Abstract book VI International Rhodolith Workshop Roscoff, France 25-29 June 2018 Table of contents Taxonomy 6 Molecular systematics: toward understanding the diversity of Corallinophyci- dae, Viviana Pena...................................7 Simplified coralline specimens' DNA preparation, mini barcoding & HRM analysis targeting a short psbA section, Marc Angl`esD'auriac [et al.]...........8 Reassessment of Lithophyllum kotschyanum and L. okamurae in the North-Western Pacific Ocean, Aki Kato [et al.]............................9 Phymatolithopsis gen. nov. (Hapalidiaceae, Rhodophyta) based on molecular and morphological evidence, So Young Jeong [et al.]................ 10 Morpho-anatomical descriptions and DNA sequencing of the species of the genus Porolithon occurring in the Great Barrier Reef, Alexandra Ord´o~nez[et al.].... 11 Ecophysiology 12 How do rhodoliths get their energy?, Laurie Hofmann............... 13 Effect of seawater carbonate chemistry and other environmental drivers on the calcification physiology of two rhodoliths, Steeve Comeau [et al.]......... 14 Short- and long-term effects of high CO2 on the photosynthesis and calcification of the free-living coralline algae Phymatolithon lusitanicum, Jo~aoSilva [et al.].. 15 Physiological responses of tropical (Lithophyllum pygmaeum) and temperate (Coral- lina officinalis) branching coralline algae to future climate change conditions, Bon- nie Lewis [et al.].................................... 16 Role of evolutionary history in the responses of tropical crustose coralline algae to ocean acidification, Guillermo Diaz-Pulido [et al.]................ 17 1 Coralline algal recruits gain tolerance to ocean acidification over successive gen- erations of exposure, Christopher E. Cornwall [et al.]................ 18 Rhodolith communities in a changing ocean: species-specific responses of Brazil- ian subtropical rhodoliths to global and local stressors, Nadine Schubert [et al.]. 19 Maerl bed community physiology is impacted by elevated CO2, Heidi Burdett [et al.]............................................ 20 Relative importance of temperature and irradiance on rhodolith (Lithothamnion glaciale) growth, David B´elanger[et al.]....................... 21 Causes and consequences of rhodolith bed primary productivity: when descriptive ecology meets physiology, Vanessa Carvalho [et al.]................. 22 CaCO3 production rate estimates of a southeastern Newfoundland rhodolith bed, Laura Teed [et al.]................................ 23 Community production and calcification in a sub-arctic rhodolith beds in north- western Iceland, Karl Gunnarsson [et al.]....................... 24 Geology and Paleontology 25 Coralline algae in space and time: A palaeontological perspective, Julio Aguirre. 26 How corallines calcify, build reefs and evolution of biomineralisation, Merinda Nash [et al.]....................................... 27 Rhodoliths as pCO records: acidification in the pre-instrumental era, Ellen Mac- donald [et al.]...................................... 28 Sclerochronological study in Saint-Pierre et Miquelon (Northwest Atlantic): A new method to explore growth patterns of Clathromorphum compactum for pa- leoenvironmental reconstruction, Valentin Siebert [et al.].............. 29 Modelling maerl habitat dynamics in response to increased storminess, Siddhi Joshi [et al.]....................................... 30 Coralline algal habitats in a late Miocene platform in Sierra de G´ador,Almer´ıa, SE Spain, Fernando Sola [et al.]............................ 31 Coralline algae in Pleistocene reefs in the Danakil Depression (Afar Triangle, Ethiopia), Juan Braga [et al.]............................. 32 Ecology 33 2 Rhodolith beds as blue carbon repositories, Nicholas A. Kamenos......... 34 Spatio-temporal study of the diversification of coralline species (Rhodophyta), Line Le Gall [et al.]..................................... 35 Deep-water rhodoliths off Pico Island, Azores (NE Atlantic), Ana Cristina Re- belo [et al.]....................................... 36 Use of high-resolution 3D imaging to identify the light-harvesting capacity of coralline algal carbonate nodules, Beauregard Marsh [et al.]............ 37 What have coralline red algae inside their cells?, Paulo Horta [et al.]....... 38 Coralline algal skeletal mineralogy affects grazer impacts, Sophie Mccoy [et al.]. 39 An experimental comparison of bacterial diversity and function in the maerl Lithothamnion glaciale Kjellman (Corallinales, Rhodophyta) from southwestern Greenland, Kathryn Schoenrock [et al.]........................ 40 Assessment of maerl beds structure and vitality by image analyses across a dredge- fishing pressure gradient in the Bay of Brest (Brittany, France), Guillaume Bernard [et al.]............................................ 41 More species, more functions? The influence of maerl beds on polychaetes assem- blages, Aur´elienBoy´e[et al.]............................. 42 Macroinvertebrates associated with the rhodolith beds from euphotic and mesophotic zones in the South Atlantic: Fernando de Noronha Archipelago, Brazil, Priscila Veras [et al.]....................................... 43 The abundant and diverse meiofauna from maerl beds: a first insight from the Bay of Brest (Brittany), Federica Rebecchi [et al.]................. 44 Conservation & Management 45 Maerl beds of the NE Atlantic, faunal diversity and conservation concerns, Jason Hall-Spencer...................................... 46 Rhodolith Taxa: Agents of Benthic Community Change on Tropical Pacific Reefs?, Tom Schils [et al.]...................................... 47 Heterogeneity rather than size determines faunal colonization of discrete habi- tat units: a case study with rhodolith-associated macrofauna, Francisco Otero Ferrer [et al.]...................................... 48 3 Assessing the relative habitat value of maerl compared to adjacent sediment habi- tats., Samantha Blampied [et al.]........................... 49 Depth determines structure and functioning of rhodolith habitats in Central- Eastern Atlantic, Francisco Otero Ferrer [et al.]................... 50 Brazilian rhodoliths - a world heritage under threat, Paulo Horta [et al.]..... 51 Changes in the Milford Haven maerl bed between 2005 and 2016, Francis Bunker 52 Macrofauna community shifts in fished maerl beds in the Bay of Brest, France, Michael Pantalos [et al.]..................................... 53 Workshop 54 Global status of rhodolith (maerl) research: looking back to move forward, Diana L. Steller [et al.].................................... 55 The whole is greater than the sum of its parts: Rhodolith Ecosystem Ecology and COnservation Network (REECON), Patrick Gagnon................ 56 Rhodolith formation in the deep water off Marettimo, Egadi Islands, Sicily, Daniela Basso [et al.]...................................... 57 Maerl Fossil, a biomarker of paleoenvironmental fluctuations for the past 2000 years in the Bay of Brest, Axel Ehrhold, [et al.]................... 58 Poster session 59 Evidence of Coralline White Patch Disease in a rhodolith bed of the Egadi Is- lands, Daniela Basso [et al.].............................. 60 Quantifying the contribution of coralline species in rhodoliths as a tool for pale- obathymetric reconstructions, Daniela Basso [et al.]................. 61 Insight in coralline composition and main morphotypes of Tuscan Archipelago rhodolith beds (Tyrrhenian Sea), Enrico Cecchi [et al.]............... 62 Composition and heterogeneity of Mediterranean rhodolith beds: the case of Apu- lia (Italy), Giovanni Chimenti [et al.]......................... 63 Mapping subtropical and tropical rhodolith seabeds using Side Scan Sonar tech- nology, Marcial Cosme [et al.]............................. 64 4 Ultra-morphology and phylogeny of Phymatolithon purpureum and P. laevigatum (Hapalidiaceae, Rhodophyta) based on comparison of type materials, So Young Jeong [et al.]...................................... 65 Ultra-morphology of Lithothamnion japonicum (Hapalidiaceae, Rhodophyta): A little-known species from the Northwest Pacific, So Young Jeong [et al.]..... 66 May grazers influence the response of coralline algae to ocean acidification and warming?, Erwann Legrand [et al.].......................... 67 Weak latitudinal but strong local effects in Phymatolithon calcareum are shaping the genetic structure of Atlantic European maerl beds, Viviana Pena [et al.]... 68 Combined effects of global climate changes and nutrient enrichment on the phys- iology of three temperate maerl species, Zujaila Qui Minet [et al.]......... 69 Characterization of different rhodolith beds off the Campania Coast (Tyrrhenian Sea), Francesco Rendina [et al.]............................ 70 Norways hidden marine biodiversity: the hunt for cryptic species within the coralline algae, Eli Rinde [et al.]............................ 71 Vermetid gastropods as associated fauna in rhodolith beds along the Brazilian coast, Paula Spotorno-Oliveira [et al.]........................ 72 Deep-water coralline algal rhodoliths forming an extensive pavement on the Brazil- ian continental shelf, Frederico T^amega[et al.]................... 73 Author Index 73 List of participants 77 Financial support and sponsoring 80 5 Taxonomy 6 Molecular systematics: toward understanding the diversity of Corallinophycidae Viviana Pena ∗ 2;1 2 Institut de Syst´ematique, Evolution,´ Biodiversit´e(ISYEB, UMR 7205 CNRS MNHN UPMC EPHE). { Mus´eumNational d'Histoire Naturelle (MNHN) { France 1 BioCost Research Group, Universidade da Coru~na,A Coru~na{