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The Tara mission

Marine Life Survey

Sailing the oceans from September 2009 to 2012, an international team of researchers on board the schooner Tara will investigate the abundance and diversity of bacterial and planktonic life.

This September, the schooner Tara set sail from Lorient, France, for the Mediterranean, then the Persian Gulf, the Indian Ocean, and beyond. It is due to return at the end of 2012. “By then, it will have sailed across most of the world's seas and oceans,” says biologist Éric Karsenti, a CNRS researcher on temporary assignment to the European Molecular Biology Laboratory in Heidelberg, Germany, and co-director of the Tara Ocean expedition. “This voyage, roughly the equivalent to circling the globe twice, will have taken us through areas that are extremely varied in terms of biological resources, biodiversity, and human impact on the environment. Furthermore, the route lets us sail with prevailing winds, thus limiting our fossil fuel consumption.”
bateau tara

© F.Latreille/

Only 36 meters long, the Tara schooner is relatively small for an oceanographic vessel, and can therefore adapt to difficult sampling conditions.

The mission follows on from the Tara Arctic expedition, which had the schooner locked in Arctic pack ice, drifting with it for two years (and across a distance of 1800 km) to study climate change phenomena at high latitudes. Tara Ocean's mission is focused on understanding and assessing the impact of global warming–and the acidification of the oceans that accompanies it–on the life of marine micro-organisms.
It is exploring in particular the world of plankton, an ecosystem whose diversity and working mechanisms are poorly understood. As the ship sails on, the on-board instruments can collect a host of data from the surface all the way down to a depth of 1000 meters. These include physical, chemical, and biological measurements like temperature, salinity, pH, and biomass density of sea water, as well as carbon flux from the surface to the sea floor. But the planktonic organisms themselves are also picked up for research. The collected samples, ranging from protists (a group of unicellular organisms), to viruses, bacteria, microalgae, microcrustaceans, and larvae of various organisms, are then packaged on board and sent to the various laboratories taking part in the mission.
“Due to the ship's relatively small size, it can only host five scientists, but a large number of researchers from all over the world–especially colleagues from CNRS–are part of this project: oceanographers, biologists, geneticists, physicists, etc.,” adds Karsenti. Onboard imaging systems enable them to rapidly receive initial images of the organisms collected, which is likely to lead to the discovery of many new species.
carte tara

Roadmap for Tara, which will travel 150,000 km on four oceans and many seas, stopping in 50 countries.

The aim is also to improve our understanding of ocean-climate interactions, and to predict their evolution. “The seas and oceans produce half the oxygen we breathe and absorb 50% of overall CO2 emitted into the atmosphere, half of which stem from human activity. And if we know that these properties are mainly due to planktonic organisms, we still need more experimental data to understand and quantify how this 'biological carbon pump' works, and how climate change is affecting it. A major question for anyone trying to predict future climate change is to find out how these planktonic ecosystems will adapt to global warming and pollution,” Karsenti explains.
All the data gathered, with their GPS position, will be fed into an integrated public database, the Bio-Bank. This will create a reference for future research into climate change's effects on marine ecosystems and the ocean carbon pump. “And as Tara continues its journey, we will be able to draw up a 'functional map' of the oceans, which will be available online to help raise public awareness about these issues,” Karsenti concludes.

Marie Lescroart

Contacts :

Éric Karsenti,
EMBL, Heidelberg.
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