Local scientists are using an innovative new technique to preserve coral reefs, and, in so doing, the world

Coral cultivation programme on Samae San island. (Photos by Suchana Chavanich)

Having travelled around the world, including to the Arctic and Antarctic, to observe, collect and study specimens with a mission to save the deteriorating planet from climate change, marine scientist Assoc Prof Suchana Chavanich and her team now have a new job description.

"We are now a family planner for coral reefs," said Suchana, a marine biologist from Chulalongkorn University's Department of Marine Science under the Faculty of Science. "Our job is to make sure they release eggs and sperm for reproduction. If not, we figure out what to do to help them."

Suchana and a team of marine researchers and scientists, including Assoc Prof Voranop Viyakarn, who is head of the Department of Marine Science, recently announced their scientific milestone, unveiling the world's first coral-reef breeding method that utilises the frozen sperm cells of the finger staghorn coral. A collaborative project between Chulalongkorn University's Faculty of Science, Chula Unisearch, the Plant Genetic Conservation Project under HRH Princess Maha Chakri Sirindhorn's royal initiative and the Navy's Special Naval Warfare Group, the coral reef breakthrough was announced last month at the Department of Marine Science.

Global warming and climate change are a great threat to coral-reef ecosystems. In the next 30 years, 90% of the world's coral reefs are predicted to be in a decayed condition. According to Suchana, corals are known to be particularly sensitive to environmental changes. Even a temperature increase of only 1C can lead to bleaching and mass deaths.

"It's our job to do something to rehabilitate them and to keep them alive," she added.

Under a commitment to save the reefs, the Department of Marine Science started its coral breeding project in 2001. Five years later, with support from the Plant Genetic Conservation Project under Princess Sirindhorn's royal initiative, the Navy's Special Naval Warfare Group, Akajima Marine Science Laboratory in Okinawa, Japan and Taiwan's National Museum of Marine Biology, the project successfully developed Thailand's first-ever coral-cultivation programme, whereby coral sperm and eggs are fertilised.

Planula larva -- products of the fertilisation -- are then nurtured in the department's hatcheries for one-and-a-half to two years to make sure they are strong enough to be released back into the ocean.

The hatcheries, which are located at the research facility on Chon Buri's Samae San island, are able to produce 3,000-4,000 coral reefs per year. Voranop explained that there are actually several ways in which coral reefs can be reproduced. The most commonly used technique involves the attachment of a piece of reef on an artificial structure, such as concrete slabs, to anchor the corals' polyps, so they can grow into adult coral. When the structure is dumped into the sea, free-swimming coral larva can cling to it and grow.

The department later went beyond this method by initiating the coral-cultivation programme where artificial breeding is carried out. The project focuses on 10 coral species which can be broadly categorised into three groups based on their outer appearance: cauliflower coral, finger staghorn (or table) coral and brain coral.

Scientists and researchers bring coral eggs and sperm for fertilisation at a research facility on Samae San island in Chon Buri. Suchana Chavanich

"Once a year, coral reefs have spawning time where they naturally release sperm and eggs," said Voranop. "Our scientists collect coral gametes [coral reproductive cells] for artificial fertilisation. Around 36-48 hours after the fertilisation, coral larva start to swim. They are raised until they become juvenile corals and are mature enough to survive the natural world out there."

But as the ocean is getting warmer, coral reefs are bleached. The bleached corals cannot produce enough eggs and sperm to successfully reproduce.

"Apart from coral reefs, shellfish are bleached too," said Suchana. "When they are bleached, they become sick and die. Chances of reproduction then become zero."

This is how the sperm-cell-freezing technique comes into play. The process utilises cryopreservation -- the use of very low temperatures to preserve living cells and tissue -- to keep sperm cells viable for future breeding programmes. The sperm cells, according to Suchana, are stored in a liquid nitrogen tank at the ultra-low temperature of -196C to maintain the quality of sperm for future use.

"Before coral sperm are frozen, scientists conduct a procedure called sperm pre-culture, whereby the conditions of sperm are adjusted. Then the sperm cells are dehydrated, then coated with cryoprotectant [chemicals that prevent cellular freezing damage] before being vitrificated and encapsulated," explained Suchana.

"This is a similar technique, whereby the sperm of humans, dogs and cats are frozen and preserved for future fertilisation."

So far the cryopreservation technique is being carried out with Acropora humilis or finger staghorn coral only. The breakthrough was published in Cryobiology, an international journal of low-temperature biology and medicine, late last year.

While the survival rate of natural coral breeding is only 0.01% or less, corals that are bred through cryopreservation have a survival rate of between 40 and 50% after being released into the ocean.

While the cryopreservation can also be carried out with other corals, Voranop is of the opinion that not every species needs to be frozen.

Five-year-old corals bred through artificial fertilisation were released back to the ocean after being nurtured for two years in a hatchery. Photos: Suchana Chavanich

"We now focus on species that are facing the threat of extinction," said the researcher, adding that the quality of coral sperm after being frozen could be reduced by only 10-20%.

Next, the research team will be looking at ways to freeze finger staghorn coral eggs, added Suchana, as well as other coral species that face the risk of being completely gone.

Dean of the Faculty of Science, Chulalongkorn University Prof Polkit Sangvanich considers the coral breakthrough a long-awaited gift for the marine ecosystem not just in Thailand but the world over.

"Today ecosystems, especially coral reefs, are being severely and irresponsibly exploited by humans," he said. "Our discovery adds to myriad existing coral-reef-cultivation techniques, which is a good sign. When it comes to the conservation of coral reefs, using multiple techniques renders much more positive outcomes than relying on only one single method."

Suchana hopes the latest discovery will be able to not just help shield coral reefs from extinction but also enrich the community of living organisms under the sea.

"Now our concern with regard to coral reefs' spawning time is over," concluded Suchana. "Though they won't release sperm and eggs, we have frozen sperm that can be kept for future cultivation when appropriate. As a family planner, we see this as one of the ultimate solutions to save coral reefs from further extinction."