New findings suggest that out-of-sight deep reefs are unique habitats in need of protection. A team of highly trained scientific divers—led by researchers from the California Academy of Sciences—explored Pacific and western Atlantic reefs to test a widely held hypothesis that climate-stressed life from shallow reefs can take refuge at mesophotic depths (100—500 feet beneath the ocean’s surface). The results are clear: deep and shallow reefs are actually different systems with their own species, and deep reefs are just as threatened by climate impacts, storms, and pollution as their shallow counterparts. Their work, published today in Science, represents a major shift in thinking for scientists, conservation managers, and members of the public hoping to give coral reefs a fighting chance.