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In Brest, I experienced cold water reefs due to global warming – 09/02/2022 at 13:41


The ship Thalassa, moored in the port of Brest, unloads pressurized buckets containing cold-water coral, August 31, 2022 (AFP/Sebastien SALOM-GOMIS)

Docked in the port of Brest, the Thalassa is unloading an unusual cargo: pressurized buckets containing cold-water corals, whose reaction to global warming will be examined by Ifremer scientists.

At dawn on Wednesday, scientists, sailors and technicians from the Sheriff 2022 Expedition (Characterization and Ecology of Cold-Water Coral Reefs) brought back these animals after fifteen days at sea, taken from a Natura 2000 classified canyon located at a depth of 800 meters and 12 hours. Navigation from the mainland in the Bay of Biscay.

“The impact of climate change on the growth of these corals” will be studied in Océanopolis as part of the Ardeco project, developed by Dominique Barthélémy, coordinator responsible for the living environment at this national center for scientific culture dedicated to cultivated oceans. Brest.

He notes that these ‘madrepora oculata’ corals will remain under pressure in equipment called the cliff box.

Cold-water coral, collected by Evermer researchers, aboard the ship Thalassa, on August 31, 2022 in Brest, western France (AFP/Sebastien SALOM-GOMIS)

Cold-water coral, collected by Evermer researchers, aboard the ship Thalassa, on August 31, 2022 in Brest, western France (AFP/Sebastien SALOM-GOMIS)

“Cold-water corals have an important functional role in the entire deep system because many species come to feed there, and they are carbon sinks,” explains Lenaick Menot, a benthic ecologist (the study of the ocean floor) at Ifremer. and co-chair of the campaign.

“They are threatened by fishing (note trawling editor) and possibly by climate change,” he worries.

Its scientific value is offset only by the exceptional precautions the staff take to empty the fifteen buckets that contain the reefs.

– Carbon dioxide acidifies the seas –

According to the scientist, “corals will be the first to suffer,” according to the warming and acidification of the ocean.

Evermer Scientist restores coral reefs in cold water on board the ship Thalassa, August 31, 2022 in Brest (AFP / Sebastien Salom-Gomis)

Evermer Scientist restores coral reefs in cold water on board the ship Thalassa, August 31, 2022 in Brest (AFP / Sebastien Salom-Gomis)

“The ocean is a trap for atmospheric carbon dioxide that increases the acidity of seawater, and prevents corals from excreting their calcareous skeleton” which also tends to melt.

To read the future of corals, the first step was to imagine sampling at a depth of 1,000 metres, bringing them to the surface while maintaining the pressure and temperature of their original environment.

For this purpose, Ifremer used the Victor submarine, a gem of technology that weighs nearly 5 tons and can descend to 6000 metres.

“The most complicated thing was to fight the current and make sure the ballast and cables didn’t rub against the cliff,” remembers Luke Tails, one of the pilots and technical director at Victor.

A member of Ifremer in front of the robot Victor, who can descend up to 6000 metres, on the Thalassa boat, on August 31, 2022 in Brest (AFP / Sebastien SALOM-GOMIS)

A member of Ifremer in front of the robot Victor, who can descend up to 6000 metres, on the Thalassa boat, on August 31, 2022 in Brest (AFP / Sebastien SALOM-GOMIS)

Capable of withstanding 600 bar of pressure (i.e. 600 kg per square centimeter), it is routed from the surface by technicians connected to the submarine by cable.

The robot’s mechanical arms, operated remotely using cameras, grab the corals to place them in small pressurized aquariums placed in a basket, in order to keep the reefs at 100 bar and 10 degrees regardless of outside conditions.

world first.

– survival under threat –

The corals, protected in Océanopolis, will be taken from scraps to be placed in compact boxes the size of a small fire extinguisher, as well as reproduce the current and food they are accustomed to.

Evremir Scientist transports cold-water corals in pressurized boxes, unloaded from a Thalassa boat, on August 31, 2022 in Brest (AFP/Sebastien SALOM-GOMIS)

Evremir Scientist transports cold-water corals in pressurized boxes, unloaded from a Thalassa boat, on August 31, 2022 in Brest (AFP/Sebastien Salom-Gomis)

Dominique Barthelemy confirms that “one of these boxes will be shown to the public,” specifying that “this is part of the public outreach missions of Océanopolis that wish to encourage its visitors to better protect the environment.”

“We will subject them to two climate change scenarios, a temperature increase of 2 degrees, and water acidification of 0.2 units, which the IPCC models predict by 2100. If they want to dive to find the cold water they need, it will probably be,” concludes Mr. Minot. Their survival is threatened by global warming.”

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