Since 2017, the Under the Pole team has been sailing the seas, between the Arctic and the Pacific. The current mission, DeepHope, aims, since July 2018, to collect mesophotic coral between 30 and 150 meters deep, in hopes of restoring surface corals. In April, they set a record by collecting a sample at 172 meters deep in the Gambier archipelago in French Polynesia. In early April, in the Gambier archipelago in French Polynesia, Ghislain Bardout, co-founder of the Under The Poleexpeditions, along with two divers from his team, set a record: they collected a mesophotic coral at 172 meters deep, a specimen of Leptoseris hawaiiensis. » I have been waiting for such discoveries for 40 years « , says Michel Pichon, researcher for the Criobe. Scientists had indeed noticed that corals were migrating to the seabed. This finding thus reassures researchers about the idea that corals have adapted to drastic living conditions and have found refuge at the bottom of the oceans to develop there. According to Laeticia Hédouin, CNRS research officer at the Insular Research Center and Environmental Observatory, » the collection of this mesophotic coral raises new intriguing questions about their ability to survive in these hostile environments. »
It is now known that corals near the surface are endangered and » the chances of survival for the reefs are very low against the unprecedented changes the planet is undergoing » explains Laetitia Hédouin. However, thanks to this study, hope is permitted, the researchers discovered that » more than 60% of surface coral species are capable of colonizing the depths. […] They now represent a true hope for restoring reefs through the provision of larvae that can recolonize the surface. « , assures Laetitia Hédouin. The divers of Under The Pole have the mission to collect samples of these deep corals to allow researchers to study them. Their goal is to » test the hypotheses concerning the capacity of mesophotic coral environments to serve as a refuge and their role in the reseeding of degraded reefs « , specifies Michel Pichon.
The result of collaboration between scientists and diversThe alliance of the Under The Pole team and the scientists of Criobe gave birth to the project DeepHope. Indeed, scientific diving is generally limited to 30 meters deep, due to strict legal frameworks and a lack of skills. This restricts research to surface waters and prevents numerous discoveries. For Michel Pichon, » this collaboration between scientists and highly specialized divers is a revolution for underwater research, and technical diving using rebreathers is undoubtedly the technique of choice for this type of study. » These rebreather immersions have enabled the efficient collection of 4,000 samples within a year.
The program DeepHope will conclude in June. The results of the expedition will be presented at the International Coral Reef Symposium in 2020, in Bremen, Germany. But the adventure does not stop there, the team begins a new mission in Moorea, in August 2019. » We will take on a new challenge, that of saturation diving « , affirms Ghislain Bardout. As part of this new study, the Under The Pole III team has designed an underwater habitat called « the capsule » allowing divers to spend several days underwater. Although they continue their immersions in the mesophotic environment in parallel, their main research will take place in this capsule—situated between 12 and 20 meters deep—to study a key moment in coral life: its sexual reproduction.
Cover photo © Franck Gazzola / Under The Pole / Zeppelin Network
Julien Barletta