Coral reefs are incredibly fragile. Not only are most corals brittle, but they usually need pristine, clear, warm, relatively nutrient-free waters to survive. Over the past few decades, humans have put an enormous amount of pressure on coral reef environments by altering their waters and tearing up their foundations. Through water pollution, over fishing, direct physical damage, warmer ocean waters and increased acidity of the oceans, we are in danger of rapidly sending the world’s reefs into oblivion. NASA's recent Millennium Coral Reef Mapping Project found that less than two percent of coral reefs are within areas designated to limit human activities that can harm the reefs and the sea life living in and around them.

This image, taken by the NASA/USGS Landsat-7 satellite, shows Hawaii's Pearl and Hermes Atoll, which consists of a few small, sandy islands that are contained within a lagoon and surrounded by a coral reef. The island of coral is part of the recently designated Northwestern Hawaiian Islands Marine National Monument, the largest protected marine area in the world.