This story was originally published by the Guardian and is reproduced here as part of the Climate Desk collaboration. A huge coral reef has been discovered off the coast of Tahiti in the Pacific Ocean’s “twilight zone,” offering hope that more pristine ecosystems are waiting to be discovered at unexplored depths. Stretching along the ocean floor for nearly two miles, the reef, covered in rose-shaped corals, is one of the largest such discoveries at depths of more than 30 meters, where sunlight levels are much lower. Scientists for the Unesco-led mission in French Polynesia said the reef, discovered in November, did not appear to have suffered bleaching events that had damaged neighboring reefs in shallower waters in 2019.