Unusually warm ocean temperatures are generating conditions that threaten to kill coral across the Pacific, North Pacific and Western Atlantic oceans. Coral bleaching occurs when coral is stressed by variations in its environment, causing it to release algae living in its tissue. The coral then turns pale or white and becomes more susceptible to disease. In severe cases, the coral can die, permanently changing the habitat for fish and shellfish.
Ocean temperatures, light and nutrient levels can possibly cause bleaching. But NOAA says only warm temperatures can cause the widespread bleaching that scientists have been recording since last year. In 2014, Hawaii experienced widespread bleaching for the first time in virtually two decades. If it happens again this year, it would be the first time in history the Hawaiian Islands saw repeated years of bleaching.
More than one-third of the world’s coral reefs this year are at risk from some level of bleaching. Reefs around Hawaii, Haiti, the U.S. Virgin Islands and Puerto Rico are among those that stand to suffer as ocean waters warm, with as many as 95 percent of U.S. corals exposed to possible bleaching conditions by the end of this year. Entirely, scientists expect more than 4,600 square miles of reef to be killed off by bleaching in 2015. The findings have caused NOAA to declare the third global coral bleaching event ever on record — the others having occurred in 1998 and 2010.
While climate change continues to drive rising ocean temperatures, researchers said, El Niño stands to worsen the bleaching effects this year. El Niño Southern Oscillation is referred to as the cycle of warm and cold temperatures, as dignified by sea surface temperature, SST, of the tropical central and eastern Pacific Ocean. El Niño is goes together with high air pressure in the western Pacific and low air pressure in the eastern Pacific.
“The coral bleaching, brought on by climate change and coupled with events like the current El Niño, are the prime and most persistent threats to coral reefs around the world,” NOAA coral reef researcher Mark Eakin said in a statement. “What really has us concerned is this event has been going on for more than a year and our preliminary model projections indicate it’s likely to last well into 2016.”
Coral cover just one-tenth of the ocean floor, but they are home to 25 percent of known marine species. Coral reefs are a critical part of the ecosystem, and their health is vital to the ocean environment and need to be protected. Hopefully scientists can discover a way or society might have to consider polluting the earth less with CO2 from factories and auto mobile emissions contributing to global warming.