THAILAND   –  More than 10 diving sites in Thailand’s national marine parks have closed due to widespread coral bleaching, amid the country’s continued efforts to seal off its famous tourist attractions to protect the environment.

At its worst in over six years, coral bleach has spread widely between 40% to 80% of the reefs along both the east coast (Gulf of Thailand) and the west coast (Andaman Sea), according to Nattapol Rattanaphan, Director of the Marine National Park Division (MNPD). Koh Ma Prao and Koh Chumpon are the worst-hit areas with up to 80% of their corals having turned white, Rattanaphan told CNN. Bleaching occurs when algae that live inside corals and give them their color are expelled either due to increased sea temperatures or extreme weather events. “Sea temperature has been unusually high, reaching 34 degrees Celsius at one point,” Rattanaphan said. “This happened around early April to early May this year and lasted for several weeks.” Coral reefs would start to bleach if water temperatures go above 30.5 degrees Celsius and continue for two to three weeks, Rattanaphan added.(CNN.COM/photo: cnn.com)…[+]