PrOtiSts EcologIcal bioDiversity in Tara-OceaNs – POSEIDON

The project POSEIDON ' PrOtiStan EcologIcal bioDiversity in Tara-OceaNs - is an important component of Tara-Oceans, the 3 year circum-global scientific expedition of the schooner Tara, co-organized by the CNRS/UPMC/ParisMuseum, the European Molecular Biology Laboratory (EMBL), and Tara-Expeditions. POSEIDON associates 3 French partners, the Station Biologique de Roscoff (CNRS/UPMC), GENOSCOPE, and the PME Tarawaka, and 2 self-funded international partners, the EMBL in Heidelberg and the University of British Columbia (UBC) in Canada. This consortium will combine their excellence in marine microbiology and eukaryotic ecology and evolution, high-throughput DNA sequencing and bioinformatics, state-of-the art microscopy screening techniques, and the logistics of organizing extended and high-profile ocean expeditions, to explore the biodiversity of arguably the least known but climatically most relevant compartment of the biosphere: open ocean unicellular eukaryotes (protists). We propose an innovative and highly integrative strategy to: (i) establish a nearly exhaustive inventory and archive of unicellular eukaryotic biodiversity of the global open oceanic photic zone (2 depths, 375 stations); (ii) assess, in 10 contrasting stations, the intrinsic complexity and structure of protistan morpho-genetic diversity covering the entire tree of eukaryotic life; (iii) correlate change in open ocean protist biodiversity (phenotypic and genotypic) with biogeography and the physico-chemical properties of marine waters, with an emphasis on ocean acidification; (iv) raise worldwide public awareness of the fragile beauty of marine protists and the critical role they play in the transfer of energy and matter through the biosphere, and thus the maintenance of its steady state. 375 stations from the world oceans will be sampled at 2 depths. Water will be sieved into 4 cell-size fractions (1-3/3-20/20-200/200-2000um), and stored under appropriate conditions for future DNA, RNA, and various high-throughput microscopy and chemical analyses. POSEIDON will coordinate distribution of these samples to a network of French and international collaborators, all of whom are recognized experts in the systematics of different eukaryotic 'super-groups', and will organize long-term sample archiving and analyses. The generation, for each of the 10 main POSEIDON stations, of ~6 million DNA sequences using 454-pyrosequencing will allow in depth exploration of group-specific nuclear, chloroplastic, and mitochondrial biodiversity tags with various levels of taxonomic resolution. The proposed dual genetic approach based on DNA and RNA tags will provide data on both diversity and relative abundance/activity of protist taxa, their organelles, and fundamental processes such as photosynthesis and respiration. Various techniques of high-throughput microscopy screening, the output of developmental and biomedical research at the EMBL, will be used (many for the first time) to analyze ultrastructural and cellular features of marine protists. Fluorescent In Situ Hybridization (FISH) protocols will be employed to directly link genetic and morphological exploration of protistan biodiversity. Finally, this integrative approach to protist morpho-genetic biodiversity will be statistically correlated to the physico-chemical properties of marine waters. POSEIDON will not only contribute to by far the largest census of marine protists ever undertaken (with likely the discovery of the largest ever set of new eukaryotic species), but also aims to identify the main eukaryotic players in global surface ocean biogeochemistry, to redefine morpho-genetic functional groups for realistic modeling of the Earth system, to assess patterns of genetic, phenotypic, and community adaptation to physico-chemical changes in ocean conditions (in particular to natural variations of carbonate chemistry and pH encompassing future scenarios of ocean acidification), and to address a suite of fundamental questions in microbial ecology and evolution. POSEIDON will stimulate exchange of techniques and ideas between dedicated molecular and cell biologists and biological oceanographers and ecologists. It will contribute to the largest world community database on marine unicellular eukaryotic biodiversity, a reference platform for current and future projects dealing with this biodiversity compartment. Last but not least, POSEIDON will generate thousands of new images and videos illustrating the exquisite beauty of pelagic protists along the 100,000 km of the Tara_Oceans cruise. These will serve as raw material to develop a series of documentary films, an itinerant photograph exhibition, educational packages for schools, an interactive web site, and a workshop/exhibition 'Design and nanotechnologies from the oceans' in 2012, all designed to inform our fellow citizens and politic leaders about the ecological, climatic, and economic importance of the seemingly invisible planktonic world.