Summer Bay House Reef at Lang Tengah Island, Terengganu. Credit: K.L. Chew.

Building Arks for Corals

Scientists scramble as rising sea temperatures are expected to decimate coral reefs.  A story in the Asia’s Water Crisis project.

CORAL REEF ecologist Affendi Yang Amri had hated the idea of coral restoration for most of his 27-year career.

Wary that opportunists would ramp up destructive coastal works if corals could be “restored” elsewhere later, he preferred protecting existing corals rather than fixing damaged ones.

But in 2018, scientists on the Intergovernmental Panel on Climate Change (IPCC) warned of an imminent coral collapse worldwide. 

(Summer Bay House Reef at Lang Tengah Island, Terengganu. | Photo: KL Chew)

They projected that up to 90% of tropical coral reefs will die if average global temperatures rise by 1.5 degrees Celsius. Unless nations meet their pledges to cut carbon emissions, mass coral death will happen by 2030. That is eight years away.

Immediate solution needed

Shocked by the spectre of hollow coral shells and deserted reefs, Affendi dived into something he once vowed never to touch. 

“I had to change my mind. I had to realise that now, coral restoration or coral rehabilitation was one of the only ways that we can save our coral reefs. 

“Because if we don’t buck up and find out the best way, what chance do our reefs have?” he tells Macaranga.

Today, his team at Universiti Malaya is running experiments to develop evidence-based best practices for coral rehabilitation programmes.

Affendi Yang Amri at one of the Universiti Malaya laboratories he and his team work from. (Annabelle Lee)
Affendi Yang Amri at one of the Universiti Malaya laboratories he and his team work from. (Annabelle Lee)
The critical Coral Triangle

A remarkably rich diversity of corals line the coasts of Malaysia. At least 584 species of hard corals live there, compared to the 410 species in Australia’s Great Barrier Reef, which is 100 times larger in area.

Ninety percent of Malaysia’s coral species can be found off the northern and eastern coasts of Sabah. This stretch is part of the Coral Triangle an area that harbours the highest marine biodiversity in the world. 

Like rainforests on land, coral reefs shelter and feed a vast variety of animals, from shrimps to fishes to turtles. Some 826 species of reef fish have been recorded in Malaysia’s reefs alone, according to global database FishBase

A healthy coral reef further benefits tourism and fisheries, especially for local coastal communities who tend to depend on it for their livelihoods. 

For example, a UN Environment Programme study estimated that the economic returns of the entire Coral Triangle to be US$14.5 billion in 2017, mostly from tourism and commercial fisheries.

In contrast, by 2030, a degraded Coral Triangle would lose $6.5 billion in returns compared to a healthy one.

A map showing the Coral Triangle and the Coral Triangle Initiative.
Source: United Nations Environment Program. Credit: (Macaranga) Annabelle Lee; (CommonWealth Magazine) Dennis Tseng, Steven Yeo, Sy Huang

But coral reefs and all the lives and livelihoods that depend on them are severely threatened by climate change, particularly ocean warming.

As industries and societies emit more greenhouse gases like carbon dioxide, these gases trap more of the sun’s heat in the atmosphere, explains Universiti Malaysia Terengganu oceanographer Mohd Fadzil Akhir. 

A good portion of this extra heat is absorbed by the oceans. Over time, the oceans warm up.

Partner lost in hot water

This is disastrous for corals which are incredibly sensitive to temperature changes. A mere rise of 1 2 ℃ in their vicinity can cause corals to bleach, starve, and die.

As Universiti Malaysia Terengganu coral ecologist James Tan Chun Hong explains, corals get many of their nutrients and all their vibrant colours from the algae that live inside their surface tissues. Most of the time, the algae and corals protect and feed each other.

But when the water warms up, corals expel their algae. One widely accepted – though inconclusive – explanation is that the heat pushes algae into releasing a barrage of harmful side-products.

To save themselves, the corals cast out their partners, turning white as a result – thus the term ‘coral bleaching’. Prolonged bleaching would starve and kill the corals.

Coral bleaching is caused by warmer seas that trigger the corals to expel their symbiotic algae.
Credit: (Macaranga) Annabelle Lee; (CommonWealth Magazine) Dennis Tseng, Tse Wei Chen, Sy Huang
Coral bleaching is caused by warmer seas that trigger the corals to expel their symbiotic algae.
Credit: (Macaranga) Annabelle Lee; (CommonWealth Magazine) Dennis Tseng, Tse Wei Chen, Sy Huang

Multiple rounds of bleaching have hit Malaysia’s coral reefs, according to the Global Coral Reef Monitoring Network. There was mass bleaching in tandem with the rest of the world in 1998, 2010 and 2016  and localised events for most years between 2012 and 2020.

More bleaching expected

While corals can bounce back from bleaching, scientists like Tan and Affendi worry that global warming will overwhelm this resilience with more often bouts of bleaching, giving reefs less time to recuperate between each episode. 

Already, a pattern of more frequent bleaching is emerging in Malaysia.

Malaysia recorded mass coral bleaching in 1998, and then seven more mass and local bleaching since 2010.
Credit: (Macaranga) Annabelle Lee; (CommonWealth Magazine) Dennis Tseng, Steven Yeo, Sy Huang

In a worst-case scenario of global warming, Affendi projects that Malaysia could lose “80 to 90 percent” of its corals by 2050 if nothing is done. Along with scientists Fadzil and Tan, he warns that climate change is the biggest threat to coral reefs. 

However, the government’s Marine Park and Marine Resources Management Division argues otherwise.

Speaking from her ground experience working at different marine protected areas across the country, division officer Izarenah Md Repin thinks that corals are more affected by local impacts than climate change.

Address local pressures first

For one, she says she has not noticed any drastic rise in sea temperature.

“Perhaps if you ask a researcher, they will say climate change is the major issue but as a manager who faces corals every day, I feel that climate change is still manageable. 

“It is the local threats like untreated sewage that we really need to address,” she says.

Izarenah notes that corals often fail to recover when damaged by chemical pollution or physical breakage. However, corals have shown resilience to bleaching events.

Citing data from Reef Check Malaysia, which conducts annual reef monitoring programmes, she says mass bleaching in 2010 had cut Malaysia’s average live coral cover from almost 50% in 2009 to 42.6% in 2011.

After her division intervened by imposing island closures, average live coral cover recovered to 46.7% in 2013.

Don’t underestimate climate change

Affendi agrees with the need to remove local threats to corals, as that would improve their survival in a warming sea.

However, he calls for more drastic action – such as a government policy that mandates all marine-related industries to work together to mitigate the impacts of climate change. 

Still, to Affendi, Izarenah’s argument shows that scientists need to work harder to communicate the IPCC report and convince those in governments about the imminent threats from climate change.

Bleached Bleached Porites (white stony corals on the right) at Rawa Island, Johor. (KL Chew)Porites (white stony corals on the right) at Rawa Island, Johor. (K.L. Chew)
Bleached Porites (white stony corals on the right) at Rawa Island, Johor. (KL Chew)

Building coral arks  

Coral rehabilitation programmes – usually where corals are planted and grown in designated nurseries – have spawned across Malaysia in recent years. Numerous dive centres and resorts do it as part of their corporate social responsibility efforts. 

However, programmes are rarely run by scientists and rehabilitation techniques are not regulated. Efforts are often small-scale, short-term and loosely monitored. 

There is also no formal requirement for results to be reported.

How to best grow corals

Notable science-driven coral rehabilitation initiatives are currently underway in the Great Barrier Reef in Australia, Florida, USA and Palau, and Affendi is working to bring that level of scientific rigour to programmes in Malaysia.  

Since 2019, he and his team of scientists have been working on Project PULIH (Protecting Underwater Life through Integrated reHabilitation). ‘Pulih’ is also the Malay word for ‘healing’.

They are running experiments to determine which corals and of what ages are most suited for replanting, and how other creatures like sea urchins can spur coral growth. 

They are also testing various setups for best results. One study examines if floating “coral tree” nurseries could outperform the conventional nurseries that lie on the sea bed.

Another compares how corals respond to warmer water when shielded from the sun with black anti-ultraviolet ray net, the same typically used in gardens. Early findings suggest that shielding corals can reduce bleaching.

A scientific way for all

The project’s end goal is to develop a set of data-driven best practices for coral rehabilitation and to convince programmes across the country to implement them for more consistent results.

As tropical nations struggle to respond to the almost apocalyptic threat posed by warming seas, Affendi has a last-ditch proposal to face the impending coral reef collapse. 

Every island in the country ought to have an “ark” to preserve Malaysia’s diverse coral species.

“If we can perfect coral rehabilitation and coral nurseries, in the end, this could be our arks.”

[Edited by YH Law]

This story is part of Asia’s Water Crisis, a collaborative project of five media organisations, including Macaranga, and led by CommonWealth Magazine in Taiwan. The project examines how people are responding to water and climate crisis across the continent.

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