It’s a setting that Olivier Bianchimani has seen thousands of times in the twenty years he’s been living here. As usual, the boat anchored in this paradise-like place, off the coast of Île Maïre, in the heart of the Calanques National Park, and turned its back on the Bonne Mère de Marseille. But underwater, paradise bathed in light becomes hell, under the eyes of a devastated Olivier Bianchimani. The director of the Septentrion Environnement association is the first to go back to the Caveman. The bottles still on his back, Olivier Bianchimani remains stunned. While he is unequipped, the diver, in shock, repeats, as if to better realize: “It’s devastated. It’s incredible. I have never seen that. It’s catastrophic. »
His colleague Tristan Estaque, scientific diver within the association, in turn takes his head out of the water. “It’s hot, huh?” launches Olivier Bianchimani, dazed. Everything burned. It’s as if you were walking in a beautiful forest, of which only the leaves and the trunk remain today. A ghost forest. “A massacre, breathes Tristan Estaque. A big massacre. Before, there was a wall of gorgonians. And everything is dead. It has nothing more to do. “Damn…” Olivier breathes out. The victims of this massive massacre are indeed the seabed, and more particularly the gorgonians, this red-colored coral emblematic of the fauna of the Mediterranean. Yesterday legion in the funds of the national park of the creeks, this animal, very sensitive to high heat, massively and suddenly disappeared off the coast of Marseilles, in the middle of August. Either after several weeks of abnormally hot water due to the heat wave in the Calanques, with peaks at 27 degrees.
“People came up from the water in tears”
The alert was given to the association by diving clubs in the region ten days ago. “Diving club directors called me to tell me that groups were coming up from the water in tears,” says Solène Bastard, the association’s deputy director. Supported by researchers and the Calanques National Park, the members of the association hastily organized a series of dives, to get to the bottom of it. Objective: to immerse yourself in as many places as possible in the Calanques to observe and photograph any damage, but also to collect the dead gorgonians in order to have them analyzed, after having placed them in test tubes.
And, since the first dives that occurred on Monday, the same scenes of desolation have been repeated. On this Thursday morning, the Caveman take the direction of the coral cave, a top scuba diving spot. Barely out of the water, Tristan Estaque and his colleague Justine rethread their flippers, looking for the precious gorgonian. A few minutes later, the report is final. When she resurfaces, Justine gestures overwhelmed to the other members of the crew. “Everything is necrotic or almost,” says Tristan Estaque. Out of the hundred colonies, he has maybe twenty healthy ones. This is the first time in my life that I have seen such recent necroses. »
“Sponges are starting to die”
In the cabin of the boat, Quentin Schull labels one by one the test tubes which will be sent for analysis to the laboratories of the University of Aix-Marseille and the Oceanographic Institute of Monaco. “Usually, we don’t do this on the boat but on land in the laboratory, explains the researcher in ecophysiology at Ifremer-Marbec. But there, the phenomenon was so fast that we are in constant flux. And what we see is that everything is dying. Usually, at the end of the summer, we have 10 to 15% mortality of the gorgonians. Here, we reach 90%. It is the carnage. »
A mortality that could lead to others, when we know that gorgonians constitute a natural habitat for many species. “The gorgonians have turned white, and all the fish that sheltered here are no longer there, regrets Tristan Estaque. Sponges are starting to die. Molluscs too. We only found the shells. And it’s all over. “At the next storm, the current will carry away the coral skeletons. And scientists estimate that it will take half a century for the gorgonians to return as they were in that corner of the Mediterranean.