JAKARTA, Aug. 20 (UPI) — A dramatic rise in the surface temperature of Indonesian waters has devastated local coral populations, research shows.

Marine biologists with the Wildlife Conservation Society, in an initial survey of the waters in May, found that more than 60 percent of the coral had “bleached,” which occurs when algae living within coral tissues are expelled.

By August, surveys by researchers from Australia’s James Cook University and Indonesia’s Syiah Kuala University showed 80 percent of those bleached corals had since died.

“It’s a disappointing development, particularly in light of the fact that these same corals proved resilient to other disruptions to this ecosystem, including the Indian Ocean Tsunami of 2004,” said Stuart Campbell, marine program director for the Wildlife Conservation Society of Indonesia.

Sea surface temperatures in the Andaman Sea — an area that includes the coasts of Myanmar, Thailand, the Andaman and Nicobar Islands, and north western Indonesia — have been on the rise.

According to the National Oceanic and Atmospheric Administration’s Coral Hotspots Web site, air temperatures in the region peaked at 93 degrees Fahrenheit in late May, representing a 7 degree rise over long-term averages for the area.

The coral bleaching is caused by a combination of warmer water and greater exposure to sunlight that is unfiltered by clouds or wind.

The August findings represent “a tragedy not only for some of the world’s most biodiverse coral reefs, but also for people in the region, many of whom are extremely impoverished and depend on these reefs for their food and livelihoods,” Caleb McClennen, marine program director for the society, said in a statement.

“It is another unfortunate reminder that international efforts to curb the causes and effects of climate change must be made if these sensitive ecosystems and the vulnerable human communities around the world that depend on them are to adapt and endure,” he said.

Clive Wilkinson, a coordinator at the Global Coral Reef Monitoring Network in Australia, told the Voice of America the bleaching appears to be spreading to Vietnam and Southeast Asia. He warned that it could reach Taiwan and southern Japan very soon.

“We’re sadly quite convinced that this is a climate change event,” Wilkinson said. “What’s happened is that there is far more energy in the atmosphere and in the oceans at the moment because of global warming.”

While coral reefs account for just 1 percent of the world’s ocean surface, they provide a home for 25 percent of all sea life.

Coral reefs are a sight to behold. Great coral reefs in the world, such as the Great Barrier Reef in Australia, Belize Barrier Reef in Mexico, Red Sea Coral Reef in the Middle East and the Tubbataha Reef in the Philippines are testaments to the magnificence of natural underwater treasures.

However, coral reefs are also among the most susceptible to environmental destruction. One challenge for the existence of coral reefs is coral reef bleaching.

Coral bleaching is the whitening or fading of coral colors due to the expulsion of the zooxantheallae, a type of a unicellular algae, from the coral system. The zooxantheallae gives the coral reefs its sparkling, gorgeous colors. The loss of zooxantheallae is a sign that the coral reef is undergoing stress, thus a coral reef bleaching occurs. The bleaching signals that environmental imbalance is going on underwater, and the loss of color is the coral reef’s response to these stressors, or imbalance.

Coral reef bleaching is a result of both pathogenic and anthropogenic (human-induced) factors. Pathogenic infection is caused by the bacteria Vibrio Shiloi which is triggered by a marked increase in temperature. Mostly in the summertime, the bacteria unleash heat-sensitive toxins that attack the zooxanthellae in coral reefs.

Human activities contribute to coral reef bleaching. The two major culprits are global warming that induces high sea surface temperature and the increase in solar irradiance that penetrates bodies of water, producing photosynthetical radiation and ultra-violet (UV) light. The thinning of the Earth’s ozone layer and activities like cutting down of trees and destruction of naturally occurring shades enable too much sunlight to penetrate the depths of oceans and seas. Other causes include too much acidity in the ocean, overfishing that destroys marine food cycle and changes in the salinity of seas and oceans, among others.