Scientists scour global waters to test for plankton and ocean pollution

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Lorient (France) (AFP) – After a nearly two-year “Microbiome” mission around the world, scientists said on Saturday they had collected thousands of samples of marine microorganisms in a bid to better understand plankton and ocean pollution.

The study was carried out from the 33-year-old research schooner Tara, which this weekend returned to its home port of Lorient, on the west coast of France.

From Chile to Africa, via the Amazon and Antarctica, nearly 25,000 samples were taken on the 70,000 kilometer route.

“All of this data will be analyzed,” said Romain Trouble, director of the Tara Ocean Foundation, during a press conference.

“Within 18 months to two years, we will start to have the first findings from the mission,” he said.

At the base of the food chain, microorganisms were the “invisible people of the sea,” accounting for two-thirds of marine biomass, Trouble said.

“They capture atmospheric CO2 (carbon dioxide) and provide half of the oxygen we breathe.”

Trouble said the mission is trying to find out how it all works.

“How do all these marine viruses, bacteria, micro-algae manage to interact to produce oxygen?”

“And how will that change tomorrow with climate change and pollution?”

Tara’s team paid particular attention to the impact on the oceans of the Amazon River, which has a water flow of 200 million liters (53 million gallons) per second.

They wanted to test a theory that deforestation and the spread of agriculture have increased the release of nitro fertilizers, leading to an abundance of toxic algae along riverbanks and coasts, particularly in the Caribbean.

The 22-month odyssey also sought to trace the sources of plastic pollution at river mouths, understanding the distribution and types of materials involved.

The mission was Tara’s 12th global trip and involved 42 research institutes around the world.

Next spring, Tara goes in search of chemical pollution off the European coast.