Our coral reefs in hot water due to El Nino

PETALING JAYA: Malaysia is facing the largest loss of its coral reef population in history with the waters around the country getting warmer from next month.

Universiti Malaya coral reef ecologist Affendi Yang Amri said climate change coupled with a strong El Nino could threaten up to 90% of the country’s coral reefs.

Affendi said that sea temperatures could rise 2°C above the threshold of the corals, stressing them.

“Usually if waters are at or above 31.5°C for two weeks, they will start to bleach,” said Affendi.

He said the rise in temperature causes the breakdown of the symbiosis between the corals and their zooxanthellae (symbiotic algae).

It is the zooxanthellae which gives the corals their colour and is also the corals’ main provider of food.

Affendi added that bleaching occurs when the corals expulse the zooxanthellae, leaving the animal tissue exposed and making its white skeleton visible.

“Corals get 90% of their food from the algae. So when the algae is expulsed, the corals begin to starve,” he said.

He said that when bleached and the water temperature does not drop to 30°C or lower for another three weeks, the corals will start to die.

“The year 2010 saw the last big El Nino and many corals in Malaysia bleached and about 30% died, but we are afraid this year could be more severe.

“The warm temperature could remain for many months.

“It may be even worse than the biggest El Nino ever recorded in 1998 where 80% of the reefs in Maldives died.”

According to Reef Check Malaysia, 40% of the reefs in peninsular Malaysia died in 1998.

Affendi is now hoping that it won’t be as bad, and that at most, only 30% of the reefs would die. But the worst case scenario could see 90% of the reefs destroyed.

He said very little can be done at the moment to reduce the global stress on corals by El Nino and climate change, but steps can be taken to minimise local stress to give the corals a better chance of survival.

Local stresses include water pollution, plastic trash, coastal developments, sedimentation, sewage water, long fishing nets, fish bombing, physical contact from snorkelers and divers and etc.

“Zones with diverse and rare corals need to be prioritised as you want to minimise human contact in those areas,” said Affendi.

“Those who take tourists diving or snorkelling must also remind them not to touch or kick the corals.

“When you know that warmer waters are about to hit, there should be no boats passing through those areas, no divers and snorkelers for a few weeks until the warm period passes.”

But Affendi stressed that everything cannot be closed as that would jeopardise the livelihood of people like fishermen.

He also added that island resorts needed to step up on their sewage treatment systems as these were poor or non-existent and most of the sewage ended up in the ocean, damaging the corals.