In the twilight depths of the Gulf of Mexico, about as deep down as a football field is long, U.S. Navy divers carefully snip small branches of corals with gloved hands. Their voices crackle through communication systems to the ship above, distorted to high-pitched tones by the helium mixtures they breathe. “These guys, they’re tough, tough Navy dudes that are saturation experimental divers,” Chris Gardner, a U.S. government fisheries biologist on the team that oversees deepwater coral restoration in the Gulf, told Mongabay. “But the audio can be a little goofy because they’re breathing mostly helium. So, there’s definitely some Mickey Mouse effects going on.” A US Navy diver descends to the twilight zone with a diving bell, which allows divers to go deep beyond recreational diving limits. Image courtesy of NOAA/C-Innovation, LLC. The surreal scene, of highly trained Navy divers speaking in cartoon voices while performing precise underwater surgery on orange and purple coral colonies, illustrates the extraordinary measures underway to restore ecosystems damaged by the British Petroleum (BP) Deepwater Horizon spill, the worst oil spill in U.S. history. This work marks one of the world’s first attempts at deep-sea coral restoration, and the largest to date, according to the U.S. National Oceanic and Atmospheric Administration (NOAA), the agency in charge of the restoration. Ancient forests of the deep Beneath the Gulf’s wind-whipped surface, down where the sunlight dims and vanishes, live slow-growing coral communities that rival old-growth forests. These underwater ecosystems have existed for millennia, creating complex habitats…This article was originally published on Mongabay