Off the coast of Corsica, strange rings dot the seabed. How did they come about? The documentary " Cap Corse: the mystery of the rings ", directed by Yann Rineau, tells the story of a multi-disciplinary scientific investigation and an extraordinary underwater expedition, led by diver and naturalist Laurent Ballesta in collaboration with scientists including Prof. Edouard Bard, holder of the Chair in Climate and Ocean Evolution at the Collège de France, and his team, who took part in this adventure in their CEREGE laboratory and in the field or underwater in a submarine off Cape Corsica.
It's a curious phenomenon observed in 2011 on a sonar screen during an oceanographic campaign in the Cape Corse and Agriate Marine Park. Twenty kilometers off the coast of Corsica, on a vast plain of sand at a depth of over 100 meters, 1,417 regular circular shapes can be seen over an area of almost 15 km². Almost perfect rings, 20 metres in diameter, seemingly drawn on the seabed. These unusual geometric patterns aroused the curiosity of the scientific community.
After long preparation, a large-scale expedition is about to unravel their secret. The expedition is led by Laurent Ballesta, diver, photographer, naturalist and specialist in extreme diving, who is surrounded by a multi-disciplinary team of researchers, including Edouard Bard and his colleagues at CEREGE, who are responsible for numerous scientific protocols.
For the dives, the expedition mobilized observation submarines and a pressurized bathyal station, enabling divers to explore the deep without time limits, while living confined for twenty days in a cabin measuring just a few square meters. This feat was made possible thanks to the logistical support of the French Navy, which provided a military vessel to ensure their safety.
This documentary film retraces three years of a scientific investigation full of twists and turns which, after the first scouting dives revealing a surprising underwater landscape, led to a series of major discoveries, pleasant surprises and disappointments. Unexpectedly, these strange rings tell us about the Earth's last ice age. From analysis to hypothesis, investigations gradually uncover the mystery of the origin of these strange rings and their unique ecosystem, reminding us of the extent of our ignorance of the sea closest to us, the Mediterranean.
The film "Cap Corse: le mystère des anneaux", directed by Yann Rineau, will be broadcast on the ARTE channel on Saturday May 3 at 8:55pm, and will be available on arte.tv from April 26, 2025 to August 2, 2027. A film written byYann Rineau, Laurent Ballesta and Aurine Crémieu - Coproduced by ARTE France, Les Gens Bien Productions, Andromède Océanologie.
