The mesophotic coral reef off the coast of the West African country of Benin was once written off as a dead reef, but the emergence of new technology has rewritten this notion. HERE'S HOW EL NIÑO AFFECTS THE FUTURE OF CORAL REEFSMesophotic coral ecosystems are found in tropical and subtropical regions at depths ranging from 100 feet to over 490 feet below the ocean surface, according to NOAA. Researchers at the Benin Fisheries and Oceanological Research Institute confirmed the sonar’s signal living in the oceans’ "twilight zone." Mesophotic coral ecosystems serve as essential fish habitats for some economically and ecologically important species, which use these areas for spawning, breeding, feeding and growth to maturity. This coral ecosystem consists of light-dependent corals and associated communities, populated by organisms such as macroalgae, sponges, fish and other species unique to mesophotic depths.