J. Phycol. 47, S1–S98 (2011) Ó 2011 Phycological Society of America DOI: 10.1111/j.1529-8817.2011.01050.x ABSTRACTS SYMPOSIA TALKS studying marine picoeukaryotes and resulting insights on their evolution, diversity and physiology will be discussed. THE EVOLUTION OF PROTISTS AND THEIR ORGANELLES: NEW INSIGHTS FROM THE FRONTIERS OF GENOMICS ECOLOGICAL ASPECTS OF NITROGEN- Roger, Andrew FIXING CYANOBACTERIA ILLUMINATED BY Centre for Comparative Genomics and Evolutionary GENOMICS AND METAGENOMICS Bioinformatics, Department of Biochemistry and Molecular Zehr, J. P. Biology, Dalhousie University University of California, Santa Cruz, USA, [email protected] The availability of inexpensive genome and tran- Tripp, H. J. scriptome sequencing capacity has furnished insights University of California, Santa Cruz, USA, into the biology, biochemistry, evolutionary relation- [email protected] ships and dynamics of protistan genomes at an Hilton, J. unprecedented rate. From these data, large concate- University of California, Santa Cruz, USA, nated data sets of conserved protein genes have been [email protected] assembled and phylogenomic analyses are converging Moisander, P. H., University of Massachusetts, USA, to a stable picture of the inter-relationships of the [email protected] major eukaryotic super-groups. At the same time, Foster, R., Max Planck Institute for Marine Microbiology, comparative assessments of gene contents of diverse Germany, [email protected] microbial eukaryote genomes are allowing us to tease apart the relative impact of primary and secondary Nitrogen is a key nutrient limiting the productivity endosymbiotic organelle-based gene transfer versus of the oceans. Nitrogen fixation is an important lateral gene transfer in shaping the biochemical prop- source of nitrogen to the surface waters of oligo- erties of these organisms and their subcellular com- trophic oceans and was believed to be primarily due partments. In this presentation I will provide an to the marine cyanobacterium trichodesmium, until the example of how newly acquired genomic and tran- discovery of nitrogenase genes associated with other scriptomic data from non-photosynthetic protists have bacteria and cyanobacteria. The application of geno- changed our understanding of: (1) the major super- mic and metagenomic approaches has unveiled groups of eukaryotes, (2) the true biochemical unusual aspects of the metabolism of free-living and spectrum of mitochondrial function in free-living and symbiotic cyanobacteria. Unicellular cyanobacteria parasitic protists and (3) the genome evolutionary lacking basic metabolic features such as photosystem mechanisms by which protists adapt to new environ- II and the TCA cycle suggest that yet more symbioses ments. are yet to be discovered, and these organisms appear to have a wider global distribution than other nitro- gen-fixing cyanobacteria. Filamentous cyanobacteria in symbiosis also have unusual metabolic deletions. INTEGRATED APPROACHES TO THE These findings, in concert with biogeographic distri- ECOLOGY OF WILD AND CULTURED bution information suggest that nitrogen-fixation in PICOEUKARYOTES the oceans by marine cyanobacteria is much more Worden, Alexandra Z. complex than previously believed. Monterey Bay Research Institute Half of global primary production is performed by photosynthetic marine organisms, including a diverse array of algae. Among these, algae are tiny unicellular COMPARATIVE GENOMICS OF MARINE eukaryotes referred to as ‘‘picoeukaryotes’’. Although DIATOMS picoeukaryotic taxa such as the prasinophyte Micro- Armbrust, Virginia monas have been studied since the 1950’s, others are University of Washington, [email protected] still being discovered and many remain uncultured. Integrated genomic analyses that involve working with About one-fifth of the photosynthesis on Earth is both cultured isolates and ‘‘wild’’ uncultured popula- carried out by marine diatoms. Because of their tions are a powerful way to investigate these impor- important role in the global cycling of carbon, it is tant primary producers. Here, new approaches for critical to understand how these organisms will S1 S2 ABSTRACTS respond to the changing conditions of the world’s oceans. I will describe ways that comparative genom- THE COMBINED EFFECTS OF OCEAN ics can be used to develop new insights into both the ACIDIFICATION, MIXING, AND RESPIRATION evolution and ecology of diatoms. At least four whole ON PH AND CARBONATE SATURATION IN AN genome sequences are currently (or soon will be) URBANIZED ESTUARY available for marine diatoms, with the number of Feely, R. A. available diatom EST sequences increasing rapidly. I Pacific Marine Environmental Laboratory, USA, will provide examples of new approaches to under- [email protected] standing genetic diversity and biogeography by com- Alin, S. paring whole genome sequences derived from six Pacific Marine Environmental Laboratory, USA, strains of the model centric diatom, Thalassiosira [email protected] pseudonana isolated from different oceans. I will also Sabine, C. L. describe use of transcriptional analysis of both labora- Pacific Marine Environmental Laboratory, USA, tory isolates and field populations to understand the [email protected] response of diatom communities to environmental Newton, J. change. University of Washington, USA, [email protected] In order to study the combined effects of ocean acidification and other natural and anthropogenic processes on Puget Sound waters, we made inorganic carbon measurements in this estuary on two survey cruises in February and August of 2008. Observed pH and aragonite saturation state values in surface and subsurface waters were substantially lower in parts of THE CHONDRUS CRISPUS GENOME Puget Sound than would be expected from anthropo- Collen, Jonas genic carbon dioxide (CO2) uptake alone. We esti- Station Biologique de Roscoff mate that ocean acidification can account for 24–49% of the pH decrease in the deep waters of the Hood The red seaweeds represent the last large group Canal sub-basin of Puget Sound relative to estimated of advanced multicellular organisms without a pre-industrial values. The remaining change in pH sequenced genome and this lack of knowledge has between when seawater enters the sound and when it been a major obstacle in studies of red algal biology. reaches this deep basin results from remineralization We therefore decided to sequence the genome of of organic matter due to natural or anthropogenically the florideophyte Chondrus crispus (Irish moss), a stimulated respiration processes within Puget Sound. common seaweed with a long research history found Over time, however, the relative impact of ocean acid- on rocky shores on both sides of the Northern ification could increase significantly, accounting for Atlantic Ocean. The genome project is a collabora- 49–82% of the pH decrease in subsurface waters for a tion between an international consortium and the doubling of atmospheric CO2. These changes may French sequencing agency Genoscope. It is based on have profound impacts on the Puget Sound ecosys- a 14-fold sequence coverage and transcriptional data tem over the next several decades. of a gametophyte of Chondrus. A combination of automatic and expert annotation of the 105 Mbp genome has demonstrated approximately 9,500 pro- tein coding genes, of which a large proportion have ACIDIFICATION AND WARMING IN THE unknown functions. The genome is characterised by RESPONSE OF MARINE PHYTOPLANKTON TO gene-dense regions surrounded by repeat-rich blocks. ENVIRONMENTAL CHANGE The genes are compact with only 0.2 introns per Raven, John gene of limited size and short flanking untranslated University of Dundee, [email protected] regions. The genome is characterised by a low redundancy and small gene families, for example Additional atmospheric carbon dioxide increases concerning ribosomal proteins and enzymes involved the carbon dioxide concentration in the ocean, with in floridean starch metabolism. Other notable fea- an increase in dissolved carbon dioxide and bicarbon- tures of the genome include a large number of ate and a decrease in carbonate and pH. These genes involved in halogen metabolism, including 35 changes frequently decrease the calcium carbonate peroxidases and several dehalogenases. We anticipate content of calcification of calcified phytoplankton, that the sequencing and analysis of this genome as and either have no effect on, or sometimes com- well as the creation of a large transcriptomic monly increase, the growth rate of phytoplankton resource will establish Chondrus crispus as a relevant under otherwise optimal conditions. Warming has model organism for red macroalgae. direct effects on phytoplankton growth, and also ABSTRACTS S3 causes shoaling of the thermocline with increased mean photosynthetically active radiation incident on WHO’S NEW IN THE NEIGHBORHOOD? cells and decreases phosphorus and combined nitro- CHANGING SEAWEED BIODIVERSITY AND gen inputs to the upper mixed layer from the deeper ECOSYSTEM FUNCTION ocean. Combined nitrogen input is also decreased by Williams, Susan L. deoxygenated zones forming below the thermocline University of California, Davis, Bodega Marine Laboratory, when there is a decrease in the downwelled oxygen [email protected] flux relative to the sinking organic particle flux, increasing denitrification. These changes in nutrient Seaweed biodiversity is changing in ecological time and light availability increase photoplankton produc- due to shifts