A tour of Europe from Tallinn to Athens: the scientific schooner Tara cast off from Lorient (western France) on Sunday for a journey of more than 25,000 km intended to better understand the impact of human pollution on the invisible world of the ocean.
The ship designed by explorer Jean-Louis Etienne left its home port to the sound of the bagad and to the applause of a large crowd, who had come to cheer these researcher-navigators.
"The beauty of this expedition is that we don't know what we're going to find," smiles Colomban de Vargas, scientific director of the mission, leaning on the deck of the laboratory boat.
According to him, it is a question of studying "the invisible biodiversity at the land-sea interface and on a European scale" in order to "complete the great fresco of the ocean" started fifteen years ago by Tara.
During its previous expeditions, the scientific schooner has in fact already taken hundreds of samples of marine micro-organisms (viruses, bacteria, prostites, animals, etc.), mainly on the high seas. It was less interested in coastal ecosystems, "which are very different and very rich", adds the researcher.
The originality of this journey, passing through the Atlantic, the English Channel, the North Sea, the Baltic and the Mediterranean, is also due to the fact that it is part of a broader mission called TREC ("Crossing the European coasts ").
A mission that will mobilize several hundred researchers until July 2024, under the aegis of the European laboratory EMBL (European Molecular Biology Laboratory), a kind of CERN of biology, based in Heidelberg in Germany.
Because, beyond the exploration of biodiversity, it will also be a question of studying how pollutants (pesticides, drugs, chemicals, etc.) interact with invisible biodiversity.
"One of the objectives is to map the various pollutants in coastal waters, and to see how this influences microbial diversity", explains Flora Vincent, laboratory director at EMBL.
On imaginary lines along the European coasts, the researchers will carry out systematic sampling from land to sea: in soil, in sediments, on marine and terrestrial aerosols, in coastal waters and at sea. will have 120 coastal sampling sites, in 46 regions of 22 European countries between 2023 and 2024.
"We know that at very low doses, we observe very great effects on the ability of organisms to develop, to divide, to survive", remarks Flora Vincent. "Thus, in a field, a molecule that blocks photosynthesis will be used to prevent weeds from growing. Sometimes these chemical molecules will also impact micro-algae, which produce 50% of the oxygen each year."
EMBL researchers will thus follow Tara's journey on land, with vans transformed into mini-laboratories, but also a semi-trailer transporting scientific research tools (microscopes, high-pressure freezer).
In terms of means, "it's monumental", underlines Flora Vincent. EMBL researchers are rather reputed to be "laboratory rats" but "there is a real awareness of the need to go and see what is happening in the natural environment", says the specialist researcher in environmental research.
During the presentation of the mission in March, Edith Heard, the director general of EMBL, had compared the expedition to that carried out in the 19th century by Charles Darwin, father of the theory of evolution, on the ship Beagle. "I think it will give rise to lots of discoveries" or even "perhaps even new theories", had launched the scientist.
During her last expedition, which ended in mid-October 2022, Tara had traveled 70,000 km around the globe for nearly two years, taking thousands of samples of microorganisms whose analysis should make it possible to better understand the functioning of ocean plankton.
02/04/2023 19:08:40 - Lorient (AFP) - © 2023 AFP
