Extreme Heat Puts Coral Reefs at Risk, Forecasts Say
This year’s extreme heat is putting the world’s coral reefs under such severe  stress that scientists fear widespread die-offs, endangering not only the  richest ecosystems in the ocean but also fisheries that feed millions of people.From Thailand to Texas, corals are reacting to the heat stress by bleaching,  or shedding their color and going into survival mode. Many have already died,  and more are expected to do so in coming months. Computer forecasts of water  temperature suggest that corals in the Caribbean may undergo drastic bleaching  in the next few weeks.  What is unfolding this year is only the second known global bleaching of  coral reefs. Scientists are holding out hope that this year will not be as bad,  over all, as 1998, the hottest year in the historical record, when an estimated  16 percent of the world’s shallow-water reefs died. But in some places,  including Thailand, the situation is looking worse than in 1998. Sigue en: http://www.nytimes.com/2010/09/21/science/earth/21coral.html?_r=1&hp