the population genetic structure of the toxic nM). Samples for Whole Transcriptome Shotgun pennate diatom Pseudo-nitzschia multistriata in the Sequencing (WTSS), concentration of intracellular Gulf of Naples (Tyrrhenian Sea) on a temporal and ATP, particulate organic carbon (POC) and nitrogen spatial scale, with the aim of clarifying the population (PON), and pigments were collected. Besides, photo- dynamics behind patterns of genetic diversity. For the physiological parameters were determined, using a temporal survey, about 500 strains were isolated at the Fast Repetition Rate Fluorometer (FRRF), in dark Long Term Ecological Research station MareChiara, acclimated samples as well as under increasing levels with weekly sampling during the bloom period in of photosynthetic active radiation (PAR). Significant summer-autumn 2013. For the spatial survey, about gradual decrease of the photosynthetic efficiency 200 strains were isolated from different locations (photosynthetic yield, non-photochemical quenching, along the Tyrrhenian coasts in July 2013. Strains electron transfer rate, etc.), growth rate and ATP cell were genotyped using 27 polymorphic microsatellite quota, was obtained for the different treatments. loci, of which 20 were designed on the P. multistriata Several studies have suggested that the physiological de novo genome sequence. Two main blooms were mechanisms to survive under different levels of Fe recorded: one in August-September and a minor one limitation were different. We also identify a sequential in October. Genotypic diversity was high during the response to severity of Fe limitation at transcriptomic first bloom (G/N = 97.95), but considerably dropped level. At each condition of limitation one assortment at the beginning of the second bloom (G/N = 24.61), of unique genes lead showed specific signatures to Fe which was due to a few strains, one of them largely limitation stress. The combination the physiological dominating the population. However, growth rates of and transcriptomic responses will contribute to a more the ‘dominant’ strain did not differ significantly from complete picture on iron-stress homeostasis in cyano- those of the other strains. Likely, other mechanisms of bacteria. Consequently, also contribute to the better intra-specific competition should be invoked to understanding of the ocean biogeochemistry and the explain this case of clonal selection (e.g. parasite biological carbon pump that regulates our climate. selection or allelochemical interactions). The spatial survey revealed a very high genetic diversity, but weak population structure, suggesting that a single 10OR.14 spatially extended population acts as a source for the inoculum of the bloom. BIOCHEMICAL ADAPTATION OF THE INVASIVE GRACILARIA VERMICULOPHYLLA ALONG A GRADIENT OF TEMPERATURE, FROM PORTUGAL TO NORWAY 10OR.13 Gwladys Surget1 ([email protected]), IRON LIMITATION IN THE 2 Klervi Le Lann ([email protected]), CYANOBACTERIA SYNECHOCOCCUS SP.: 3 Gaspard Delebecq (Gaspard.Delebecq@univ-brest. FROM GENE EXPRESSION TO 4 fr), Nelly Kervarec ([email protected]), PHYSIOLOGICAL RESPONSES 5 Fabienne Le Grand (fabienne.legrand@univ-brest. Sonia Blanco-Ameijeiras1 ([email protected]) fr), Anne Donval3 ([email protected]), and Chistel Hassler2 ([email protected]) Vivian Husa6 ([email protected]), Nathalie Poupart7 ([email protected]) and Valérie 1Marine and Lake Biogeochemistry, University of Stiger-Pouvreau7 ([email protected]) Geneva, Versoix 1290, Switzerland and 2Marine and Lake Biogeochemistry, University of Geneva, Vesoix 1LEMAR, IUEM - Université de Bretagne 1290, Switzerland Occidentale, Plouzane 29280, France; 2LEMAR, IUEM - Université de Bretagne Occidentale, France In up to 40 % of the ocean the growth of phytoplank- 29280, France; 3LEMAR, IUEM - Université de ton and carbon dioxide fixation is limited by the lack Bretagne Occidentale, Plouzané 29280, France; of iron (Fe). This essential micronutrient is particu- 4RMN-RPE-MS, Université de Bretagne Occidentale, larly important for photosynthetic organisms because Brest 29200, France; 5LEMAR - LIPIDOCEAN, of their high Fe requirements for the photosynthetic IUEM - Université de Bretagne Occidentale, machinery. Cyanobacteria have developed several Plouzané 29280, France; 6Institute of Marine strategies to survive in Fe limited environments. In Research, Bergen 5817, Norfolk Island and 7LEMAR, this study, we characterize the homeostasis of the IUEM - UBO, Plouzané 29280, France marine cyanobacteria Synechococcus sp. PCC 7002 growing in steady-state under three levels of iron Seaweeds represent one of the largest groups of limitation. Cultures were performed in chemically marine aliens in Europe, and constitute between characterized synthetic seawater amended with 20 and 29 % of all invasive marine species. Alien increasing concentrations of Fe (0.6, 2, 20 and 200 species have been shown to be particularly adaptive Keynote and Oral Papers 93 through phenotypic changes. Moreover, to colonize vermiculophylla across its Atlantic distribution, their novel environment, invasive species have to from Portugal to Norway. For this purpose, G. adapt their defense against epiphytes and grazers, vermiculophylla was collected at three sites in by e.g. production of chemical cues. Abiotic factors each of three countries (Portugal, France and regulating primary production, such as latitudinal Norway). The total lipid and fatty acid composition variation in temperature, can also influence the bio- weremeasured by HP-TLC and gas chromatography chemical adaptation in alien seaweeds. These and pigments were quantified using HPLC and aspects have not been studied previously in spectrophotometry. Moreover, chemical footprinting Gracilaria vermiculophylla. This species was analyses were obtained by HRMAS NMR. Our recently observed along the European coasts, and results are discussed in regard to the variability of is able to modify the estuarine habitat it invades, all molecules in G. vermiculophylla along the tempera- along the European Atlantic coasts. In this context, ture gradient. This work was financed with the this study assessed latitudinal variation in macro- support of the EU FP7 ERA-NET Program, Seas- molecules of the invasive red macroalga Gracilaria Era INVASIVES project nr. ANR-12-SEAS-0002 Keynote and Oral Papers 94

11. Genetic engineering in algae: novel molecular tools and novel model species.

11KN.1 @sb-roscoff.fr) and Susana M Coelho1 (coelho@sb- roscoff.fr) DIATOMS AS MODEL SYSTEM FOR ALGAE WITH SECONDARY PLASTIDS 1UMR8227, Station Biologique de Roscoff, Roscoff Peter G Kroth ([email protected]) 29682, France and 2UMR8227, “Station Biologique de Roscoff, Roscoff 29682, France Department of Biology, University of Konstanz, Konstanz 78457, Germany The brown algae are considered to be the most devel- opmentally complex group of organisms after animals In the recent years research on molecular aspects of and land plants. These seaweeds include, for example, microalgae showed a breath-taking development. some of the largest organisms on the plant, the giant While in the beginning, the green alga Chlamy kelps, which can reach lengths of more than 50 metres. domonas reinhardtii was the only model system that Brown algae are therefore clearly of interest for under- allowed genetic approaches to study cellular functional- standing the mechanisms underlying developmental ities, other non-chlorophyte model systems are catching processes but, at present, very little is known about the up. Here diatoms are especially noteworthy as they not molecular basis of development in these organisms. only were the first non-green microalgae for which a About ten years ago we proposed the filamentous useful genetic transformation system had been devel- brown alga Ectocarpus as a general model organism oped, they also are excellent model systems for a better for the brown algae. Ectocarpus was selected specifi- understanding of cellular processes involved in second- cally because of the potential of this alga for the applica- ary endosymbiosis, silica cell wall formation as well as tion of genetic and genomic approaches. A broad range the physiological reasons for the profound ecological of resources have now been developed for this organism, importance of diatoms. Besides the availability of anno- including a complete, well-annotated genome sequence, tated genome sequences of a number of diatoms, several extensive mRNA and small RNA transcriptomic data, a approaches regarding reverse genetics have been devel- genetic map and other genetic tools. These resources are oped recently including RNAi and genome editing using currently employed to identify and characterise key TALEN approaches. This is extremely important regulatory loci associated with several developmental because (i) diatoms are diplonts, thus random mutations processes including, for example, the control of life in single alleles may not lead to phenotypes, and (ii) cycle progression and sex-determination. Here we will most diatoms do not show sexual reproduction in the review some of the genetic and genomic approaches that lab, thus the availability of using sexual crosses to obtain are used to identify these loci including classical posi- homozygous mutants is very limited. In this presenta- tional cloning approaches using the genetic map, NGS- tion, the current status of molecular genetic approaches based cloning methods such as the SHOREmap for diatoms will be described. approach, genome resequencing and genome-wide comparative methods.

11KN.2 DEVELOPMENT OF FORWARD GENETIC 11KN.3 AND GENOMIC APPROACHES TO IDENTIFY ALGAL CHLOROPLAST ENGINEERING: KEY REGULATORY GENES IN THE BROWN NEW TOOLS, TECHNOLOGIES AND ALGAE APPLICATIONS 1 1 J Mark Cock ([email protected]), Alok Arun Saul Purton ([email protected]) ([email protected]), Delphine Scornet1 (scor [email protected]), Akira F Peters1 (peters@gmail. Structural & Molecular Biology, UCL, London WC1E com), Olivier Godfroy1 ([email protected]), 6BT, United Kingdom Alexandre Cormier1 ([email protected]), Nicolas Macaisne1 ([email protected]), Toshiki Uji2 The last few years have seen an ever-increasing ([email protected]), Sophia Ahmed1 (ahmed interest in the exploitation of microalgae as Keynote and Oral Papers 95 recombinant platforms for the synthesis of novel and thus have a profound effect on the global bio-products. These could be biofuel molecules, biogeochemical cycles. Many coccolithophores speciality enzymes, nutraceuticals or therapeutic synthesise calcite scales in a specialised intracellu- proteins such as antibodies, hormones and vac- lar compartment called the coccolith vesicle, then cines. This exploitation requires the development secrete the finished coccolith onto the cell surface. of new genetic engineering technologies for spe- Coccoliths are morphologically complex, and their cies suited for intensive commercial cultivation in architecture is genetically encoded. An understand- bioreactor systems. In particular, there is a need ing of the mechanisms underlying the fine control for routine methods for the genetic manipulation of calcite crystal shape in coccolithophores would of the chloroplast genome (plastome) for two have relevance for the design of advanced materi- reasons: firstly, the chloroplast genetic system is als. Our knowledge of the molecular mechanisms well-suited to the targeted insertion into the gen- of calcification in coccolithophores is extremely ome and high-level expression of foreign genes, limited. To further our understanding of this pro- secondly, the organelle is the site of numerous cess and to maximise the biotechnological poten- biosynthetic pathways and therefore represents tial of coccolithophores, the development of tools the obvious ‘chassis’ onwhichtoboltnewmeta- for their genetic manipulation is highly desirable. bolic pathways that divert the carbon fixed by We have focused on the development of genetic photosynthesis into novel hydrocarbons, pig- transformation systems for the abundant, bloom ments, etc. I will present recent progress in my forming species Emiliania huxleyi and the coastal group on the development of advanced tools for species Pleurochrysis carterae. We will discuss the the engineering of the Chlamydomonas plastome, particular challenges of working with coccolitho- and give examples of possible applications. phores, from limited antibiotic susceptibility, to the Specifically, we have developed new expression complexities of their life cycles as well as the vectors, a recipient host and an easy DNA deliv- challenges of delivering DNA into the cell and ery method that simplifies the creation of homo- achieving integration into the genome. We will plasmic transgenic lines without the use of reporttheprogresswehavemadeindeveloping antibiotic-resistance markers. We have developed selectable marker cassettes under the control of a negative selectable marker that allows, inter native regulatory sequences and in developing alia, the investigation of nuclear trans-acting fac- selection systems based on antibiotic resistance tors that regulate the mRNA stability/translation and on the complementation of thiamine auxotro- of endogenous chloroplast genes, and thus the phy. Finally, we will present our progress in the expression of transgenes fused to the UTR ele- establishment of DNA delivery systems, and our ments from these genes. We also have develop a pipeline for the analysis of putative transformants. simple codon-reassignment method to address both the problem of unwanted transgene expression in E. coli when creating transformation con- 11OR.2 structs, and the need for transgene containment within the polyploid chloroplast. Current applica- BIOTECHNOLOGICAL OPTIMIZATION OF tions include the production of anti-bacterial pro- LIGHT USE EFFICIENCY IN NANNOCHLOROPSIS teins for several major bacterium pathogens, and CULTURES the introduction of enzymes for the synthesis of Tomas Morosinotto ([email protected]) novel terpenoids. Biology Department, Università di Padova, Padova 35121, Italy 11OR.1 Microalgae have reemerged as potential next-generation THE DEVELOPMENT OF GENETIC TOOLS feedstock for biofuels and they are considered very FOR COCCOLITHOPHORES promising on the long term, thanks to their high produc- Alastair W Skeffington (skeffington@mpimp-golm. tivity per area and ability to grow on marginal land mpg.de) and André Scheffel (scheffel@mpimp-golm. without competing with food crops. Solar radiation pro- mpg.de) vides the energy supporting algae growth and lipids production and the available radiation must be exploited Plant Organelle Biology and Biotechnology, Max- with the highest possible efficiency to optimize produc- Planck Institute of Molecular Plant Physiology, tivity and make their cultivation on a large scale eco- Potsdam-Golm 14476, Germany nomically competitive. Investigation of the bases affecting light use efficiency is thus seminal to improve Coccolithophores are the most prolific producers lipid/biomass productivity of algae industrial cultivation. of calcium carbonate in the marine environment One major point to be considered is that algae in Keynote and Oral Papers 96 photobioreactor/ponds are growing in an artificial envir- bining a fast growth rate with a high accumulation of onment and experience substantially different conditions lipids. A combination of genomic, transcriptomic and with respect to the ones where these organisms evolved. metabolomics analyses were also employed to describe In order to optimize algae cultivation is thus seminal to in detail cells response to different conditions, with the understand how this artificial environment affects pro- aim of identifying limiting steps for biomass and lipids ductivity. This problem was faced by analyzing the productivity in this alga. All information obtained is influence of key parameters like light dynamics, nutri- currently exploited to drive efforts for Nannochloropsis ents availability, CO2 supply to algae productivity in genetic modification. Mutants with altered regulation of batch/ continuous cultures, focusing on the seawater photosynthesis has been isolated and showed improved microalgae Nannochloropsis gaditana, a species com- productivity in lab scale photobioreactors. Keynote and Oral Papers 97

12. Ecology, physiology and taxonomy of freshwater phytoplankton

12KN.1 CO2 fixation in cyanobacteria may be facilitated as PHYSICAL AND BIOLOGICAL DISPERSAL they possess a RubisCO (Ribulose-1,5-bisphosphate fi BARRIERS IN BLOOM-FORMING Carboxylase/Oxygenase) with among the lowest af - fi MICROALGAE nities for CO2. To compensate for this low af nity, they have developed carbon concentrating mechan- Karin Rengefors ([email protected]) isms (CCMs), which are cellular mechanisms to enhance CO2 concentrations in the vicinity of Department of Biology, Lund University, Lund 22362, RubisCO. Various freshwater cyanobacteria species Sweden are toxic and can proliferate under eutrophic conditions, forming dense harmful blooms. Among the Many freshwater and marine phytoplankton are wide- most common toxins produced are microcystins. spread, and it is therefore assumed, that they disperse Consisting of seven amino acids, these are nitrogen- easily and frequently. However, many recent studies rich compounds of which many variants exist with have shown both high genetic diversity and biogeogra- distinct toxicities. The development of a cyanobacter- phical patterns. My approach to address this issue is to ial bloom results in the depletion of resources, includ- investigate genetic diversity and dispersal at the popu- fi ing CO2, light and nitrogen. During bloom lation rather than species level. Speci cally, I will pre- development, cells thus experience large shifts in sent the results from a collaborative project focused on resource availabilities with possible consequences the roles of physical and biological dispersal barriers in for CO2 fixation, carbon:nutrient stoichiometry and freshwater as well as marine phytoplankton. To address toxin synthesis. In this talk, I will explore the extent this topic we have used a population genetic approach to which elevated pCO2 may alter both carbon and using AFLP, microsatellite, and recently RADtag high nitrogen assimilation, and how this may affect the throughput sequencing technology, combined with toxicity of freshwater cyanobacteria. laboratory experimental studies. By exploring the population genetic structure, we could assess dispersal and diversification among populations. We specifically investigated a freshwater raphidophyte (Gonyostomum 12OR.1 semen), which has recently expanded its habitat range, INORGANIC CARBON ACQUISITION and find that the populations are already genetically CHARACTERISTICS OF AUSTRALIAN differentiated. Moreover, we present results showing FRESHWATER MICROALGAE FROM A that hydrological connectivity does not matter on the SUBTROPICAL RESERVOIR local scale, while we have genetic isolation with distance. In a marine diatom, on the other hand, large- Thomas Lines1 ([email protected]), John scale ocean currents and environmental factors shape Beardall1 ([email protected]) and Anusuya the populations. We have also explored the role of Willis2 (anusuya.willis@griffith.edu.au) biological barriers, such as priority effects and local 1 adaptation, in causing population differentiation in School of Biological Sciences, Monash University, 2 phytoplankton. Melbourne 3800, Australia and Australian Rivers Institute, Griffith University, Brisbane 4111, Australia

12KN.2 Most microalgae from marine and freshwater environments possess CO2 concentrating mechan- BLUE-GREENS OFF BALANCE? isms (CCMs) that render them relatively unaf- Dedmer B Van de Waal ([email protected]) fected by CO2 levels in the environment. Nonetheless, different species express CCMs to Aquatic Ecology, Netherlands Institute of Ecology, varying extents and thus future rises in atmo- Wageningen 6700 AB, Netherlands spheric CO2 could potentially influence species composition in algal populations. In an attempt to Elevated pCO2 may fuel phytoplankton photosynth- understand the potential effects of elevated atmo- esis and thereby promote their growth. Particularly spheric CO2 on algal growth and populations in Keynote and Oral Papers 98 freshwater systems we investigated some of the algae originating from habitats with different pH carbon acquisition characteristics of six strains of values for their Ci acquisition preference by using freshwater phytoplankton from Lake Wivenhoe, pH-drift experiments and determining Ci uptake South East Queensland, Australia. These included parameters at different external pH. We addition- Cyclotella sp. (Bacillariophyceae), Cylindrosper ally studied algae previously adapted to both high mopsis raciborskii (Cyanophyceae), Monorap and low CO2 conditions to examine the influence hidium sp. (Chlorophyceae), Nitzschia sp. of CO2 supply. Our results confirmed a significant (Bacillariophyceae), Staurastrum sp.(Zygnemo influence of external pH on growth due to varying phyceae), and Stichococcus sp. (Chlorophyceae). pH preferences with pH of the natural habitat as We determined rates of gross photosynthesis, well as on Ci acquisition in all four species. Final respiration and the half-saturation rate constants pH values at the end of the pH drifts and Ci/ for light (K0.5, I)andDIC(K0.5, CO2) by oxygen alkalinity quotients varied among algal species electrode and rates of electron transport by chlor- and treatments and therefore led to different effi- fl ophyll uorescence (Walz PhytoPAM). The ability ciencies of Ci uptake and Ci species used. Low of cells for acquisition of CO2 vs bicarbonate was CO2 compensation points for all species implied measured by isotopic disequilibrium and internal that differences among species are linked to the pH, internal carbon pool and the cells’ ability to usage of bicarbonate, which demonstrated that concentrate CO2 was determined directly via the CO2 concentrating mechanisms were present. In fi silicon oil centrifugation technique. Af nities for addition, the acclimation from high to low CO2 CO2 (K0.5, CO2) varied between 0.73 µM for the conditions during the drift revealed interesting dif- diatom Cyclotella,to5.33µMforthedesmid ferences of Ci uptake rates and Ci uptake efficien- Staurastrum. Maximum rates of photosynthesis cies between species. In conclusion, we found that rangedbetween0.55to42.6nmolO2 cell.min- Ci acquisition was highly variable within a single − − 1.10 6 for C. raciborskii and Staurastrum respec- phylogenetic group of green algae and showed that tively. Internal pH varied between 7.66 for there was a connection between Ci acquisition and Stichococcus,to7.97forStaurastrum.Wediscuss ecology. the differences between strains and the consequences for changing populations in a future with elevated atmospheric CO2. 12OR.3 INDEPENDENT COLIMITATION FOR CO2 AND INORGANIC PHOSPHORUS 12OR.2 Elly Spijkerman ([email protected]), ECOLOGY MATTERS: LINKING INORGANIC Francisco de Castro ([email protected]) and CARBON ACQUISITION TO ECOLOGICAL Ursula Gaedke ([email protected]) PREFERENCE IN FOUR SPECIES OF MICROALGAE (CHLOROPHYCEAE) Department of Ecology and Ecosystem Modelling, Sabrina C Lachmann1 ([email protected]), University of Potsdam, Potsdam 14469, Germany Elly Spijkerman1 ([email protected]) and Stephen C Maberly2 ([email protected]) Simultaneous limitation of plant growth by two or more nutrients is increasingly acknowledged as a 1Biochemistry and Biology, University of Potsdam, common phenomenon in nature, but its cellular Potsdam 14469, Germany and 2Centre for Ecology & mechanisms are far from understood. We investi- Hydrology, Lancaster Environment Centre, Bailrigg, gated the uptake kinetics of CO2 and phosphorus Lancaster LA1 4AP, United Kingdom of the algae Chlamydomonas acidophila in response to growth at limiting conditions of CO2 The effect of CO2 supply seems to play a particu- and phosphorus. In addition, we fitted the data to larly important role in algal ecology. Inorganic four different Monod-type models: one assuming carbon (Ci) acquisition strategies are very diverse Liebigs Law of the minimum, one assuming that among microalgae and are influenced by several the affinity for the uptake of one nutrient is not environmental factors such as pH, light and inor- influenced by the supply of the other (independent ganic phosphorus concentration. Because different colimitation) and two where the uptake affinity for species of microalgae vary in their habitat prefer- one nutrient depends on the supply of the other ence, we hypothesized that Ci acquisition depends (dependent colimitation). In addition we asked on the pH of the preferred natural environment whether the physiological response under colimita- (adaptation) and that the efficiency of Ci uptake tion differs from that under single nutrient limita- is affected by CO2 availability (acclimation). tion.We found no negative correlation between the Therefore, we analysed four species of green affinities for uptake of the two nutrients, thereby Keynote and Oral Papers 99 rejecting a dependent colimitation. Kinetic data between strains. The results suggest that the different were supported by a better model fitassuming strains are suited to different light habitats. Thus, the independent uptake of colimiting nutrients than temporal and/or spatial changes in the light environ- when assuming Liebigs Law of the minimum or mental conditions may affect bloom toxicity by helping a dependent colimitation. Results show that cell to regulate the dynamics of changing dominance and nutrient homeostasis regulated nutrient acquisition succession patterns of toxic and nontoxic strains. which resulted in a trade-off in the maximum uptake rates of CO2 and phosphorus, possibly driven by space limitation on the cell membrane for 12OR.5 porters for the different nutrients. Hence, the response to colimitation deviated from that to a USING CORRESPONDENCE ANALYSIS TO single nutrient limitation (Spijkerman et al. 2011 DETERMINE RELATIONSHIPS BETWEEN PLoS One 6 (12):e28219). ABIOTIC FACTORS AND THE DENSITY OF DESMODESMUS SPECIES IN POLISH LAKES Elliot Shubert1 ([email protected]), Elżbieta 12OR.4 Wilk-Woźniak2 ([email protected]), Sławomir Ligęza3 ([email protected]) and Wojciech GROWTH AND PHYSIOLOGY OF TOXIC 2 Mróz ([email protected]) AND NON-TOXIC CYANOBACTERIA IN RELATION TO LIGHT INTENSITY 1Faculty of Science and Technology, University of Md Ashraful Islam ([email protected]) Westminster, London W1M 8JS, United Kingdom; and John Beardall ([email protected]) 2Department of Freshwater Biology, Institute of Nature Conservation, Kraków PL-31-120, Poland Biology, Monash University, Clayton 3800, Australia and 3Engineering and Environment Management, Institute of Soil Science, Lublin PL-20-950, Poland Cyanobacteria are major bloom-forming organisms in freshwater ecosystems all over the world. In addition to Two oxbow lakes (R1 and R2) and one artificial dam high concentrations of nitrogen, phosphorus and car- reservoir (R3) were used to evaluate the quantity and bon, light is the most important parameter for algal diversity range of Desmodesmus species occurring growth. Different strains within the same species may during four seasons of one-year. Water samples were respond differently in terms of growth and physiology quantified for Desmodesmus species and identified depending on the light climate. To evaluate the growth using the Light Microscope (LM) and Scanning and physiological parameters of both toxic and non- Electron Microscope (SEM). The following water toxic strains of Microcystis aeruginosa and Anabaena analyses were conducted: “pH, EC, DO, K, Ca, Mg, 2 circinalis, strains were grown at a range of light inten- TN, NH4-N, NO3-N, TP, SO4 , Fe and Mn. We used sities (10, 25, 50, 100, 150 and 200 µmol photons Correspondence Analysis (CA) analysis to determine m−2s−1) and their photosynthetic characteristics deter- abiotic factors that influenced the density of mined. The study revealed that the toxic strains of both Desmodesmus species in the three aquatic ecosystems. species (for M. aeruginosa CS558 and A. circinalis Not surprisingly, different Desmodesmus species CS537 & CS541) require a higher light intensity to inhabited each water body and exhibited different saturate growth (µ) compared to the non-toxic strains densities of growth, contributing 77% of the total (M. aeruginosa CS338 and A. circinalis CS534). density in R1, 22% in R2 and only 1% in R3. Strains maintained at their growth saturating light Summer and autumn were the seasons when intensities were then characterised in terms of their Desmodesmus showed the highest density in the shal- basic physiology (light harvesting efficiency α, light low and polimictic oxbow lakes (R1 and R2). In the saturation intensity for photosynthesis Ik,maximum deep and dimictic reservoir (R3), the highest density quantum yield Fv/Fm, relative electron transport rate of Desmodesmus was during autumn. Combining all rETRmax). Light-saturated rates of photosynthetic oxy- data into one data-set, four groups were identified. gen evolution (Pmax) and dark respiration (Rd)were Group 1 (D. armatus, D. quadricauda and D. spinosus measures by a Clark type O2 electrode while α,Ik,Fv/ were closely related to conductivity (EC), Ptot (total Fm and rETRmax were determined by PAM chlorophyll phosphorus), chlorides (Cl), phosphates (PO4) and fluorescence (Walz PhytoPAM). Both Rd and Pmax Cu. Group 2 (D. opoliensis and D. subspicatus) were showed significant differences between strains with related to Zn, K, water temp, Fe, Mg, SO4, suspension those strains requiring higher saturating light intensity and Mn. Group 3 (D. abundans) related to ammonia for growth (M. aeruginosa CS558 and A. circinalis (NH4). Group 4 (D. intermedius) related to nitrates CS537 & CS541) differing significantly from the (NO3). These results indicated that each species has other strains. Other photosynthetic parameters such as specific nutrient requirements (singly or in combina- α,Ik,Fv/Fm and rETRmax did not vary significantly tion) that affect their density in the water column. Keynote and Oral Papers 100

Further research will examine the CA of individual Spain and 4Institute of Microbiology, Academy of lakes and the response of Desmodesmus species to Sciences of the Czech Republic (C.A.S.), Prague 142 speciﬁc nutrient conditions in culture. 20, Czech Republic

The rare earth elements (REEs = scandium, yttrium, 12OR.6 lanthanum and 14 lanthanides) currently are in great commercial demand due to rapid technological pro- SEASONALITY OF INTRA-SPECIFIC CELL gress. In parallel, they are also increasing as environ- SIZE IN THE PHYTOPLANKTON OF LAKE mental pollutants. Our main objective was to study the KINNERET little known effect of REEs on microalgae. A cyano- Tamar Zohary1 ([email protected]), Miki bacterium and three different microalgae were grown Shlichter1 ([email protected]) and Luigi Naselli- under conditions of exposure to REEs. Toxicity Flores2 ([email protected]) occurred at high concentrations, but at low concentrations, they stimulated microalgal growth rate. We also 1Kinneret Limnological Laboratory, Israel observed changes in the total amount and specific Oceanographic & Limnological Research, Migdal composition of pigments and lipids. However, the 14950, Israel and 2Department of Biological, specific growth promoting mechanisms are still Chemical and Pharmaceutical Sciences, University of unknown. In further experiments, we investigated Palermo, Palermo I-90123, Italy whether REEs can replace essential metals in their functions and explain growth stimulation in A distinct pattern of seasonal fluctuations in intra- Desmodesmus quadricauda (Chlorophyta). We specific cell size and/or colony size was observed in observed that to some extent the REEs could replace a large number of phytoplankton species from Lake calcium but not manganese (where detrimental effects Kinneret, Israel. The same species showed larger cell increased). From our results we deduce that despite size or colony size in late winter and smaller size in their relatively low toxicity, it is still difficult to predict late summer, with intermediate sizes in the interim the impact of REEs in the environment. Supported by periods. This phenomenon was exhibited by species the Long-term Research Development Project no. of chlorophytes, dinoflagellates and cyanobacteria RVO 61388971 of the Academy of Sciences of the that were abundant enough to be sampled (fortnightly) Czech Republic. By the National Program of and measured throughout the year. The annual pattern Sustainability I, ID:LO1416. We thank also the of fluctuations in size repeated itself over 8 consecu- Grant GACR14-00227S of the Czech Science tive years (2004–2012). The size fluctuations were Foundation (GACR) and the Junta de Andalucía y independent of the temporal changes observed in cell Ministerio de Educación de España (FPU grant abundance of each species. Rather, peak sizes coin- AP2009-2770). cided with lowest water temperature and highest nutrient availability, minimum sizes with highest water temperature and lowest nutrient availability. These 12OR.8 observations fit well with current ecological theory on organism size, where larger organisms occur in SILICA-SCALED CHRYSOPHYTES ON THE colder climates and the reverse in warmer climates. SALINITY GRADIENT Yvonne Němcová ([email protected]), Martin Pusztai ([email protected]), Magda Skaloudova 12OR.7 ([email protected]) and Jiří Neustupa ([email protected]) ON THE EFFECT OF RARE EARTH ELEMENTS ON MICROALGAE: Department of Botany, Charles University in Prague, POLLUTANTS AND GROWTH STIMULANTS Prague 12801, Czech Republic Franz Goecke1 ([email protected]), Celia G Jerez2 ([email protected]), Félix L Figueroa3 (felix_lope Silica-scaled chrysophytes (Stramenopiles, Ochro [email protected]), TomášŘezanka4 ([email protected]. phyta) are represented predominantly by freshwater cz) and Milada Vítová1 ([email protected]) flagellates. The high conductivity group of species was defined by Peter Siver and a diverse silica-scaled 1Institute of Microbiology, Academy of Sciences of the chrysophyte assemblage, comprising more than 50 Czech Republic (C.A.S.), Třeboň 379 81, Czech taxa, was previously revealed from brackish waters Republic; 2Departmento de Ecología, Facultad de of the Pojo Bay, the Gulf of Finland, Baltic Sea. Ciencias, Universidad de Málaga, Málaga 29071, However, it was supposed that part of the community Spain; 3Departamento de Ecología, Facultad de was delivered to the area by freshwater river inputs. To Ciencias, Universidad de Málaga, Málaga 29071, investigate the effect of salinity on species diversity Keynote and Oral Papers 101 and community structure, we sampled the lakes in the ing in less saline localities. Species that were abundant close proximity to the shoreline (up to 5 km) and deep in low saline sites also were abundant in sites with almost closed bays (salinity values of 0.01-2.66 prac- salinity over 0.2 psu. Twelve recorded silica-scaled tical salinity units) of the Gulf of Bothnia, Baltic Sea. chrysophytes (out of 83 taxa) significantly preferred We excluded exposed seashore sites to minimalize low saline waters. On the contrary, occurrence of six river flow impact. Species determination was based species correlated positively with salinity (e.g. on scale morphology, which was investigated with a Mallomonas tonsurata and M. alpina). In contrast to transmission electron microscope. Salinity was the diatoms where a gradually change of species strongest predictor of diversity; the Shannon index composition on salinity gradient was recorded (num- significantly declined with increasing salinity. ber of freshwater species decreased and number of Community structure of silica-scaled chrysophytes brackish to marine species increased), silica-scaled was influenced most strongly by pH. However, pH chrysophytes represent a typical freshwater group and salinity were highly correlated. We determined where the number of species able to adjust to that a pool of species inhabiting the sites with salinity environmental conditions declined with increasing over 0.2 psu represented a subset of the species thriv- salinity. Keynote and Oral Papers 102

13. Omics and genetic resources towards algal domestication

13KN.1 mucilage. Once settled, neutral spores exhibit amoe- boid movement prior to final attachment. THE PORPHYRA UMBILICALIS GENOME: Differentiating neutral spores show increased tran- STUDIES ON THE PATH FROM GENOME TO scriptional activity for some genes associated with GROCERY STORE photosynthesis. Interestingly, nearly 3,000 transcript Nicolas Blouin1 ([email protected]), Simon Prochnik2 assemblies showed upregulation only in the marginal ([email protected]), Elisabeth Gantt3 (egant area, including transcripts associated with the cytos- [email protected]), Sarah Redmond4 (sarah.redmond@ keleton, vesicular transport, and extracellular adhe- maine.edu), Erika Lindquist5 (EALindquist@lbl. sion. Electron micrographs show increased vesicular gov), Arthur Grossman6 ([email protected]), activity in marginal spores. These results suggest that John W Stiller7 ([email protected]), Jeremy Schmutz2 mature neutral spores contain a transcriptome that ([email protected]), Jerry Jenkins2 (jjenkins@hud supports spore release, movement to a suitable micro- sonalpha.org), Kerrie Barry2 ([email protected]) habitat, and substratum attachment. P.um.1 was grown and Susan H Brawley8 ([email protected]) to harvestable size (10-12 cm blade length; 139 (+/- 40) g wet wt/m kuralon line) in Frenchman’s Bay 1Department of Biological Sciences, University of (Maine, USA) from such neutral spores. Continued Rhode Island, Kingston 02881, United States; 2Joint analysis of P.um.1 by our JGI/NSF RCN annotation Genome Institute, U.S. Department of Energy, Walnut team should lead to new insights related to its meta- Creek 94598, United States; 3Department of Cell bolism that will influence product development and Biology & Molecular Genetics, University of enhance our understanding of stress tolerance of this Maryland, College Park 20740, United States; species, its evolution, and its metagenome. 4Maine Sea Grant college Program, Orono 04469, United States; 5Joint Genome Institute, U.S. Department of Energy, Walnut creek 94598, United 13KN.2 States; 6Department of Plant Biology, Carnegie Institution for Science, Stanford 94305, United States; OMICS IN DECIPHERING THE 7Department of Biology, East Carolina University, EVOLUTIONARY WARFARE BETWEEN PYROPIA Greenville 27858, United States and 8School of AND ITS PATHOGENS Marine Sciences, University of Maine, Orono 04469, Gwang Hoon Kim ([email protected]) United States Biology, Kongju Natoional University, Kongju An asexual isolate of Porphyra umbilicalis (P.um.1) 314-701, South Korea that directly recycles the commercially valuable Porphyra blade has been sequenced at the Joint As with land crops, algal cultivation beds are suffering Genome Institute (JGI). The assembled genome is from various diseases, ranging from spectacular out- ~96 Mbp (without repeats), with 20,762 predicted breaks in natural populations, down to significant genes in a draft assembly. Genic regions average losses in multibillion dollar crops such as Pyropia 67% GC. The simple life history found in P.um.1 spp. Recent estimation on economic loss caused by occurs throughout the northwestern Atlantic, and pro- Pyropia diseases showed that sea farmers in Korea vides a model for understanding spore differentiation lose about 10-15 million dollar because of algal dis- and maturation in a multicellular red alga. To study ease every year, mostly due to fungal disease caused gene expression associated with production of neutral by the oomycete pathogens, Olpidiopsis pyropiae and spores, we assembled 67k transcripts from RNA-Seq Pythium porphyrae. The recent development of inten- analysis on three regions of blades: the central vege- sive and dense mariculture practices have made some tative area (abutting basal rhizoids), the sub-marginal new diseases spread much easier than before. area of the blade where mitotic divisions produce Comparative transcriptomic study showed that the differentiating neutral spores, and the marginal area causative agent of green spot disease is a noble RNA where there is a cm-deep region of mature neutral virus, which could infect broad spectrum of Pyropia spores. In nature, re-wetting of P. umbilicalis blades species. Host plants intensively use RNA binding by the incoming tide stimulates release of large quan- proteins for defense against viral infections in nature. tities of naked neutral spores and accompanying We isolated 6 RNA-binding proteins which are highly Keynote and Oral Papers 103 upregulated during infection process. Metagenomic 13KN.4 studies on Pyropia and its epiphytic bacteria showed THE DOMESTICATION PROCESS IN THE that some epiphytic bacteria are involved in fungal RED ALGA GRACILARIA CHILENSIS: RAPID infection to Pyropia. An elicitor released from epiphy- CHANGES OBSERVED AFTER ONLY 30 tic bacteria facilitated zoosporogenesis of Pythium YEARS OF INTENSIVE FARMING porphyrae. The evolutionary warfare between Pyropia and its pathogens left many traces in the Marie-Laure Guillemin (marielaure.guillemin@ genomes of both sides. Therefore, proteomic and tran- gmail.com) scriptomic studies on Pyropia and its pathogens are crucial to develop a disease-resistant Pyropia strain. Instituto de Ciencias Ambientales y Evolutivas, The pros and cons of mutation breeding of disease- Facultad de Ciencias, Universidad Austral de Chile, resistant Pyropia strain will be presented. Valdivia Casilla 567, Chile and UMI 3614 Evolutionary Biology and Ecology of Algae, Sorbonne Universités UPMC Univ. Paris 06, Roscoff 13KN.2 29688, Chile GENOME STRUCTURE Interestingly, even if the domestication of Gracilaria CHARACTERIZATION OF SACCHARINA JAPONICA chilensis has begun recently, archaeological evidence suggests that this species was used for food and/or Duan Delin ([email protected]) medicine since the first establishment of human populations along the South East Pacific 14,600 years ago. Experimental Marine Biology Lab, Institute of Nowadays, this species is one of the main algal Oceanology, CAS, Qingdao 266071, China resources in Chile, which is cultivated for agar production. In the 90’s, over-harvesting resulted in the Saccharina japonica was regarded as important to the collapse of natural stands and stimulated the imple- edible human food, alginate production and marine mentation of farms maintained by fragmentation. A eco-systematic contribution. So far, more than 10 first population genetic study, comparing farmed and cultivars have been applied in the production in wild populations Chilean populations of G. chilensis, China, but many genomic backgrounds of biological concluded that farming practices had significantly processes and genomic architecture are not under- modified important life history traits in farms. A com- stood very well. The genome sequence for the wild plementary study, based on temporal variation of S. japonica strain was conducted with next-generation genetic diversity in these two types of populations, sequencing. Genomic DNA libraries were constructed shows that a mixture of haploids and diploids are for the subsequent sequenced, which generated always encountered in natural populations that show approximately 91-fold sequencing reads, and 490 all the signs of recurring events of recombination. By Mb of the assembled genome size. The gene predic- contrast, most farms are composed only of diploids, tion showed that there are a presumed 31,358 genes in generally non-mature, and present genetic variability S. japonica genome. Re-sequencing analysis for the typical of their clonal reproduction system. New common cultivars and some wild strains were both experiments in laboratory-controlled conditions have conducted and compared. The long introns single allowed us to hypothesized that ecological differences copy genes were analyzed, and the repetitive between phases and short term reproductive cost are sequences of the introns were associated with long possible trigger of the life cycle changes in farms and repetitive sequences, the correlation between gene that involuntary selection could operate during the intron length and gene expression level were con- ongoing first step of the domestication process. ducted with the expressed genes. The genome Genome scan approaches are being developed in sequence data useful to our understanding the meta- order to trace the domestication history of this species bolic pathways, genetic adaptation and domestication and to survey the changes in spatial and temporal and the good-quantitative varieties formation to the genetic structure of wild and cultivated populations kelp. in Chile. Keynote and Oral Papers 104

14. The fate of our marine forests in a changing ocean

14KN.1 14KN.2 THE STRUCTURE AND FUNCTIONING OF STUDYING BIODIVERSITY BY AN KELP FOREST ECOSYSTEMS UNDER RAPID INTEGRATIVE APPROACH OF POPULATION ENVIRONMENTAL CHANGE GENETICS AND COMMUNITY ECOLOGY: A WAY TO BETTER PREDICT THE FATE OF Dan A Smale ([email protected]) OUR MARINE FORESTS IN A CHANGING Ecosystems, Marine Biological Association of the OCEAN? United Kingdom, Plymouth PL1 2PB, United Kingdom Marine Robuchon ([email protected])

Kelp forests dominate shallow rocky habitats Institut de Systématique, Evolution, Biodiversité, across much of the world’s temperate coastline. Muséum national d’histoire naturelle, Paris 75231, As foundation species, kelps support high levels France of primary productivity, magnified secondary productivity, and provide habitat for a highly diverse Species diversity and genetic diversity have traditionally associated assemblage. However, the abundances remained the exclusive domains of community ecology and distributions of habitat-forming kelps are and population genetics, respectively, despite repeated responding to global environmental change stres- recognition of close parallels between these levels of sors, including ocean warming, extreme climatic biodiversity the literature. Species diversity within com- events and the spread on non-native species. munities and genetic diversity within populations are Here, I provide an overview of reported kelp hypothesised to co-vary because of locality characteris- forest loss from around the world, with particular tics that influence the two levels of diversity via parallel focus on climate-mediated changes in ecosystem processes (drift, selection and migration) or because of structure. Further attention is focussed on the direct effects of one level of diversity on the other. northeast Atlantic region, where alterations in Corroborating these hypotheses, several studies on dif- kelp forest structure have been recently reported ferent taxa from various geographic zones have revealed and significant shifts have been predicted. In the correlated patterns of species and genetic diversity southwest UK, for example, the abundance of the (mostly positive correlations), suggesting that the ‘warm’ water kelp Laminaria ochroleuca has SGDC (species genetic diversity correlation) might be increased significantly in recent decades, as has a general pattern. In this work, we tested for spatial the distribution of the invasive kelp Undaria pin- SGDC patterns in kelp forests along the Brittany coast- natifida. Conversely, the abundances of several line (France) by conducting a multi-level biodiversity northerly-distributed species (e.g. Laminaria digi- sampling in 20 localities: in each one, we sampled tata and Alaria esculenta) are expected to specimens belonging to the two dominant kelp species decrease under climate change scenarios. The Laminaria digitata (Hudson) J.V. Lamouroux and wider implications of shifts in habitat-forming Laminaria hyperborea (Gunnerus) Foslie as well as kelp species are poorly understood. Here, I sum- macroalgal communities living underneath the canopy marise recent research on the likely impacts of formed by these two species. Genetic diversity for these shifts in kelp forest structure on local biodiversity two kelp species was investigated using microsatellites and primary productivity. Evidence-to-date sug- while the species identity of macroalgal communities’ gests that observed and predicted shifts in kelp specimens was determined based on both morphological species distributions may lead to impoverished and molecular criteria. We tested SGDC for different assemblages in some reef habitats, and altered diversity metrics and at several spatial scales. Our results timings of primary productivity. Greater under- revealed a majority of positive SGDC, suggesting that standing of the (often subtle) community and genetic diversity within kelp populations and species ecosystem-level consequences of shifts/replace- diversity within macroalgal communities are probably ments of habitat-forming species is needed to influenced by parallel processes. However, the signifi- better predict the overall impacts of global envir- cance and strength of the correlation varied among the onmental change. target species, the metrics and the spatial scale Keynote and Oral Papers 105 considered. These findings allow highlighting in which distribution and more robust predictions of species cases i) anthropogenic pressures and/or conservation distribution under climate change. measures have similar effects on species and genetic diversity and ii) one level of diversity can be used as a surrogate for predicting the other. 14OR.1 CHANGES IN KELP FOREST BIOMASS AND 14KN.3 DEPTH DISTRIBUTION AT KONGSFJORDEN COMBINING KNOWLEDGE ON THERMAL (SPITSBERGEN) BETWEEN 1996/98 AND NICHES TO SPECIES DISTRIBUTION 2012-2014 REFLECT ARCTIC WARMING MODELS IN GEOGRAPHICAL Inka Bartsch1 ([email protected]), Martin Paar2 PROJECTIONS IN A CHANGING OCEAN ([email protected]), Stein Fredriksen3 (stein.fre Brezo Martínez ([email protected]) [email protected]) and Christian Wiencke4 (chris [email protected]) Biodiversity and Conservation Unit, Rey Juan Carlos University, Móstoles 28033, Spain 1Biosciences, Alfred-Wegener Institute Helmholtz Center for Polar and Marine Research, Bremerhaven Predictions of species distribution are based on pro- 27570, Germany; 2Wadden Sea Station Sylt, Alfred- jections of the current niches to future climates. The Wegener Institute Helmholtz Center for Polar and most common method, namely Species Distribution Marine Research, List/Sylt 25992, Germany; Model (SDM), relies on projecting the realized niche 3Department of Biosciences, University of Oslo, Oslo of environmental tolerance in the field, measured by 0316, Norway and 4Biosciences, Alfred-Wegener correlating distributional field records with the actual Institute Helmholtz Center for Polar and Marine R, physical conditions. Although a powerful tool, SDM Bremerhaven 27570, Germany do not explores the mechanistic causes of species shifts, making difficult to predict outside the environ- At our Arctic study site at Hansneset, Kongsfjorden, mental gradient were the model was trained. In our Spitsbergen we repeated a quantitative diving study ongoing research line, we are assessing the projections of 1996/98 in 2012-2014 in the shallow rocky sub- of SDMs using thermal thresholds suggested by mor- littoral between depths of 0 and 15 m and detected tality and growth experiments as proxies of the funda- considerable change. There was a 1.7x increase in mental niches of physiological tolerance of foundation overall seaweed biomass, and a 4.7x increase in macroalgae: intertidal fucoids and subtidal kelps in seaweed biomass at shallow depths (2.5 m) between current decline in response to coastal warming in the time periods. The standing stock of the biomass southern Europe. A battery of ecophysiological maximum at 2.5 m comprised 14.4 kg fresh bio- − experiments is being performed by: combining physi- mass m 2, a leaf area index of approx. 10 and a cal stressors for testing additive and interactive very high kelp density, and was composed of three effects, creating thermal gradients for detecting kelp species with a pronounced dominance of thresholds and trigger points, manipulating the mean Laminaria digitata and some Alaria esculenta and intensity and variance of stress to investigate Saccharina latissima. The observed biomass responses to extreme events, and using lineages from increase indicates an increased productivity, which different latitudes for investigating adaptive has been predicted to occur in the Arctic under responses. We use physiological thresholds to produce climate change scenarios. Besides the increase in geographic projections of species’ distributions to overall mean biomass, maximal biomass values of assess projections obtained using SDMs. The predic- perennial seaweed species also increased. At the tions obtained by both approaches are robust in geo- same time a decrease in (1) the lower depth limit graphic areas where the species shows high or low of dominant brown algae by several meter, (2) an dominance. Physiological thresholds tend to over-pre- uplift of the biomass maximum from 5 to 2.5 m as dict the prevalence as they cannot identify absences in well as of the upper depth limit of many seaweed climatic conditions within the range of physiological species and (3) a general decrease of maximal bio- tolerance of the species. SDMs may implicitly capture mass values of annual species became apparent. the mechanisms driving such absences, such as low This complex pattern is probably a consequence of competitive potential under particular environmental contrasting effects induced by Arctic warming, conditions, but this may or may not extrapolate to namely the reduction of fast ice and ice-scouring other geographic areas or times. We present examples in spring as well as a supposedly deteriorating of how integrating correlative and mechanistic underwater irradiance climate by increased sedimen- approaches provides a better understanding of species tation with reduced phases of clear water. Keynote and Oral Papers 106

14OR.2 Chris Yesson1 ([email protected]) and Juliet Brodie2 ([email protected]) LOSS OF THE HABITAT-FORMING CYSTOSEIRA MEDITERRANEA AT ITS 1Institute of Zoology, Zoological Society of London, NORTHERN-LIMIT OF DISTRIBUTION IN London NW14RY, United Kingdom and 2Life THE MEDITERRANEAN SEA Sciences, Natural History Museum, London SW7 Thierry Thibaut ([email protected]), 5BD, United Kingdom Aurélie Blanfuné (aurelie.blanfune-thibaut@ univ-amu.fr), Charles François Boudouresque Major changes are occurring in the abundance of large ([email protected]) brown seaweeds in the northeastern Atlantic. Some and Marc Verlaque ([email protected]) observations of change are anecdotal, although direct evidence of change is increasing. However, one of the Mediterranean Institute of Oceanography, Aix- major impediments in obtaining reliable evidence is Marseille University, Marseille 13009, France the lack of consistent monitoring over periods of time. The reasons for this are multiple, including changes in Large habitat-forming brown algae are suffering a gen- personnel, policy and funding, but also cost and inac- eral decline in temperate seas. In the Mediterranean Sea, cessibility of sites. In order to overcome these pro- cases of loss of habitat-forming Cystoseira species blems we are developing methods to determine the (Fucales, Phaeophyceae) are numerous. If the losses abundance of intertidal seaweed habitats using a com- are massive for the species living deeper than 1 m bination of remote sensing and ground truthing. In this depth, little attention has been paid to the shallow spe- talk we compare assessments of coastal habitats based cies forming narrow belts just below the sea surface on high quality aerial imagery, freely accessible web- (infralittoral fringe), as the Mediterranean endemic C. map imagery and high resolution satellite data. We mediterranea. The species is widely distributed in the describe our approach using classification methods to Mediterranean Sea. In the western basin, its northern estimate and quantify the extent of coastal habitats limit is along the SW coast of France. We assessed the over time. We present results from two pilot studies past and current distribution of C. mediterranea in in the UK - Thanet, Kent and Isle of Wight, and France over the last 200 years. The species is known discuss the implications of this approach in ‘real- to only occur in French Catalonia and Languedoc. On time’ monitoring and use. the eastern French coasts, the species is replaced by its vicariant C. amentacea. The most recent distribution of C. mediterranea wasmappedinMay2012,80kmof 14OR.4 coast have been surveyed exhaustively and precisely TOLERANCE TO CLIMATE CHANGE OF (boating and snorkeling). In French Catalonia, the spe- EARLY LIFE-STAGE FUCUS VESICULOSUS cies is suffering a steady decline through the 20th cen- VARIES AMONG SIBLING GROUPS tury.From2003to2012,58%havebeenlost.Before 2003, the species was forming dense populations, Balsam Al-Janabi1 ([email protected]), Inken whereas it was only distributed in patches in 2012. Kruse1 ([email protected]), Angelika Graiff2 Lost populations were replaced by the opportunistic ([email protected]), Ulf Karsten2 less-structuring Corallina spp., encrusting corallinales ([email protected]) and Martin Wahl1 and mussels (Mytilus galloprovincialis) assemblages. ([email protected]) In the absence of increase of anthropogenic local stres- 1 sors, this recent decline might be due to the exceptional Benthic Ecology Department, GEOMAR - Helmholtz storms that hit the region in winter 2008 and 2010 and Center for Ocean Research, Kiel 24105, Germany 2 the subsequent mussel proliferations. Most worrying is and Institute of Biological Sciences, Applied Ecology the northern limit extinction in the 1980’satSèteand and Phycology, University of Rostock, Rostock 18059, Agde because of habitat destructions. In the remaining Germany natural stretches of coast, only abundant mussel and Corallina spp. assemblages were mapping. Given its Early life-stage of the bladderwrack Fucus vesiculo- natural dispersal capabilities the recovery of C. mediter- sus is highly influenced by the climate change factors fi ranea in the region appears unlikely. temperature, CO2 and eutrophication. Intraspeci c genetic diversity of Baltic Fucus vesiculosus populations is low, compared to e.g. Atlantic populations, which may limit their potential for adaptation. To 14OR.3 assess the role of intraspecific genetic diversity on CAN WE MONITOR CHANGES IN COASTAL the tolerance towards environmental change we HABITATS FROM OUR DESKTOPS? manipulated their diversity: Plots with full-sibling Keynote and Oral Papers 107 groups of Fucus germlings each originating from one physiological and ecophysiological characteristics of parental pair represents the low diversity level, Desmarestia anceps are well studied, until now no whereas plots with sibling groups from multiple par- study is available on the molecular processes under- ental pairs represent the high diversity level. Climate lying acclimation to abiotic stress. Within the frame- change was simulated according to the year 2100 in work of this study, we generated the transcriptome of the near-natural scenario Kiel Benthocosms by main- the brown alga Desmarestia anceps using the MiSeq taining the environmental fluctuations of the Baltic sequencing technology and tested for differential gene Sea and adding 5°C warming, 600 µatm pCO2 and expression in response to different light and tempera- doubling the nutrient concentrations. Germlings tures conditions using RNASeq and the HiSeq 2500 responded to warming with higher mortality and sequencer. We established a reference transcriptome enhanced growth rates. High pCO2 concentrations consisting of 20.2 million paired end reads, out of this, increased growth due to a fertilisation effect. Non- a total of 53,745 assembled transcripts were gener- photochemical quenching was lower under warmed ated, with contig length ranging from 301 bp to than ambient temperatures. A positive co-tolerance 37,509 bp. For investigating gene expression profiles among sibling groups towards warming and acidifica- of sporophytes were exposed for 24h to combinations tion indicates the possible attenuation in presence of of light intensities, UV radiation and temperatures (2, the multiple factors. Considerable differences among 7, 12°C). The highest numbers of differential sibling group performance indicate a higher adaptive expressed genes were found in response to the 12°C potential for genetically diverse populations. The high treatments, indicating that high temperatures are more diversity levels also showed higher survival, indicat- harmful for Desmarestia anceps than low tempera- ing possible facilitation processes among genotypes. tures, resulting in stronger efforts to overcome the Microsatellite genotyping is in progress for revealing negative effects. Desmarestia anceps responds to whether and how selection processes took place in abiotic stress with a multitude of transcriptional high diversity levels. We conclude that impacts on changes. Expression profile changes in several meta- early life-stage bladderwrack depend on the combina- bolic pathways including e.g. nucleotide metabolism, tion of stressors and season and that genetic variation lipid metabolism, and amino acid metabolism were is crucial for local adaptation to climate change stress. observed. UVR stress in general caused induction of nucleotide & lipid catabolism. A critical component of molecular acclimation mechanisms to high tempera- 14OR.5 ture stress in Desmarestia anceps is the induction of protein and lipid modification processes for maintain- TRANSCRIPTOMIC ACCLIMATION IN ing membrane and protein function. DESMARESTIA ANCEPS Sandra Heinrich1 ([email protected]), Lars Harms2 ([email protected]), Klaus Valentin3 14OR.6 ([email protected]) and Stephan Frickenhaus2 RECOVERY OF LARGE BROWN ALGAE ([email protected]) FORESTS AFTER DESTRUCTIVE FISHERY: 1 ECOLOGICAL RESTORATION INSIGHTS Functional Ecology, Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Luisa Mangialajo1,2 ([email protected]), Bremerhaven 27570, Germany; 2Computing and Fabrizio Gianni3 ([email protected]), Alexis Pey4 Data Centre, Alfred Wegener Institute Helmholtz ([email protected]), Laura Airoldi5 (laura.airol Centre for Polar and Marine Research, Bremerhaven [email protected]), Valentina Asnaghi6 (asnaghi.valenti 27570, Germany and 3Polar Biological [email protected]), Enric Ballesteros7 ([email protected]), Oceanography, Alfred Wegener Institute Helmholtz Emma Cebrian8,9 ([email protected]), Centre for Polar and Marine Research, Bremerhaven Mariachiara Chiantore10 ([email protected]), 27570, Germany Joachim Claudet11 ([email protected]), Simona Fraschetti12 (simona.fraschetti@unisalento. Brown algae of the order Desmarestiales dominate it), Maria Garcia9 ([email protected]) and Vesna rocky shores along the Antarctic Peninsula, where Macic13 ([email protected]) they form huge underwater forests providing habitat and nurseries for various marine organisms. 1Université de Nice-Sophia Antipolis, EA4228 Geographical distribution as well as the determination ECOMERS, Parc Valrose, Nice cedex 2 06108, of vertical patterns of macroalgae is constrained by France; 2Laboratoire d’Océanographie de abiotic factors such as light, including UV and tem- Villefranche, BP 28, Villefranche-sur-Mer 06234, perature. Therefore, global environmental changes France; 3Université de Nice-Sophia Antipolis, might have a negative impact on performance and EA4228 ECOMERS, Parc Valrose,, Nice cedex 2: survival of the Desmarestiales. Whereas the basic 06108, France; 4Université de Nice-Sophia Antipolis, Keynote and Oral Papers 108

EA4228 ECOMERS, Parc Valrose, Nice cedex 2 Marta Sales1 ([email protected]), Enric 06108, France; 5Dipartimento di Scienze Biologiche, Ballesteros2 ([email protected]), Eva Vidal3 (eva. Geologiche ed Ambientali, University of Bologna, Via [email protected]), Fiona Tomás4 (fiona.tomas@uib. S. Alberto 163,, Ravenna 48123, Italy; 6DISTAV, edu), Joan Moranta5 ([email protected]) and University of Genoa, corso Europa 26, Genoa 16132, Emma Cebrian6,7 ([email protected]) Italy; 7CEAB-CSIC, C/ d’accés a la Cala St. Francesc, 14., Blanes 17300,, Spain; 8Facultat de 1Estación Jaume Ferrer, Instituto Oceanográfico Ciencies Ambientales, Universitat de Girona, Girona Español, Maó 07700, Spain; 2Ecología Marina, 17071,, Spain; 9CEAB-CSIC, C/ d’accés a la Cala St. Centro de Estudios Avanzados de Blanes, Blanes Francesc, 14, Blanes 17300,, Spain; 10DISTAV, 17300, Spain; 3Estación Jaume ferrer, Instituto University of Genoa, corso Europa 26, Genoa 16132, Español Oceanografía, Maó 07700, Spain; Italy; 11University of Perpignan, CNRS, USR 3278 4IMEDEA, CSIC, Esporles 07190, Spain; 5Centre CNRS-EPHE CRIOBE, Laboratoire d’Exellence Oceanogràfic de les Illes Balears, Instituto Español CORAIL, Perpignan 66860, France; 12Dept. of Oceanografía, Palma de Mallorca 07015, Spain, Biological and Environmental Science and 6Ecología Marina, Centre d’Estudis Avançats de Technologies, Conisma, University of Salento,, Lecce Blanes, Blanes 17300, Spain and 7Dept. Ciències 73100, Italy and 13Institutza Biologiju Mora, Ambientals, Universitat de Girona, Girona 13700, Rukovodilac laboratorije, Naucni saradnik, P.Fah 69, Spain Kotor 85330, Montenegro The demise of large, long-lived species can lead to Marine forests of large brown algae are disappearing major seascape shifts. Such shifts have been widely worldwide due to several human impacts, such as observed in sublittoral habitats affected by environ- coastal urbanization, marine pollution and alteration of mental degradation, involving the disappearance of sedimentation rate. Proliferation of herbivores, often due kelps and other engineering species of seaweeds. to overfishing of predators or destructive fisheries, is Members of the genus Cystoseira (Fucales) are another major cause of loss of marine forests. In this important seascape makers in the Mediterranean, study, we assessed for the first time, the recovery of but are currently experiencing a severe decline as forests in an area highly impacted by the illegal fishing a consequence of environmental degradation. of the date mussel Lithophaga lithophaga, one of the Conservation and recovery of their populations most harmful human activities affecting subtidal rocky depends not only on the persistence of adults, but habitats. We tested the role of the limited dispersal of also on the successful recruitment and development Cystoseira species and the potential effect of herbivores of early life-history stages. However, recruitment of on Cystoseira recovery by crossing these two factors in a this genus is very limited, impeding the recovery of multifactorial orthogonal experiment in the field. Our decimated populations, even when the impact that experiment showed that he natural recovery of marine led to their regression has ceased. Here we assay forestscanbelowandseemstobelimitedbyboththe new techniques for restoring degraded Cystoseira low dispersal and by the presence of high densities of forests by artificially increasing recruitment. Two herbivores, in part a consequence of the destructive different restoration techniques have been tested. fishery. Ecological restoration of marine forests should The first one (in situ seeding) consisted in collect- be considered in particular cases, such as the date mussel ing fertile apical branches from a natural population destructive fishery (together with protection measures and placing them on a new locality. The second preventing poaching). Following our results, restoration technique (ex situ seeding) was similar but the actions should consider seedlings and may therefore fertile apical branches were placed on laboratory depend on the presence of reproductive individuals in seawater tanks; Cystoseira recruits were cultured the vicinity of the area to be restored. Major herbivores at the laboratory and transplanted to natural popula- (both sea-urchins and fish) should be excluded or regu- tions when they reached a height of 1 cm. The lated at least in the first phases of restoration protocol. As initial density of settlers was significantly higher stressed in previous work, the priority for management for the in situ seeding than for the ex situ seeding. of coastal ecosystems should always be the conservation However, those differences greatly decreased one of existing forests, by the institution of MPAs and the year after the beginning of the experiment, with implementation of targeted monitoring. greater mortalities on the in situ experiment. Two years after the restoration experiments, all Cystoseira populations were more or less bell- 14OR.7 shaped, and symmetric, peaking between 2-5 cm size classes, and with maximum heights of 13 and NEW METHOD FOR RESTORING 12 cm in the populations restored with the in situ CYSTOSEIRA DEGRADED FORESTS and the ex situ method, respectively. Both Keynote and Oral Papers 109 techniques are low cost and low time consuming natural, low-cost refugia for coralline algae from and might be applied for restoring threatened popu- ocean acidification.Aside of studies of lations of Cystoseira spp. “Tintenstriche” (= dark pigmented epilithic phototrophic communities on rock cliffs), records of endolithic Cyanobacteria from the European Alps are rare. We found a microbial community inhabit- 14OR.8 ing an episodically dry-fallen surface of a waterfall SLOW FLOW HABITATS AS REFUGIA FOR tufa in the Alps, forming one or two distinct black CORALLINE ALGAE FROM OCEAN to dark blue-green permanent endolithic layers in ACIDIFICATION 1-2mmand4-6mmbelowsurface,andata Catriona L Hurd ([email protected]) distance of 1-4 m from water-run areas. The waterfall tufa forms from ambient (non-thermal) waters Department of Botany/Institute for Marine and during episodes of increased runoff. Community Antarctic Studies, University of Otago/University of structure showing a prevalence of Cyanobacteria Tasmania, Hobart 7005, Australia was studied by culture-independent and culture- dependent approaches and covered light-and elec- Ocean acidification (OA) is the ongoing decline in tron microscopy (TEM) and molecular characteri- the pH of surface waters, and the projected 0.4 zation using 16S rRNA-based clone libraries. unit pH decrease by 2100 is likely to negatively Clonal inserts were screened by restriction frag- impact benthic coastal organisms that fabricate ment length polymorphism and individual restric- calcium carbonate ‘skeletons’. Coralline algae are tion types were sequenced. The limestone was considered the most vulnerable of all calcifying studied in epoxy-impregnated, petrographic thin organisms to ocean acidification. Research has sections under polarized light- and dark-field focussed on identifying susceptible species but microscopy. Although there is a relationship of we also need to identify refuge habitats to enable the endolithic community to the surface-dwelling their protection. The susceptibility of coralline “Tintenstrich” microflora, we found a smaller num- algae to OA depends on the pH at their surface, ber of taxa within the endolithic layers, which and this is regulated by the interplay between algal seem specifically adapted to this microenviron- metabolism and water motion. Algal metabolism ment. The endolithic microbial communities pre- causes local increases (photosynthesis, nitrate sumably consist mainly of limestone-dissolving uptake) and decreases (calcification, respiration, taxa rather than bio-calcifying taxa. The sub-milli- ammonium uptake) in the pH at the algal surface; meter sized pore spaces (parallel underneath the pH at the surface of a seaweed can thus fluctuate outer calcified surface of the waterfall tufa) they by ±0.5 units on a daily cycle. Water motion sets inhabit is filled with damp air rather than water; the thickness of the diffusion boundary layer, and this enables the community to withstand extended thickDBLshavebeenshowntoamelioratethe periods of drought as typical of central-alpine val- negative effects of ocean acidification on coralline leys during summer. The functional groups of algae via their action of retaining metabolically Cyanobacteria in the endolithon are composed of, produced high-pH seawater at the algal surface, both, nitrogen fixers (Dichothrix sp.) and non-N- thereby preventing dissolution of calcium carbo- fixers (Aphanothece sp.), adapted to low-light con- nate. Seawater velocities within beds of canopy ditions; in the epilithon high-light and desiccation- forming seaweed, including members of the orders tolerant taxa were recorded (Gloeocapsa alpina, Laminariales and Fucales, are much reduced (75- Gloeocapsopsis sp., Chondrocystis sp.). Nostoc 95%) compared to the mainstream seawater velo- sp., however, was common in the cultures from city. Such slow-flow habitats may thus provide both habitats. Keynote and Oral Papers 110

15. Algae and Signalling - regulation of processes from cell to globe

15KN.1 15OR.1 LIPID SIGNALING IN PLANKTON EXPRESSION OF A PKSIII GENE AND COMMUNITIES SOLUBLE PHLOROTANNIN SYNTHESIS IN 1 RESPONSE TO ABIOTIC AND BIOTIC Erik Selander ([email protected]), Julia FUCUS 2 STRESSES IN THE BROWN ALGA Kubanek ([email protected]), VESICULOSUS 3 : CONSTITUTIVE VERSUS Carina Berglund ([email protected]), INDUCTIVE PROTECTION Mats X Andersson3 ([email protected]), Mats 1 1 Hamberg4 ([email protected]), Gunnar Cervin5 Philippe Potin ([email protected]), Emeline Creis 1 ([email protected]), Pia Engström6 ([email protected]), Ludovic Delage 2 ([email protected]) and Henrik Pavia5 (henrik. ([email protected]), Laurence Meslet-Cladière 1 [email protected]) ([email protected]), Laurent Vallet ([email protected]), Erwan Ar Gall3 1Biological and Environmental Sciences, Göteborg ([email protected]), Inken Kruse4 (ikru 4 SE-40530, Sweden; 2School of Biology and School of [email protected]), Florian Weinberger (fweinber 5 Chemistry and Biochemistry, Georgia Institute of [email protected]), Sophie Goulitquer (sophie.goulit Technology, Atlanta GA30332, United States; [email protected]), Sophie Charton6 (sophiecharto 1 3Biological and Environmental Sciences, Göteborg [email protected]) and Catherine Leblanc (leblanc@ SE-45030, Sweden; 4Department of Medical sb-roscoff.fr) Biochemistry and Biophysics, Stockholm SE-17177, 1 Sweden; 5Biological and Environmental Sciences, Integrative Biology of Marine Models, CNRS- Strömstad SE-45296, Sweden and 6Biological and University Paris 6, ROSCOFF Cedex 29688, France; 2 Environmental Sciences, Fiskebäckskil SE-45034, Integrative Biology of Marine Models, CNRS- Sweden University Paris 6, ROSCOFF Cedex 29688, France; 3LEMAR, University of Brest, Plouzané 29280, 4 Zooplankton organisms release chemical compounds France; Marine Ecology Division, GEOMAR into the surrounding water that induce pivotal changes Helmholtz-Zentrum für Ozeanforschung, Kiel 5 in phytoplankton prey. Few of these signaling molecules D-24105, Germany; Metabomer core facility, CNRS- have, however, been identified. Here we discuss the role University Paris 6, Roscoff cedex 29688, France and of polar lipids as signals in the marine pelagic exempli- 6Integrative Biology of Marine Models, CNRS- fied by a group of novel signaling lipids, the copepoda- University Paris 6, ROSCOFF cedex 29688, France mides. Copepodamides constitute at least 12 closely related taurine conjugated lipids released by copepods. Brown algal phlorotannins are structural analogues Harmful alga respond to pico-, to nanomolar concentra- of terrestrial plant condensed tannins and similar to tions of copepodamides by inducing defensive traits plant phenols that carry numerous bioactive func- such as production of saxitoxins (paralytic shellfish tox- tions. These molecules are largely studied in the ins), and changes in morphology. Copepods have spe- chemical ecology of Phaeophyceae because of cies-specific copepodamide composition allowing for their interesting activities including as antioxidant high specificity in interactions with responding organ- and anti-microbial, anti-appetant and bio-adhesive isms. We present exudation rates, dose response relation- capacities. However, phlorotannin biosynthetic ships for prey organisms, depth resolved distribution of pathways have been hardly characterized at the copepods and copepodamides in costal water, as well as molecular level. We found that a predicted type the composition of copepodamides in common NE III polyketide synthase in the Ectocarpus genome, Atlantic copepods. Copepods are ubiquitous in aquatic EsiPKS1 heterologously expressed in E. coli,cat- habitats and copepodamide signaling may consequently alyzes a major step in the biosynthetic pathway of have large-scale effects in pelagic food webs. Finally, we phlorotannins, i.e. the synthesis of phloroglucinol argue that polar lipids may be an important group of monomers using malonyl-CoA. Phlorotannins are signals based on the copepodamides and additional then formed by the condensation of phloroglucinol recently described lipid signals from the marine pelagic. units, however, the following steps in this Keynote and Oral Papers 111 biosynthetic pathway are still unclear. The confir- vesiculosus revealed that fucoxanthin and proline mation of the first step has been used in order to concentrations are higher on surfaces of elicited better understand the mechanisms that regulate this specimens, while DMSP concentrations are unaf- metabolism in brown algae. By combining inte- fected by this treatment. In the case of fucox- grated approaches of gene expression, quantifica- anthin, increased surface concentrations were tion and profiling of soluble phlorotannins, we correlated with decreased tissue concentrations, have shown that these metabolites ensure the con- which hints at an induced translocation of fucox- stitutive protection in Fucus vesiculosus exposed anthin from chloroplasts to the algal surface within to UV-B radiation and could also be induced very 24 h after oligoguluronate recognition. We con- early during grazing. The development of these clude that oligoguluronate must be perceived like specific molecular tools opens some new perspec- a pathogen-associated molecular pattern in mem- tives in ecophysiological and ecological studies of bers of the Fucales, inducing a non-specificdeter- the functions of brown algal phenolic compounds. rent response against microbial settlers. We also present results from a comparable study on Taonia atomaria, a member of the Dictyotales. 15OR.2 INNATE IMMUNITY REGULATES THE EXCRETION OF ANTI-SETTLEMENT 15KN.2 COMPOUNDS BY FUCUS VESICULOSUS AND OTHER BROWN SEAWEEDS A CHEMICAL ARMS RACE MEDIATES HOST- VIRUS INTERACTIONS DURING ALGAL 1 Florian Weinberger ([email protected]), BLOOMS IN THE OCEAN Göran Nylund2 ([email protected]), Gerald Culiuli3 ([email protected]) and Jean- Assaf Vardi ([email protected]) Francois Briand4 ([email protected]) Department of Plant and Environmental Sciences, 1Benthic Ecology Department, GEOMAR Helmholtz Weizmann Institute of Science, Rehovot 76100, Israel Center for Ocean Science, Kiel D24105, Germany; Marine viruses that infect marine microorganisms 2The Lovén Centre Tjärnö, University of Gothenburg, are recognized as major ecological and evolutionary Strömstad SE45296, Sweden; 3Laboratoire driving forces, shaping community structure and MAPIEM-EA 4323 - “Biofouling & Substances nutrient and energy cycling in the marine environ- Naturelles Marines”, University of Toulon, La ment. Nevertheless, the cellular mechanisms that Valette-du-Var F-83162, France and 4Laboratoire govern these host-virus dynamics are largely unex- MAPIEM-EA 4323 - “Biofouling & Substances plored. Emiliania huxleyi is a globally important Naturelles Marines”, University of Toulon, La coccolithophore forming massive algal blooms in Valette-du-Var F-83162, France the North Atlantic Ocean that are routinely infected Oligoguluronates are known as pathogen-asso- and terminated by large DNA viruses, coccolitho- ciated molecular patterns that activate oxidative viruses (EhVs). This unique host-pathogen interac- burst responses and induce defense-related protein tion spans more than 12 orders of magnitude, from the individual cell (~10−6 m) to large algal blooms expression in sporophytes of Laminariales. In con- 6 trast, most other brown seaweeds – for example (~10 m). We therefore aim to bridge this gap by members of Fucales or Dictyotales - were up to investigating both the intricate cellular mechanism now considered as incapable of oligoguluronate induced during host-virus interactions as well as recognition, as oxidative burst responses after chal- studying the mechanism of viral transmission over lenge with this signal are usually not observed. the large scale of algal blooms. We explore the Here we show that exposure of Fucus vesiculosus molecular basis for host-virus dynamics and the and Sargassum muticum to oligoguluronate results signal transduction pathways that mediate host nonetheless in a defensive response that targets resistance and susceptibility to viral infection. microbial settlers. At natural concentration surface Major efforts in our lab are focused on the role of extracts from elicited specimens of both species sphingolipid and ROS metabolism and their func- were significantly more deterrent to bacteria than tion in host PCD and autophagy during viral repli- surface extracts from unelicited specimens. Since cation strategies. The high prevalence of viral- this effect was not observed 1 h after challenge encoded metabolic enzymes from aquatic systems with oligoguluronate, but observed 1 – 3dafter strongly points to their central role in shaping the ‘ ’ elicitation, it was suggested that it was an induced evolutionary arms race between marine microbes fl rather than an activated response. A targeted ana- and their viruses, and consequently, the ow of lysis of established deterrent compounds from F. carbon in marine food webs Keynote and Oral Papers 112

15OR.4 15OR.3 ENVIRONMENTAL VOLABOLOMICS: SIGNALLING IN BACTERIAL-MACROALGAL DECIPHERING THE CHEMICAL LANGUAGE SYMBIOSIS: CHEMOTAXIS IS INVOLVED IN THAT SHAPES AQUATIC HEALTH BIOFILM FORMATION BY ROSEOBACTER SP. 1 Michael Steinke ([email protected]), Bettina AND ULVA MUTABILIS (CHLOROPHYTA) 2 Hodapp ([email protected]), Dominik Anne Weiss ([email protected]), Ralf W Martin-Creuzburg2 (Dominik.Martin- Kessler ([email protected]), Stefan Kügler [email protected]), Rameez Subhan1 ([email protected]) and Thomas Wichard ([email protected]), Sarah Lemaire1 (slemai@es ([email protected]) sex.ac.uk) and Alex Dumbrell1 ([email protected])

Institute for Inorganic and Analytical Chemistry, 1School of Biological Sciences, University of Essex, Friedrich Schiller University Jena, Jena 07743, Colchester CO4 3SQ, United Kingdom and Germany 2Limnological Institute, University of Konstanz, Konstanz 78464, Germany The marine macroalga Ulva mutabilis (Chlorophyta) is developing into callus-like colonies consisting of All natural systems emit biogenic volatile organic undifferentiated cells with abnormal cell walls under compounds (BVOCs) that can affect atmospheric axenic conditions. From the associated microbial flora, processes and climate. It is also likely that volatiles Roseobacter sp. (MS2) and Cytophaga sp. (MS6) are carry information on the physiological status of the able to induce the complete algal morphogenesis via emitter and that they alter physiological functioning morphogenetic compounds forming a tripartite com- and behaviour across trophic levels in aquatic food munity. Interestingly, the motile Roseobacter sp. estab- webs. Our understanding of the ecology and phy- lishes a biofilm around the primary rhizoid cells of siology of key volatiles such as isoprene (C5H8) Ulva mutabilis. Using this standardised tripartite and dimethyl sulfide (DMS; (CH3)2S) is steadily model system, we are now able to address various growing. However, the signature qualities of the aspects on the cross-kingdom cross talk. We tested entire suite of BVOCs produced from single indivi- the hypothesis if the biofilm formation would be duals to entire ecosystems, the volatile metabolome mediated by the attraction of the bacteria through che- or ‘volabolome’, and its sensitivity to disturbance motaxis-inducing algal signals. Therefore, a bioassay- are poorly explored. Using gas chromatography, we guided approach was developed using different solid characterised the volabolomes of four freshwater phases for extraction covering a wide range of polarity. genera (Chlamydomonas, Cyclotella, Cryptomonas, The bioassay was based on the attraction of Aphanizomenon), before quantifying the volabo- Roseobacter sp. towards algal extracts in a capillary lomes of the marine dinoflagellate Symbiodinium chemotaxis assay. We isolated two biologically active sp. and the diatom Thalassiosira pseudonana at fractions by hydrophobic and hydrophilic interaction two temperatures. Principal Component Analysis chromatography. The analysis of the hydrophilic frac- (PCA) demonstrated clear separation of algal genera tion by HILIC-MS (hydrophilic liquid interaction chro- based on their volabolome signatures with signifi- matography coupled to a mass spectrometer) revealed cant differences in the first and second principal dimethylsulfoniopropionate (DMSP) as both a possible component scores across genera (ANOVA; PC1, chemotactically active and bacterial growth-promoting F3,8 = 38.8, P <0.001; PC2, F3,8 = 8.2, P <0.01). factor, whereas the factor, extracted by the hydrophobic All taxa could be separated based on principal solid phase, is still unknown. To obtain a holistic pic- component one scores (Tukey’s HSD, P < 0.05) ture of the dynamics of DMSP in the tripartite commu- other than Chlamydomonas from Aphanizomenon nity, we quantified the dissolved amount of DMSP in which had significantly different principal compo- the Ulva growth medium and performed uptake experi- nent two scores (P < 0.05). The volabolomes of ments of deuterium-labelled DMSP with Roseobacter Symbiodinium sp. and the diatom Thalassiosira sp. under minimal medium conditions. The intracellu- pseudonana grown at 26 °C were different after a lar DMSP amount indicates a rapid uptake along with a step-wise temperature increase to 31 °C over 5 fast metabolisation by Roseobacter. Besides the che- days. Much of this difference was driven by a motactic activity of DMSP, the growth of Roseobacter significant increase in isoprene and DMS. Our is supported. In summary, the study provides informa- investigations demonstrate that algal volabolomes tion about the DMSP-mediated physiological relation- are taxon-specific and affected by environmental ship between a Roseobacter species and the green conditions. Deciphering this chemical language is macroalga Ulva mutabilis, and elucidates the role of an important challenge that could help understand- the algae in shaping this mutualistic relationship. ing the regulation of processes from cell to globe. Keynote and Oral Papers 113

16. Special Session: PHYCOMORPH

fi 16KN.1 vectors introduced ef ciently in Ulva gametes for expression of GFP or insertion mutagenesis. Due to EXPLORING BACTERIA-INDUCED the methods developed, U. mutabilis is now well MORPHOGENESIS IN THE GREEN suited to model studies in developmental biology. MACROALGA ULVA (CHLOROPHYTA): A Reference: Wichard, T. (2015) Frontiers in Plant COMBINED CHEMICAL AND GENETIC Science 6:86. APPROACH Thomas Wichard ([email protected]) 16KN.2 Institute for Inorganic and Analytical Chemistry, Friedrich Schiller University Jena, Jena 07743, PLANT HORMONES AND REPRODUCTION Germany IN RED SEAWEEDS: FROM THE CHEMICALS TO TRANSCRIPTOMICS Growth, development and morphogenesis of Ulva Pilar García-Jiménez ([email protected]) and depend on its associated bacteria. Axenic algal germ Rafael R Robaina ([email protected]) cells develop just into callus-like colonies consisting of undifferentiated cells. Interestingly, the complex Biología, Facultad de CC del Mar. Universidad de natural bacterial community from Ulva mutabilis Las Palmas de GC, Las Palmas GC 35017, Spain (Føyn) can be replaced by just two isolated strains, Roseobacter sp. and Cytophaga sp., which recover the An overview will be given of the advances in our complete morphogenesis applied to axenic gametes. understanding of the intervention of plant hormones Using this standardized tripartite community, our in the reproductive events of the red seaweeds, that will research aims to explore the (i) signal-mediated coop- be linked to the main tasks of the Phycomorph COST erative interactions between kingdoms, (ii) the biofilm ACTION (FA1406). The development of reproductive formation at the algal holdfast and (iii) the role of structures of red seaweeds and their sporulation are bacteria in algal germination and morphogenesis. affected by the polyamines and the gaseous hormone The identification of potential growth-stimulating ethylene. As cystocarp matured, polyamines putrescine and morphogenetic bacterial substances is hereby (Put), spermidine (Spd) and spermine (Spm) were essential to the understanding of signal mediated accumulating, favoring the development of cystocarps. cross-kingdom interactions within the chemosphere Particularly Spm promoted sporulation in several rho- of U. mutabilis. To unravel the chemosphere two dophytes like Hydropuntia cornea (formerly major approaches are followed in analytical chemis- Gracilaria cornea)andGrateloupia imbricata. try: (i) bioassay guided fractionation and (ii) unbiased Exogenous ethylene favoured the increment in tetra- metabolite profiling of the exo-metabolome based on sporangial branches and cystocarps in the red seaweeds GC/MS and LC/MS analyses after solid phase extrac- Pterocladiella capillacea and G. imbricata respec- tion. It turned out that the exo-metabolome is directly tively. The synthesis of polyamines starts with the influenced by environmental stimuli including the decarboxylation of ornithine by the ornithine decarbox- bacterial community associated with U. mutabilis. ylase (ODC, EC. 4.1.1.17) to produce putrescine, The consistent combination of classical bioassays which is then transformed in spd and spm by adding and explorative analytical methods revealed novel groups from S-adenosyl methionine SAM. In G. imbri- insights into the complex networks of infochemicals cata, the gene GiODC has been shown to be involved and signal molecules along with their ecophysiologi- in cystocarp development, and it also has been shown cal significance. However, the underlying molecular that its expression seems to depend on spatial and mechanism of changes in morphologies needs further temporal regulation that is associated with the progress investigations preferentially by utilization of a work- of cystocarps, as the number of GiODC transcripts ing genetic system. As a result, the transformation of abruptly decreases after cystocarp maturation. The Ulva by vector plasmid integration into the genome synthesis pathways of the polyamines and ethylene, was developed (W. Oertel, T. Wichard, A. thus share the same precursor SAM. In recent years, Weissgerber, Journal of Phycology, in revision): The different molecular approaches (iPCR, NGS) have chromosomal Ulva-RbcS gene was used for designing been used to understand molecular mechanisms in red a dominant selective marker cassette for shuttle seaweed reproduction. Particularly, we have focused Keynote and Oral Papers 114 on: (i) how far the elicitors involved in cystocarp Silje Forbord ([email protected]), Jorunn development affect to the level of GiODC expression, Skjermo ([email protected]), Kristine (ii) unravelling of the pathway(s) and the components Steinhovden ([email protected]) and of signaling for different elicitors involved in the sea- Aleksander Handå ([email protected]) weed reproduction, and (iii) the functional analysis of transcriptome of G. imbricata with particular emphasis Fisheries and Aquaculture, SINTEF, Trondheim 7465, on detecting candidate genes potentially involved in Norway metabolism of growth regulators. Meeting the demands for food and energy from a global population growth of 2 billion people, reaching 9 billion 16KN.3 before 2050, will require millions of tons of new biomass resources. The European seaweed industry has COMPARATIVE ANALYSIS OF CAULERPA recently expanded by the establishment of several com- AND LAND PLANT TRANSCRIPTOMES: panies aiming for cultivation and processing of seaweed IMPLICATIONS FOR KAPLAN’S biomass for a commercial marked. There are, however, ORGANISMAL THEORY needs for both, cost effective cultivation methods for Dan Chitwood ([email protected]) production of the seaweed biomass in predictable quantity and quality, as well as new processing methods that Donald Danforth Plant Science Center, Donald ensure valuable compounds or products to be derived Danforth Plant Science Center, St. Louis, MO 63132, fromtherawmaterialpreferablyinawaythatenablesa United States complete utilization of the biomass. An industry based on processing of cultivated seaweed requires a stable Convergent morphologies have arisen in plants multiple and predictable delivery of biomass with defined quali- times. In non-vascular and vascular land plants, conver- ties. The cultivation biology has to be developed to gent morphology in the form of roots, stems, and leaves guarantee this, but there are still many challenges and arose. The morphology of some green algae includes an limitations that need to be solved before the seaweed anchoring holdfast, stipe, and leaf-like fronds. Such aquaculture can meet this demands. Some important morphology occurs in the absence of multicellularity in biological challenges are: 1. Biofouling on the cultivated the siphonous algae, which are single cells. seaweed restricts the cultivation period and diminish the Morphogenesis is separate from cellular division in the commercial value of the biomass for use as human land plants, which although are multicellular, have been consumption and industrial applications.2. The proces- argued to exhibit properties similar to single celled sing industry requires a predictable content of demanded organisms. Within the single, macroscopic cell of a components in seaweed (carbohydrates, proteins, miner- siphonous alga, how are transcripts partitioned, and als, anti-oxidants and other high valuable components), what can this tell us about the development of similar but due to seasonal and environmental conditions in the convergent structures in land plants? Here, I will present growth period, large variations are found.3. New species a de novo assembled, intracellular transcriptomic atlas with demanded properties such as fast growth rate, low for the giant coenocyte Caulerpa taxifolia. Transcripts biofouling activity and valuable chemical content are show a global, basal-apical pattern of distribution from attractive for aquaculture, but cultivation protocols theholdfasttothefrondapexinwhichtranscriptiden- need to be developed.4. Viral, bacterial and fungal dis- tities roughly follow the flow of genetic information in eases may cause problems in this emerging aquaculture the cell, transcription-to-translation. The analysis of the industry and measures to enhance the resistance against intersection of transcriptomic atlases of a land plant and seaweed diseases will be required. Caulerpa suggests the recurrent recruitment of transcript accumulation patterns to organs over large evolutionary distances. Our results not only provide an intracellular 16KN.5 atlas of transcript localization, but also demonstrate the contribution of transcript partitioning to morphology, MACROALGAL DEVELOPMENT AND independent from multicellularity, in plants. MORPHOGENESIS: DEPLOYING A NEW INTERNATIONAL INITIATIVE TO ADVANCE KNOWLEDGE AND TRANSFER 16KN.4 Bénédicte Charrier ([email protected])

SUCCESSFUL SEAWEED AQUACULTURE Station Biologique, CNRS, Roscoff 29680, France BASED ON FUNDAMENTAL BIOLOGICAL KNOWLEDGE - WHAT ARE THE MAIN Macroalgae develop macroscopic bodies through a CHALLENGES? high diversity of processes including the regulation Keynote and Oral Papers 115 of cell division and cytokinesis, cell-cell communica- to be solved. Therefore, combining the skills of tion, diffusion of endogenous signalling molecules, phycologists and plant biologists all involved in complex chemical interactions with bacteria, and the basic and applied studies of macroalgal development, integration of diverse environmental cues. Beside this the recent European COST network PHYCO complexity rivaling with that of other major macro- MORPH. (http://www.cost.eu/COST_Actions/fa/ scopic organisms like land plants, the number of stu- Actions/FA1406) aims at developing and coordinat- dies dedicated to this field is limited, making the ing this research field so that significant progresses are current knowledge about the precise developmental made which allow future accurate and cutting-edge processes in macroalgae very incomplete. In addition development of modern aquaculture techniques. The to having macroalgal basic sciences hanging back, talk will present PHYCOMORPH and illustrate its progresses in seaweed aquaculture are impeded, as objectives through a few examples of current studies current bottlenecks for an improved and cost-effective as highlighted in the recent research topic of Frontiers seaweed biomass production require a deeper and in Plant Science (http://journal.frontiersin.org/ more specific knowledge of macroalgal development researchtopic/2598). Keynote and Oral Papers 116

Manton session

MANTON.1 in these understudied fungi-algae mutualistic rela- BIODIVERSITY, SECONDARY tionships. We are now exploring this concept METABOLOME AND ECOLOGICAL ROLE further via the development of tripartite bioassays, OF FUNGAL ENDOPHYTES ASSOCIATED where the interaction between the endophyte and WITH THE BROWN ALGAE LAMINARIA some known pathogens will be measured in vivo. DIGITATA, ASCOPHYLLUM NODOSUM, SACCHARINA LATISSIMA AND PELVETIA CANALICULATA MANTON.2 Marine Vallet1 ([email protected]), Kady Du1 2 TWO-PHASED CELL POLARISATION IN THE ([email protected]), Martina Strittmatter BROWN ALGA DICTYOTA ([email protected]), Joëlle Dupont3 1 ([email protected]) and Claire MM Gachon2 (Claire. Kenny A Bogaert ([email protected]), Tom 2 [email protected]) Beeckman ([email protected]) and Olivier De Clerck1 ([email protected]) 1Unité MCAM, UMR 7245 CNRS/MNHN, Natural 1 History Museum of Paris, Paris 75005, France; Biology Department, Ghent University, Ghent 9000, 2 2Microbial and Molecular Biology Department, Belgium and Department of Plant Biotechnology and Scottish Marine Institute, Oban Argyll PA37 1QA, Bioinformatics, Ghent University, Ghent 9052, Belgium United Kingdom and 3Unité OSEB, UMR 7205 CNRS/MNHN, Natural History Museum of Paris, In most complex eukaryotes development com- Paris 75005, France mences with the establishment of cell polarity that determines the first axis of the future body Morphologically-complex brown algae are colo- plan. The underlying mechanisms of polarity nized by endophytic fungi that do not cause appar- establishment are still emerging. Using a combi- ent damage on their host. In plants, endophytes nation of microscopy, pharmacological experi- protect their host against biotic and abiotic stress, ments and transcriptomic analyses we show that presumably through the production of metabolites. cell polarity in the brown alga Dictyota is estab- However, in macroalgae, the study of the diversity lished in a two-phased process with the first phase and the role of endophytic fungi associated with narrowing down the possible polarisation vectors seaweeds are still largely unexplored. In this con- to a set of two. Like in land plants, the zygote of text, we determined the diversity of culturable Dictyota establishes the apical-basal axis during fungal endophytes in Laminaria digitata, Asco the first cell division. Upon egg activation, the phyllum nodosum, Saccharina latissima, Pelvetia zygote undergoes an F-actin/myosin dependent, caniculata. 121 fungal strains were thus isolated 90s lasting elongation along a maternally deter- from algae sampled in France and Scotland, which mined axis that is reflectedinthecytoplasmic grouped into more than 40 molecular operational distribution of plastids. Which of the two poles taxonomic units. Selected marine ascomycete of the resulting prolate spheroidal zygote will strains such as Dendryphiella spp were chemically acquire the basal cell fate, is determined environ- studied and new fungal metabolites were isolated mentally as assessed by the direction of unilateral and characterized. In order to evaluating the poten- light. The second phase is accompanied and tial role of fungal endophytes within the symbiosis dependent on zygotic transcription instead of relationship with their algae host, activity of these uniquely on maternal factors. In that embryogen- fungal metabolites against pathogens of brown esis in brown algal plant systems is more similar algae was tested (Eurychasma dicksonii, to higher plants rather than animal system. Cell Anisolpidium ectocarpii, Maullinia ectocarpi, polarisation as observed in Dictyota whereby Pseumodomonas alginovora, Pseudoalteromonas determination of direction and sense of the bacteriolytica). Some of them exhibited potent polarisation vector are mechanistically and tem- antioomycete or antibacterial activities against porally decoupled, in two distinct processes is pathogens suggesting a plausible ecological role unique. Keynote and Oral Papers 117

MANTON.3 1Chemical and Biological Engineering, University of fi fi THE IMPORTANCE OF REVEALING Shef eld, Shef eld S13JD, United Kingdom and 2 fi CRYPTIC DIVERSITY IN RELATION TO Animal and Plant Sciences, University of Shef eld, fi ASSESSING THE STRUCTURAL INTEGRITY Shef eld S102TN, United Kingdom OF THE MAERL BED HABITAT In 2012, a report from the Algal Biotechnology Special Leanne A Melbourne ([email protected]) Interest Group identified a wide range of ways in which algae could be converted to biofuels and bioenergy. Earth Sciences, University of Bristol, Bristol BS8 1RJ, The report identified bioremediation as a feasible and United Kingdom cost effective source of algal feedstock. Therefore, we aimed to gain a better understanding of bioremediation Rhodoliths, non-geniculate coralline red algae that can targets such as natural microalgal blooms. The goal exist as free-living fragments, are an important habitat- was to gain insights into large-scale production of forming (maerl) group. Around the UK they are the algal communities for bioenergy as well as helping to fi major calci ed habitat formers, with maerl beds found understand whether harvesting from the natural envir- in south-west England (Falmouth) and around Scotland. onment is a feasible approach for feedstock generation. Due to the structural and functional complexity of these The aim of our study was to undertake a multi-para- organisms, they support a high level of biodiversity. meter analysis of a microcosm simulating a freshwater Their susceptibility to climate change makes them lake under bloom conditions. An artificial bloom was ideal candidates to study the effects of ocean warming induced in 15 L microcosms, which were inoculated fi and acidi cation. However, little research has focused with an environmental sample and grown in constant on their structural integrity and whether, in future CO2 light and temperature using a freshwater lake-simulat- conditions, they will be able to continue to support a ing medium. Measurements of water quality (pH, tem- high level of biodiversity. Using Finite Element + perature,DO),chemistry(NH4 ,NO3-, PO4-) and Modelling, previous research employing 2D models biomass (chlorophyll, cyanobacteria, bacteria) were suggested that under future CO2 conditions coralline undertaken. We applied a multivariate statistical algae were more prone to fracture. Here we compared approach to examine the role of water quality and 3D geometric cubes representing various coralline algal nutrients on the spatiotemporal structure and composi- features with biologically accurate models derived from tion of functional microbial groups. We coupled this computed tomography scanning. In doing so, we have with a metagenetic survey of population composition been able to show that these 3D cubes can accurately and a metaproteomic study, which provided a signature represent the coralline algal skeleton. Results reiterated of ecosystem function. Together with multivariate ana- that future CO2 conditions will cause these skeletons to lysis, ‘omics technologies provide an understanding of be more prone to fracture. With responses to climate community composition and a signature of ecosystem fi change being species-speci c, it is important to have an function. The interpretation of the community profiles understanding of the species within these maerl beds. provided enhanced understanding of bloom formation fi Hence, an identi cation study was performed using for predictability (restoration goal) and control (culti- molecular techniques on specimens from the Fal (south vation goal). UK) and Berwick upon Tweed and Oban (north UK). Results revealed a new species of Lithothamnion in the north and it was concluded that there was no evidence of Lithothamnion lemoineae, which had previously been MANTON.5 recorded in the UK. We can now tailor our models to be MATING TYPE RELATED GENES IN species-specific and therefore make accurate predictions PSEUDO-NITZSCHIA MULTISTRIATA as to how the structural integrity of these rhodoliths will Laura Vitale1 ([email protected]), Shrikant Patil1 be affected in future global change and consequently the ([email protected]), Swaraj Basu2 (swaraj. impact this will have on the organisms that are supported [email protected]), Remo Sanges2 ([email protected]), within the habitat. Maria Immacolata Ferrante1 (mariella.ferrante@szn. it) and Marina Montresor1 ([email protected]) MANTON.4 1Integrated Marine Ecology (EMI), Stazione MULTIDISCIPLINARY ANALYSIS OF A Zoologica Anton Dohrn, Naples 80121, Italy and FRESHWATER LAKE MICROBIAL 2 Biology and Evolution of Marine Organisms COMMUNITY UNDER DIFFERING (BEOM), Stazione Zoologica Anton Dohrn, Naples NUTRIENT REGIMES 80121, Italy David Russo1 (d.russo@sheffield.ac.uk), Jagroop Pandhal1 (j.pandhal@sheffield.ac.uk) and Andrew Sexual reproduction is a fundamental phase in the life Beckerman2 (a.beckerman@sheffield.ac.uk) cycle of diatoms, linked to the production of Keynote and Oral Papers 118 genotypic diversity and the formation of large-sized three species of benthic dinoflagellates remain the initial cells that ensure population persistence. It only described species in the genus. During our occurs only within cells below a certain threshold research, we have isolated 14 strains that have been size and, in heterothallic diatoms only between strains assigned to this genus based on morphological obser- of opposite mating types. We aim at identifying genes vations and phylogenetic analyses. These strains were involved in mating type determination in the marine isolated from samples from seabed sampling sites in planktonic diatom Pseudo-nitzschia multistriata. This sub-tropical waters of the Kagoshima and Okinawa species is recorded in coastal waters worldwide and prefectures, Japan. In this presentation, we shall elu- produces the neurotoxin domoic acid. A reference cidate the diversity of the genus Testudodinium. The genome has been generated and transcriptomes have strains fall into four major clades within been produced for strains of opposite mating type (MT Testudodinium, three of which contain a described + and MT-). Differential expression analysis provided species. The fourth clade consists of four species that a list of putative MT-linked transcripts that were then are characterised by a hypocone with a rugose dorsal validated with qRT-PCR using independent strains. surface and by the presence of a unique internal fea- Four MT-related genes were identified, two over- ture, props, which are distributed throughout the cell, expressed in MT+ and two over-expressed in MT-. spanning the height of the cell. The clade including T. The expression pattern of the candidate genes was maedanese does not consist of the single described followed in a 24 hours time course experiment to species but forms a species complex of morphologi- verify whether they were regulated in dependence of cally indistinguishable strains. The clade containing light or cell cycle phases. Experimental evidences the two strains described as T. corrugatum contains demonstrated their involvement during mating recog- two novel species. None of our strains appear to be nition in early stages of sexual reproduction while related to the type species T. testudo, either morphogenetic analyses excluded that they could be the mas- logically or phylogenetically. In conclusion, we show ter gene responsible for mating type determination. that the genus Testudodinium is far more diverse than Expression of the candidate genes has been analyzed the described species indicate. also in samples below and above the sexualization size threshold (SST). Functional analysis is ongoing to understand their role in the chemical communication MANTON.7 occurring between opposite mating types. Elucidating the molecular and genetic basis of MT determination NUTRIENT AND LIGHT RESPONSES IN TWO and sexual reproduction in diatoms will contribute to a ESTUARINE RHODOPHYTES: better understanding of the regulation and evolution of IMPLICATIONS FOR THEIR ZONATION their life cycles and reproductive strategies. Results Raquel Sánchez de Pedro Crespo1 ([email protected]), from this study could also provide molecular markers F Xavier Niell1 ([email protected]) and Raquel to trace the distribution of MT+ and MT- cells in Carmona2 ([email protected]) environmental samples. 1Departamento de Ecología, Facultad de Ciencias, Universidad de Málaga (UMA), Málaga 29071, Spain 2 MANTON.6 and Departamento de Ecología, Facultad de Ciencias, Universidad de Málaga (UMA), Málaga DIVERSITY AND PHYLOGENY OF THE 2907, Spain DINOFLAGELLATE GENUS TESTUDODINIUM (DINOPHYCEAE) This study examines how photoacclimation and nutri- Sohail Keegan Pinto1 ([email protected]. ent uptake responses can affect the zonation of jp), Ryuta Terada2 (terada@fish.kagoshima-u.ac.jp) Bostrychia scorpioides and Catenella caespitosa, and Takeo Horiguchi3 ([email protected]) two epiphytic red macroalgae that grow spatially seg- regated in the narrow intertidal zone of Palmones 1Department of Natural History Sciences, Graduate estuary (South of Spain). Uptake rates of ammonium, School of Science, Hokkaido University, Sapporo nitrate and phosphate and changes in photosynthesis- 060-0810, Japan; 2Department of Fisheries, Faculty and growth-irradiance curves were measured at con- of Fisheries, Kagoshima University, Kagoshima centrations and light levels found in the field. 890-0056, Japan and 3Department of Natural History Bostrychia scorpioides presented higher uptake rates + Sciences, Faculty of Science, Hokkaido University, than C. caespitosa for N-sources, especially for NH4 , Sapporo 060-0810, Japan the most abundant N form in the estuary. On the contrary, C. caespitosa had a greater capability for The genus Testudodinium was established in 2012, phosphate uptake. Turnover rates estimated from comprising of two species formerly classified as internal N and P and nutrient uptake rates suggested Amphidinium and one novel species. Currently these a slower renewal of nutrients in B. scorpioides than in Keynote and Oral Papers 119

C. caespitosa. Photoacclimation experiments showed changes in the epiphytic microbial communities in that both species had maximum photosynthetic rate response to interacting local and global stressors. We (Pm) and photosynthetic efficiency (α) at 20-40 µmol used next generation sequencing (Illumina, Miseq) to photons m−2 s−1. Bostrychia scorpioides had higher characterise the epiphytic bacteria associated to the Pm, α, dark respiration rate and light compensation canopy-forming alga Cystoseira compressa, as this is point (Ec) than C. caespitosa at all acclimation irra- one of the most relevant canopy-forming algae in the diances. Growth-irradiance curves revealed a higher low intertidal shores around Italy. We also carried out Ec value for growth in B. scorpioides than for C. a factorial experiment to investigate the combined caespitosa, which agreed with the irradiance at their effects of nutrient enrichment (local anthropogenic respective distributional limits in the field. While light stressors) and heat stress (climate change-related clearly restricts the growth of B. scorpioides to the stressors) on the survival, growth and photosynthetic uppermost intertidal zone, it would not prevent C. rate of C. compressa and the diversity of associated caespitosa from growing at saturating irradiances. microbial communities. Results showed a significant However, C. caespitosa is absent at the upper inter- increase in OTU richness with increasing of algal tidal zone where that high light occurs. At the upper- surface age. Moreover, there was a clear difference most level of the intertidal, the longer periods without between the microbial composition associated with nutrient supply could limit the performance of C. macroalgae and that of the surrounding seawater. caespitosa to a certain extent, whereas B. scorpioides Finally, in situ experiment showed an effect of nutrient would be more able to cope with the reduced nutrient enrichment and heat stress on both photosynthetic availability given its greater independence on external activity and bacterial community composition. supply. Both species have distinct capacities for acquiring nutrients and different light requirements, which partially explains their intertidal zonation. MANTON.9 INVESTIGATING THE FEASIBILITY OF HIGH VALUE COMPOUND PRODUCTION IN MANTON.8 MICROALGAE BACTERIAL DIVERSITY CHANGES TO 1 Julie AZ Zedler SIMULATED LOCAL AND GLOBAL 1 ([email protected]), Doris Gangl ([email protected]. STRESSORS ON THE CANOPY-FORMING 2 uk), Björn Hamberger ([email protected]), Saul ALGA CYSTOSEIRA COMPRESSA 3 1 Purton ([email protected]) and Colin Robinson Francesco Paolo Mancuso1 (francesco.mancuso4 ([email protected]) @unibo.it), Olivier De Clerck2 (Olivier. [email protected]) and Laura Airoldi1 (laura.air 1School of Biosciences, University of Kent, [email protected]) Canterbury CT2 7NJ, United Kingdom; 2Department of Plant and Environmental Sciences, University of 1Dipartimento di Scienze Biologiche, Geologiche ed Copenhagen, Frederiksberg C DK-1871, Denmark Ambientali, University of bologna, Ravenna 48123, and 3Institute of Structural and Molecular Biology, Italy and 2Phycology Research Group and Center for University College London, London WC1E 6BT, Molecular Phylogenetics and Evolution, Ghent United Kingdom University, Ghent 9000, Belgium Microalgae have recently been shown to hold signifi- Canopy-forming brown algae provide structurally cant promise as a novel biotechnological production complex habitats to a variety of species, along tempe- platform. A commonly used model organism is the rate rocky coasts. This includes rich but understudied green microalga Chlamydomonas reinhardtii. microbial communities, triggered by availability of Previous studies have mainly focused on the produc- protected micro-niches and large amount of organic tion of recombinant proteins, but not much has been carbon. Canopy-forming algae are retracting world- done to investigate the feasibility of high value com- wide particularly in urban areas, where they tend to be pound production in microalgae. We want to explore replaced by low-lying, turf-forming algae. Recent the potential benefits and limitations of microalgae for works suggests that nutrient enrichment (typical of biotechnological applications. Terpenoids are a large many coastal regions) interact synergistically with class of high value natural products. They are an other local and global stressors accelerating this attractive target for engineering, as they often cannot shift, but the underlying causes of these effects are be synthesised chemically due to their complexity. To unknown. Epiphytic bacteria can functionally regulate date, these compounds usually are extracted from and support the productivity and the resilience of higher plants at low yields. Producing them in micro- macroalgae. Therefore, we hypothesised that the loss algae could be a sustainable and cost-effective alter- of canopy-forming algae might be mediated by native. In the algal cell, recombinantly expressed Keynote and Oral Papers 120 enzymes can use abundant precursor molecules for optimizing phototrophic cultivation of algal biomass. light-driven product formation. In a first proof-of-con- However, the maximum algal biomass one can cept study we used a recently developed low-cost achieve using phototrophically grown algae is chloroplast transformation protocol to express a 91 restricted by light or inorganic carbon availability, kDa bifunctional terpene synthase. This enzyme cata- and sometimes both. Therefore, other modes of grow- lyses the formation of a diterpene that can potentially ing algae such as heterotrophy and mixotrophy need be used as a precursor molecule for fragrance produc- to be investigated. We grew Scenedesmus sp. in tion. In this study we obtained homoplasmic transfor- complete darkness using molasses as the growth mants which produced promising amounts of medium and found that heterotrophy led to bigger recombinant protein. cells, faster growth rates and denser cultures as compared to phototrophically grown cultures. Moreover, MANTON.10 these heterotrophically grown cultures surprisingly retained their photosynthetic apparatus with similar USE OF HETEROTROPHY AND values in all the photosynthetic parameters measured. MIXOTROPHY FOR ALGAL BIOMASS Exposing molasses-grown cultures to light during the PRODUCTION late exponential phase further boosted growth rate and fi Manoj Kamalanathan (manoj.kamalanathan biomass production signi cantly. As a result, the @monash.edu), Ros Gleadow (ros.gleadow biomass obtained through this process (mixotrophy) @monash.edu) and John Beardall (John. is twice as large as with heterotrophically grown cul- [email protected]) tures and three times larger than with photosynthetically grown cultures. We also observed some School of Biological Sciences, Monash University, interesting changes in the photosynthetic apparatus Melbourne 3800, Australia under heterotrophic and mixotrophic conditions that allow the cells to keep their photosynthetic rates on Considerable research has been carried out on the par with photosynthetically grown cultures. potential for algal-derived biofuels, yet this has not Furthermore, calculations suggest that the molasses yet been made a commercial reality due to the high addition to growth media will only cost ~ 1 cent per cost and low biomass productivity of algal biofuels. liter. Overall, this study provides promising leads for a Research conducted so far has mainly focused on greener future.