THE underwater world is about to put up a spectacular display - one resembling an aquatic snowstorm of pink flurries.
Known as the mass coral spawning event, billions of eggs and sperm will be simultaneously released into the water by Singapore's coral reefs.
Coral in Singapore's reefs releasing egg-sperm bundles in the mass coral spawning event in 2010. The egg-sperm bundles will break up upon reaching the surface of the sea to allow fertilisation to occur. A similar release is expected from tomorrow to Friday. -- PHOTO: KARENNE TUN
A team of eight biologists from the National University of Singapore (NUS) and National Parks Board will be documenting the annual event here by diving into the waters at the Southern Islands below Sentosa - from tomorrow to Friday, the days when the bulk of the spawning is expected to take place.
Although mass coral spawning occurs worldwide, it is especially meaningful in the Singapore context.
Dr James Guest, a coral reef research fellow at the Nanyang Technological University, said that in addition to the high sedimentation caused by development, reefs here are greatly impacted by high seaweed growth, thought to be detrimental to coral life.
Yet, past spawning events have shown that the corals here are 'capable of replenishing themselves', he said.
Furthermore, there is another reason to keep a close watch on the corals this year: to see how the reefs have recovered from the mass coral bleaching of 2010, when unusually warm ocean temperatures ravaged reefs around the world, including those off Singapore's coast.
Ms Karenne Tun, a PhD candidate at NUS, whose research is related to coral reef management, noted that the coral spawning last year was 'rather muted'.
She is one of the eight divers who will be going underwater this week to observe the event.
Ms Tun said: 'This year will be important to see if the corals have fully recovered from the bleaching by assessing the magnitude of the spawning.'
Spawning occurs only for a few nights each year shortly after the March or April full moon, during which flurries of gametes - usually pink - slowly drift about in the dark waters.
Because the release is concentrated in a small window of two to three hours, the biologists say they must work quickly to record the timings and species of corals which are reproducing.
So far, of the 255 coral species recorded in Singapore, only 69 have been documented to release their reproductive cells this time of the year.
This is because many coral species in Singapore are rare, and some complete spawning very quickly, so 'trying to catch them in the act is very difficult', said Dr Guest.
The marine biologist, who is not taking part in this week's dive, said he will use the available data here to publish a 10-year data set on Singapore's reefs. In doing so, he hopes others will use the information to better manage Singapore's reef ecosystem.
To Dr Guest, corals found here are 'as much a part of Singapore's heritage as Bukit Timah Nature Reserve or Chinatown'.
He added: 'The fact that they are spawning shows that they are persisting, and we need to protect them.'