THE DEPTHS OF THE OCEAN: A REFUGE FOR BIODIVERSITY?

In response to last summer’s unprecedented mass mortality episode, scientists are seeking to understand how Mediterranean red gorgonians and their ecosystems can survive in the ocean twilight zone. For these species, the ocean could act as a thermal shield and its depths could constitute a salutary refuge. Beyond 50 meters depth, gorgonians seem to be preserved. For these species, which are sensitive to temperature fluctuations, the depths, which are less affected by the anomalies linked to global warming, could be a real climate refuge. To find the answers, UNESCO and the Mission 1 OCEAN have launched a scientific exploration mission in collaboration with the?LECOB x CNRS - Centre national de la recherche scientifique. As we explore these depths, shipwrecks serve as incredible natural laboratories. By pinpointing the date of these wreckages, we can determine the exact age of gorgonian colonies that grow on their hulls.

AN ALARMING OBSERVATION?

Red gorgonians are an iconic species of coral, native to the Mediterranean. Like a network of trees, these animals are the building block of rich underwater forests. They play an essential role in marine biodiversity by providing valuable services to other species.

Gorgonians are not only a source of food, but also act as a nursery and a place of shelter.

In 2022, summer temperatures have been particularly high. In the Northern Mediterranean, this resulted in an episode of unprecedented mass decimation.?

The results are alarming: between 0 and 30 meters of depth, almost all the gorgonians species died within just a few days.

According to climate projections, these disturbances will become increasingly frequent. In the short term, the gorgonian populations could be seriously threatened, and along with all the ecosystems that depend on them.

THE OCEAN TWILIGHT ZONE: A REFUGE FOR BIODIVERSITY?

But beneath this twilight zone, the landscape changes dramatically and there is reason for hope. Here, at a depth of 50 meters, the gorgonians are perfectly intact and in good health. Could these deeper waters become an ultimate haven for the Mediterranean gorgonians??

"The reaction of the Gorgonians in the Mediterranean reflects what is happening across our planet. Like the Amazonian forest, the underwater animal forests are disappearing little by little, with consequences just as dramatic. For thousands of living beings, these forests are both a protective habitat and a food source and their disappearance inevitably leads to a loss of biodiversity."

Alexis Rosenfeld , Explorer and Photographer from Mission 1 OCEAN .

This will teach us how long it takes for gorgonians to develop self-sufficiently, cut off from the surface by a twilight zone made uninhabitable by global warming.

“The mortality of gorgonians is probably the last alarm signal with regards to the ecological crisis we are going through”

Lorenzo Bramanti , CNRS - LECOB researcher

But a wreck is not eternal. Eventually, these laboratories are doomed to disappear. So exploring them is both an ecological and a scientific emergency.?

Learn more: https://on.unesco.org/3ueeK2H

1 OCEAN

1 OCEAN is an exploration project led by the photographer and explorer Alexis ROSENFELD with UNESCO and the 1 OCEAN Foundation under the aegis of the CNRS Foundation. The aim of the 1 OCEAN Foundation is to explore and document the seabed, by supporting scientific research missions, in order to better understand and protect the Ocean, an exceptional common good.

UNESCO

Aware of the challenges related to the preservation of the Ocean, the United Nations has proclaimed the Ocean Decade (2021-2030). This initiative aims to mobilise the scientific community, political decision-makers, companies and civil society around the Ocean. For 10 years, UNESCO will accompany Alexis ROSENFELD and the 1 OCEAN Foundation in its exploration missions.

CNRS FOUNDATION

The purpose of the CNRS Foundation is to contribute directly or indirectly to the development and promotion of the CNRS, in all areas corresponding to its missions, as well as scientific and technological research, in France and abroad.

LECOB - CNRS

The Laboratory of Eco-geochemistry of Benthic Environments (LECOB) is a laboratory of the Oceanographic Observatory of Banyuls (OOB), a joint research unit (UMR) associated with the CNRS and Sorbonne University. The research activity of LECOB is focused on the study of marine biodiversity, ecology, resources and conservation, with a particular emphasis on benthic ecosystems.

This Mission is carried out with the support of: UNESCO , 索尼 , CNRS , Fondation de la Mer,?Ministères écologie énergie Territoires