[LUM#18] Arctic Mission

[LUM Magazine] - Published on May 2, 2023 in Science-Society

To determine whether the distribution areas of marine fish are changing with climate change, Loïc Sanchez sailed across the Baffin Sea, collecting environmental DNA samples along the way.

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2,000 kilometers across the Baffin Sea to connect the Inuit community of Grise Fiord with Saint Pierre and Miquelon. This is the extraordinary journey undertaken by Loïc Sanchez aboard Vagabond, a 15-meter sailboat commanded by seasoned explorer Eric Brossier.

A unique experience for the young doctoral student at the Marbec laboratory¹. His mission? To predict changes in the distribution areas of marine fish species. "We want to know whether, with climate change, species that were previously found elsewhere are now found in this area, " explains Loïc Sanchez. Although scientists already have a wealth of data at their disposal, the young researcher points to some "gaps in the data."

"There are areas that are severely under-sampled, including the poles, yet these are crucial data because the effects of climate change are particularly intense there. " And most of the data available to scientists so far comes from direct observations made while diving. This method
, has its limitations: "For example, you might miss species that are very shy and hide from divers, or species that are too small to be easily observed," explains Loïc Sanchez.

To track down these elusive creatures and fill in the gaps in the database, Loïc Sanchez uses environmental DNA (eDNA) technology, which involves filtering water samples to recover DNA left behind by living organisms. This DNA is then compared with data from a reference database to identify the species to which it belongs. "This will enable us to assess the contribution of environmental DNA to the detection of additional species, " explains Loïc Sanchez.

The doctoral student took around thirty samples throughout his journey, "data that is worth its weight in gold because until now there had never been any sampling there." Back on land, they are sent for analysis to the start-up Spygen to reveal which species inhabit the waters of this sea bordering the Arctic Ocean. "This information will enable us to predict changes in fish
tribution areas according to several climate change scenarios."