Singapore ready to deal with threat to corals

Audrey Tan, Straits Times AsiaOne 4 Mar 15;

Safeguards targeting rarer coral species to be put in place if seas become too warm: NParks

Even though Singapore has lost over 60 per cent of its coral reefs through extensive land reclamation, its waters are still home to about a third of the world's hard coral species. But they could still be under threat - this time from warming seas as a result of climate change.

The National Parks Board (NParks) is ready to jump into action if sea surface temperatures creep up to a point that Singapore's corals are in danger of bleaching.

A coral safeguard programme targeting rarer coral species will be implemented, said Dr Karenne Tun, deputy director of the coastal and marine division at NParks' National Biodiversity Centre.

"We will collect fragments of these species from as many colonies as we can find, and grow them out in various reef areas as well as in aquaria, to ensure that we are able to maintain the population," she told The Straits Times. "We will also out-plant them back on the reefs after the bleaching event passes."

Meanwhile, NParks has initiated monitoring schemes to better understand how elevated sea surface temperatures may influence the photosynthetic responses of corals.

Coral reefs cover just 284,000 sq km of the ocean floor - about 0.1 per cent of the total ocean area - but they support a surprising amount of biodiversity. Around the world, these underwater palaces support about 30 per cent of all described marine species.

In Singapore waters, there are more than 250 species of hard corals. The total reef area here is an estimated 13.25 sq km.

But even as a global climate pact was forged in Paris last December, coral reefs worldwide are reeling from the impact of climate change.

Marine scientists say coral reefs are one of the habitats most under threat, due to the dual effects of ocean warming and ocean acidification. "Ocean warming is a direct impact of climate change that increases temperature stress on corals," said Dr Intan Suci Nurhati, a coral researcher from Singapore-MIT Alliance for Research and Technology.

When carbon dioxide dissolves in the ocean, carbonic acid is formed. The increasing acidity will lead to higher rates of erosion of the physical structure of reefs, said Assistant Professor Huang Danwei, a marine biologist from the National University of Singapore's (NUS) department of biological sciences. Current and projected rates of global warming mean many stony corals will expel the symbiotic microalgae living within them and nourishing them, Prof Huang added. But expelling the algae causes coral bleaching.

In October last year, science journal Nature reported widespread coral bleaching. This caused the United States National Oceanic and Atmospheric Administration to officially declare a global bleaching event on Oct 8, the third in recorded history, after 1998 and 2010.

These were El Nino years, referring to the phenomenon linked to prolonged warmer weather that is expected to continue this year as well, with scientists warning of bleaching events. In 1998, about 25 per cent of corals here died, while 5 per cent of them did so in 2010.

Prof Huang, who runs the Reef Ecology Lab at NUS, said coral reefs can protect shorelines and support recreation and tourism.

"The dive trail at the Sisters' Islands Marine Park attests to that. We have many more coral reefs that have the potential to become world-class dive sites, right in our backyard."

Viruses 'may be keeping coral reefs healthy'
Straits Times 4 Mar 16;

Coral reefs are one of the most vibrant and colourful habitats of the ocean, but the key to their health could lie in organisms not visible to the naked eye.

Microbial communities comprising viruses and bacteria could be the unlikely drivers of coral reef health, according to research by a marine biologist from Nanyang Technological University .

During a study of a pristine ring of coral in the Chagos Archipelago in the Indian Ocean, Associate Professor Federico Lauro found that the water within the coral ring contained more of a type of virus than the surrounding water, despite constant water exchange.

The Italian's research has indicated that it could be these viruses that are helping the coral reefs there to thrive.

Known as bacteriophages, the viruses can infect and break down a type of cyanobacteria - organisms that make their own food through photosynthesis - called Synechococcus. The destruction of Synechococcus releases nutrients such as nitrogen- and phosphorous-based compounds, which nourish the corals.

"Not all viruses are bad. Some of them are good and, in this case, they could play a role in cycling nutrients," said Prof Lauro.

"In a healthy human, there is a balance of the different types of microbes in the body, and it is the same for coral reefs."

The Chagos Archipelago is uninhabited except for military personnel, and is part of a marine protected area established by Britain. The water there is clean, and the coral reefs in the area are considered among the healthiest in the world.

Prof Lauro's research has wider implications for coral reef conservation, as scientists can now look beyond physical factors, such as sedimentation, to determine why reefs are dying and how to restore them.

"There is a clear indication that the viruses have an effect on the Chagos coral atoll, and it is interesting to study how biological factors are affecting other reefs," he said .

The research was conducted aboard his own recreational sailing boat, the 18.5m Indigo V. "This shows that you don't need a large oceanographic vessel to do good science, and a lot more ocean samples can be collected by recreational boat owners who are sailing the world in their own time," he said.

His study cost $70,000, a fraction of what a similar study on board a large oceanographic vessel with high-tech scientific devices could cost. For his work, he clinched the prestigious Lowell Thomas Award for Innovation in Conservation last November.

This is an international award which last year was given to explorers who exhibit excellence and innovation in conservation, with emphasis on emerging techniques and technologies. Past winners include Sir David Attenborough, the golden voice of nature documentaries, and Edwin "Buzz" Aldrin, one of the first men to walk on the moon.

On his win, Prof Lauro said: "It was surprising, considering that the past winners like Sir David Attenborough are so good, but I hope that the win will help us get funding for the Indigo project, for more exciting science."

He is due to set off on another research trip to the Indian Ocean on board Indigo V later this month.

Assistant Professor Huang Danwei of the National University of Singapore's Department of Biological Sciences said: "The methods established (by Prof Lauro) also pave the way for a convenient approach for even non-scientists to contribute to the monitoring of various marine environments, including coral reefs, which have distinct microbial signatures."

Audrey Tan

Polluted waters: Corals fight back
Coral reefs are the world's underwater gardens and guardians of life. But, as oceans warm and become more acidic due to climate change, these important habitats are at risk. The good news is that nature is resilient. New scientific research has uncovered more information about coral reefs, which could help in their conservation. The Straits Times takes a look at the links between climate change and coral reefs.
Audrey Tan Straits Times 4 Mar 16;

Murky waters full of sediment may make it difficult for scuba divers to explore under water, but they have a far more ominous impact on marine life.

Corals, in particular, are exceptionally vulnerable. As well as grappling with the effects of climate change, sedimentation caused by land reclamation or pollution is also posing a challenge.

Sunlight does not penetrate sedimented waters as well as in clear waters. This affects the photosynthetic ability of the microalgae living in the coral to produce food, which nourishes the host.

High levels of sediment in the water can also physically smother corals and affect their reproduction.

Unlike broadcast-spawning coral species, which release male and female sex cells in a spectacular fashion, colouring the waters a milky white, brooding coral species establish new colonies in a less extravagant way.

The fertilised egg, or larva, is released into the water column and carried to another part of the ocean, where it starts developing new colonies. But sediment collecting in coral crevices could prevent the larva from being dislodged or hinder its development.

Nature, however, is resilient.

Scientists from the National University of Singapore's Tropical Marine Science Institute (TMSI) have discovered an encouraging adaptation in the native blue coral Heliopora coerulea that seems to help it thrive in sedimented waters.

During brooding, the female Heliopora coerulea holds a fertilised egg using feathery tentacles. The inflated tentacles help to elevate the larvae above the sediment layer that has accumulated on the colonies.

"The inflated polyps protrude from accumulated sediment in the colony crevices, thus raising the brooded larvae above the layers," said Dr Toh Tai Chong, 31, a research fellow at TMSI who led the project.

The discovery was recently published in science journal Marine And Freshwater Behavior And Physiology.

Dr Toh and Mr Lionel Ng, a research assistant at TMSI, were conducting coral reef surveys at the offshore islands south of Singapore in April 2014 as part of a study to assess the effectiveness of reef rehabilitation efforts here when they noticed a patch of white while swimming over some Heliopora coerulea corals.

"It looked like a dense white mat was laid over the corals," said Mr Ng, 32.

The researchers believe their findings could help with the conservation of Heliopora coerulea, which is listed by the International Union for Conservation of Nature as being vulnerable to extinction.

"We have a lot more broadcast spawners than brooders, and little is known about the reproductive biology of Heliopora coerulea," said Dr Toh.

The United States National Oceanic and Atmospheric Administration estimates that while three-quarters of stony corals are broadcast spawners, the remaining quarter of coral species are brooders.

"Since the Heliopora coerulea broods only once a year around April, this discovery enhances our existing knowledge on the biology of reef organisms, which could help us better manage the areas they are found in to reduce disturbance and further sedimentation during the reproductive season," said Mr Ng.

Dr Toh also pointed out that since sedimentation affects all types of coral, further research could look into the different adaptation strategies to improve our understanding of how Singapore's reefs remain resilient.

This also facilitates the conservation of more vulnerable species through measures such as artificial propagation to reduce the risks of local extinction.

Dr Karenne Tun, deputy director of the coastal and marine division at the National Parks Board's (NParks) National Biodiversity Centre, said coral reefs will ensure the availability of marine-based resources, such as food and breeding spaces, and continue to support the ecosystem's resilience to a changing climate.

"NParks continually works with various coral reef researchers (here) to increase our knowledge of Singapore's coral reefs and develop better management strategies of coral reefs through our targeted conservation programmes, such as the setting up of the coral nursery and the initiation of a coral bleaching monitoring programme."

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