Novel temporal approaches for the study of cold-water coral reefsUnderexplored Reefs

Marin Marcillat¹, Julie Tourolle¹, Lénaick Menot¹

¹UMR BEEP, Ifremer, France

Similar to their tropical analogues, cold-water colonial scleractinians are autogenic engineers that create complex habitats and thus provide important support, provision and regulation services. In the Bay of Biscay, these CWC thrive in the many submarine canyons incising the continental margin. However, even in the deep sea, these ecosystems are threatened by anthropogenic activities with cumulative impacts from trawling, pollution, warming and acidification of the ocean. Thus, the good conservation status of these vulnerable species is the target of a growing number of regional and international regulations. To better understand the functioning of these ecosystems and eventually provide guidance on their preservation, long-term and high-frequency monitoring strategies need to be set up. So, in the framework of the Life Integrated Marha and ChEReef projects, several imagery approaches have been developed to understand CWC spatiotemporal dynamics and to monitor their health, behaviour and distribution. An autonomous seabed observatory has been deployed in the Lampaul submarine canyon, at 800m depth, for long-term monitoring of coral behaviour and associated fauna (four years). Multi-year multi-species 3D mapping of several study sites has also been produced in order to assess the spatiotemporal dynamics of coral distribution. The outcomes of this project should ultimately lead to better environmental management of cold-water coral reefs and raise public awareness of the need to preserve these vulnerable ecosystems.