Coral reef presumed to be dead is rediscovered during big moment in West Africa

A coral reef long presumed dead has been rediscovered “teeming with life” off the coast of West Africa.Researchers used sonar and underwater drones to find the thriving ecosystem deep below the surface of the Gulf of Guinea.Surveys conducted in the 1960s, focused on identifying promising fishing areas, flagged a possible deep-water coral reef.But scientists at the time assumed it must be dead.Now, using a modern sonar survey and the Deep Sea Camera System provided by the National Geographic Exploration Technology Lab, scientists have found an apparently healthy reef.The amazing discovery was described in the journal Frontiers in Marine Science.Lead author Gérard Zinzindohoué said: “It was not an easy field campaign.”“It was a mix of long days at sea, technical problems, and a lot of uncertainty.“But then we saw structures on the sonar that looked like they could be reef signatures, which gave us hope that we were close.“Next, we surveyed the structures with an underwater drone and the Deep Sea Camera System.“That was a big moment for us, because suddenly we could actually see the seafloor.“I still remember seeing those first images.“It was a mix of excitement and disbelief, because after all this time thinking about this reef, suddenly there was something real in front of us.”The historical surveys had identified a possible reef more than 50 meters (164 feet) beneath the surface and declared that it was probably dead.Zinzindohoué and his colleagues at the Institute of Halieutic and Oceanographic Research in Cotonou, Benin, reasoned that it could have been a mesophotic coral ecosystem.He said: “A mesophotic coral ecosystem lives deeper than the usual shallow coral reefs, in zones where light is much more limited.“Unlike typical shallow reefs, it does not always form a single continuous reef structure.“Instead, it can appear as patchy or scattered coral communities spread across the seafloor.”Using the historical surveys as a guide, th...