By: Will Ramos
(From RedOrbit) – An international team of researchers has studied a coral population in South-East Asian waters that had survived a bleaching event. What was significant about this reef was that it had also survived another bleaching event 12 years earlier in 1998.
The researchers published their findings in the journal PLoS ONE.
The researchers analyzed three different sites effected by the 2010 bleaching event and found interesting results. It had been previously understood that fast growing coral was more likely to survive these bleachings. However, in some locations, such as Indonesia, fast growing coral (staghorn corals, for example) died off in large numbers.
When researchers studied sites at Malaysia and Singapore, however, the fast growing corals were much more colorful and healthy than their bleached and slow-growing counterparts.
Dr James Guest, a joint research fellow at the UNSW Centre for Marine Bio-innovation and the Advanced Environmental Biotechnology Centre at Singapore’s Nanyang Technological University is the lead author of the study.
Guest writes in the press release “Mass coral-bleaching events, caused by a breakdown in the relationship between the coral animals and their symbiotic algae, are strongly correlated with unusually high sea temperatures and have led to widespread reef degradation in recent decades.”
According to Guest, these recent studies have proven certain species of coral to be more susceptible to bleaching events. In previous results, the severity of the bleaching events had very different results on each species. Guest and his team have data that suggests the slower, and larger species of coral will replace the faster, smaller species in the future.
The researchers noticed a trend when studying these locations. According to their data, the thermal history of each location could play a factor in how likely a species of reef will learn to adapt to its surroundings.
“…During the 2010 event the normal hierarchy of species susceptibility was reversed in some places. Corals at our Indonesian study site in Pulau Weh, Sumatra, followed the usual pattern, with around 90% of colonies of fast-growing species dying. But the pattern was the opposite at study sites in Singapore and Malaysia, even though sea-temperature data showed that the magnitude of thermal stress was similar at all sites,” Guest said.
“When we looked at archived sea-surface temperature data and past bleaching records we found that the locations that had a reversed hierarchy of susceptibility and less severe bleaching in 2010 also bleached during 1998. In contrast, the site that had a normal bleaching hierarchy and severe bleaching did not bleach in 1998.”
Guest warns that this new data, while encouraging, does not mean that reefs are immune to the effects of global warming. As shown in the results of this study, some reefs will not be able to adapt to the changing climates as well as others. Furthermore, coral reefs continue to face other dangers, such as overfishing, diseases, and pollution.