The Tara Oceans expedition, co-directed by Eric Karsenti (CNRS researcher) and Etienne Bourgois, sails on all the seas to study marine plankton ecosystems (plankton plays an essential role in the life of the planet implementing, for example, half of total photosynthesis). From its departure from Lorient on 5 September 2009 and its return on 30 April 2012, the schooner Tara implemented 154 scientific stations in order to collect samples for laboratory analysis. Some 20 additional stations are being implemented in the Arctic Ocean. The samples are both organism collections and sets of physicochemical data acquired with a view to characterizing the environment in which the organisms exist.
Compared to other metagenomic programs, the principal innovation of Tara Oceans resides in its holistic approach. It is no longer a question of elucidating a particular group such as bacteria, viruses or eukaryotic organisms, but of describing them all at the same time. There are numerous modes of interactions between species, such as symbiosis, parasitism and competition, which explain the dynamics of the microorganism communities and can only be taken into account by studying all the players. The initial results obtained indicate that the genetic diversity of those communities has been under-estimated overall. Tens or even hundreds of thousands of totally unknown species have thus been revealed, transforming our image of microorganism biodiversity. Moreover, high-throughput imaging data on the organisms collected are currently being acquired. They should enable us to conduct genetic and morphological correlation with the aim of further elucidating the incredible diversity of plankton life forms.
Ctenophore.
Credit Christian
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 Jellyfish and amphipod
Credit Christian Sardet
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The distribution of plankton microorganisms in the oceans is not random. The distribution is in part determined by the environment, latitude, currents and interactions between species. Tara Oceans collects data enabling the characterization of species, their interactions and their genetics not only for interpretation of their biology but also in order to build models predicting their organization in ecosystems and the geographic distribution of those ecosystems. The models will contribute to enhancing prediction of how marine life will evolve as a function of climate change while further elucidating the cycle of basic chemicals in the oceans (carbon, nitrogen, oxygen, etc.) and thus the overall regulation of the world's climate. |
Learn more about Tara Oceans project : http://oceans.taraexpeditions.org/