Listen to part of a lecture from a biology class.

So we've been talking about how the world's oceans are getting warmer, and one consequence of these rising water temperatures involves coral reefs. These underwater reefs can die when the water gets too warm, and because the coral reefs are made up of millions of tiny organisms and provide habitats for all sorts of plants and animals. They're an essential part of the ocean ecosystem. So scientists are very interested in protecting coral reefs, and are coming up with some innovative strategies to do this. One strategy that's already been tested is to actually reduce the water temperature around ocean reefs in order to prevent further damage to them, and scientists have developed some creative ways to do that, including blocking some of the sunlight that comes down through the water and further warms the reef. For example, scientists have experimented with using large shade cloths, pieces of cloth that can be placed right on the water's surface, directly over the coral reefs, and create shade for the reefs below and then beyond just preventing further damage. Scientists are also considering using technology that would allow them to repair some of the already damaged areas of reefs. By doing this, repairing some areas of a reef, they may be able to stop the entire reef from dying off. For example, scientists are experimenting with using tiny underwater robots that can go underwater where human divers can't reach, and these robots would hopefully be able to add healthy corals to the damaged areas, healthy corals that could help that part of The Reef recover and thrive again.