Archipelago’s Coral at Mercy of Warming Oceans, Experts Say

Jakarta Globe: Archipelago’s Coral at Mercy of Warming Oceans, Experts Say


Jakarta. Coral bleaching, which was found to have occurred at an alarming rate in waters off Aceh, is happening throughout the archipelago, an environmentalist group says.

“Almost all parts of Indonesia are seeing coral bleaching as a result of sea water movements in September 2009 that raised the temperature of the sea surface,” said Anton Wijonarno, marine program monitoring coordinator at WWF Indonesia.

“The peak was in February and March, which were also Indonesia’s hottest months.”

Bleaching refers to the whitening of coral due to heat driving out the algae living within the coral tissues.

International scientists recently declared that large swathes of coral off of Aceh had died after a surge in temperatures across the Andaman Sea from the northern tip of Sumatra to Thailand and Burma.

Experts say the bleaching phenomenon in Aceh is one of the most rapid and severe coral mortality events ever recorded.

Anton said the same problem is threatening other areas in various parts of the country, such as the Karimun Jawa islands in the Java Sea, Bali, Berau in East Kalimantan, Alor Island in East Nusa Tenggara and the Wakatobi islands in Sulawesi.

“The hardest hit [among these other areas] is Wakatobi, where around 35 percent of corals have turned white,” he said.

Suharsono, director of the center for oceanography research at the Indonesian Institute of Sciences (LIPI), said the whitening of corals did not immediately spell death.

“For some sensitive corals, especially branched ones such as pocillopora or seriatopora, they’ll die sooner if it gets too hot, but those without branches are more resistant,” he said.

Anton added two other factors that influenced the ability of bleached corals to recover. “The two options [death or recovery] depend on sea water conditions and the health of the coral reefs.”

Suharsono said the latest data indicated that only 6 percent of corals throughout the archipelago were in very excellent condition, 20 percent were categorized as excellent, 40 percent medium and 30 percent bad.

“If corals are in good shape, then they will quickly recover. But those in bad condition will mostly be knocked down.”

Andrew Baird, of James Cook University’s ARC Center of Excellence for Coral Reef Studies, previously told Reuters that reefs in Indonesia normally take five to 10 years to recover from localized bleaching.

Anton blamed climate change for the phenomenon, but the scientific community is still divided on what causes sea temperatures to rise.

Suharsono said rising water temperatures and the resulting coral bleaching was a natural phenomenon that was also seen in the 1990s.

“The worst happened in Indonesia back in 1993 when 90 percent of our corals died, and in 1998 when as much as 60 percent of the corals died.”

He added that the warming of the oceans was part of a larger natural cycle and that the solution lay in the environment itself. “Nature cannot be predicted, so if water is heated by nature then it can only be cooled down by nature,” he said.

Regardless of the cause, Anton said it was necessary for people whose livelihoods depended on healthy corals, such as fishermen and tour guides, to start adapting to the situation by finding other sources of income while waiting for the delicate underwater ecosystems to recover.

He cited traditional fishermen in East Nusa Tenggara who have been adjusting to the bleaching by taking up farming. “Bleaching adaptation [strategies] would depend on the location. We need to anticipate the time it would take for corals to recover to determine the strategy,” he said.

“If recovery will take a long time, then people would feel the impact as bleaching would affect the corals’ ability to function as a home for marine life.”

The bigger problem is what to do with corals that don’t recover. Syamsul Maarif, secretary general at the Ministry of Maritime Affairs and Fisheries, said humans could do little if the corals were already dead.

“We could try to re-plant the corals, however we have no records of how successful this will be,” Syamsul said.