On 3 April, the amphitheatre of the Cosquer Museum in Marseilles hosted the premiere of the documentary film "Cape Corsica: the mystery of the ringsdirected by Yann Rineau and co-produced by ARTE, about an expedition led by Laurent Ballesta. The evening brought together a large audience for introductory lectures, a preview screening and a final debate with the film's researchers and protagonists, including several members of CEREGE.
📅 TV broadcast: Saturday 3 May at 8.55pm on ARTE
A multidisciplinary and immersive scientific investigation
Off the coast of Cape Corsica, at a depth of more than 100 metres, a fascinating discovery has intrigued the scientific community for more than ten years: 1,417 mysterious, almost perfectly circular rings, each measuring around 20 metres in diameter, line the seabed over an area of almost 15 km². Their origin is an enigma.
It was in 2011, during an oceanographic campaign in the Cap Corse and Agriate Marine Park, that these unusual geometric shapes were detected for the first time on sonar images. To unravel this mystery, a large-scale expedition has been set up, led by Laurent Ballesta, diver, photographer, naturalist and specialist in extreme diving. With the support of the French Navy, Andromède-Océanologie and a team of scientists, including several from CEREGE, the expedition is mobilising unprecedented technological resources, including remotely piloted and manned submarines and a pressurised bathyal station for deep and technical dives.
For several weeks, four divers lived confined to a module measuring just a few square metres, enabling them to explore the deep sea without time limits. In the field, CEREGE scientists played an active role in the development and deployment of numerous geochemical, sedimentological and palaeoclimatological protocols, both on land and at sea.
The investigations reveal an exceptional ecosystem, home to an unsuspected biodiversity, with species never before observed in this context. Through diving and analysis, the researchers are shedding light on the influence of the last ice age on the formation of these rings and on the current dynamics of the Mediterranean seabed.
The film recounts three years of intense research, punctuated by discoveries, hypotheses, disappointments and surprises. Laurent Ballesta's spectacular underwater images plunge viewers into a fascinating world, revealing the mysterious beauty of these rings and the life they harbour.
Extracts from the ARTE film "Cap Corse, le mystère des anneaux" An expedition by Laurent Ballesta, directed by Yann Rineau
To find out more about the subject, you can watch the lecture given by Édouard Bard on 30 April as part of the Mercredis d'Endoume programme, available at IMBE WebTV. He discusses "The last deglaciation and its implications for the study of the Cosquer cave and the coralligenous rings of Cap Corse".