Noémie Coulon, Voice of the Ocean

Her initial findings cameas “a bombshell” to the marine science community, says Noémie Coulon. In her dissertation, defended in late 2024 at the National Museum of Natural History (MNHN), the marine ecologist highlights the alarming effects of climate change on sharks and rays in Europe—species previously considered resilient.“There was a relative scientific consensus that these species, which are hundreds of millions of years old and have survived numerous climate crises, would be able to weather this new crisis.”Several findings show that this is not the case.

The young researcher first highlighted the northward migration of rays and sharks driven by climate change. To reach this conclusion, she analyzed catch data from scientific bottom-trawl surveys conducted in European seas. A 25-year time series covering nine fished species provided her with a valuable dataset.“I found six species present in the southern North Sea, even though they had never been observed there before, even when looking back through historical records throughout the 20th century.”

89% mortality at +4°C

Even more concerning is the impact of warming and water acidification on the reproduction of these large predators. Experiments raising small dogfish eggs in tanks show that, when water temperature is varied, while a 2°C increase causes no issues, mortality rates soar to 89% at 4°C! Beyond the eggs,“there could be impacts at every level: gamete production, the signals needed for males and females to find each other, sperm storage by females…,” adds Noémie Coulon. These are very concerning results, confirmed by other studies on the greater frilled bat, which is more sensitive to environmental changes and shows a potential population collapse at a 4°C increase.”

France is home to more than a hundred species of sharks and rays,“so these issues are not trivial,” emphasizes the young researcher, who highlights the unique and irreplaceable roles of these large predators, which are already threatened by fishing. In addition to their position at the top of the food chain, these species play a role in the carbon cycle by making daily migrations into the depths.“Some burrowing rays stir up the sand, thereby revitalizing the ecosystem by suspending particles and preventing anoxia in the environment,” adds the researcher, who makes no secret of her delight in working with these large fish—a holy grail for young marine ecologists.

“Engagement Strategy”

As a postdoctoral researcher at the Marbec laboratory through 2027, Noémie Coulon is currently contributing to ongoing fish monitoring efforts in the marine protected areas of the French Mediterranean. Using diving observations and environmental DNA sampling—two non-invasive approaches—she is focusing in particular on modeling the characterization of fish in these habitats.

But for now, she is focusing on another task: championing the cause of marine species by sharing the scientific findings of the 2,000 researchers participating in the One Ocean Science Congress. As a winner of the 2024 L’Oréal-UNESCO For Women in Science Young Talent Award, Noémie Coulon is one of nine “ECOP insiders”—or “Early Career Ocean Professionals”—embedded in the congress taking place ahead of the UNOC in Nice in early June. Each has been selected to widely share this information with the nine major language communities: Mandarin, English, Spanish, Arabic, Hindi, Portuguese, French, Russian, and German.“There is both a need to raise public awareness and a strategy to mobilize support on these issues in order to influence the negotiations that will follow,” the scientist argues.