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A Coral Species from Australia That Can Survive Serious Bleaching

Paper Reviewed
Bessell-Browne, P., Stat, M., Thomson, D. and Clode, P.L. 2014. Coscinaraea marshae corals that have survived prolonged bleaching exhibit signs of increased heterotrophic feeding. Coral Reefs 33: 795-804.

In a study published in Coral Reefs, Bessell-Browne et al. (2014) report that colonies of Coscinaraea marshae corals from the high-latitude mesophotic environment of Rottnest Island, Western Australia, "survived for more than eleven months in various bleached states following a severe heating event in the austral summer of 2011," after which they describe how they studied corals that either remained unbleached, were moderately bleached, or were severely bleached, in order to better understand what mechanisms utilized by the corals led to the survival of many of them. And what did they thereby learn?

The four Australian researchers discovered that (1) "novel Symbiodinium clade associations were observed for this coral in both severely and moderately bleached colonies, with clade C and a mixed clade population detected," that (2) "in unbleached colonies, only clade B was observed," and that (3) "severely bleached colonies were utilizing heterotrophic feeding mechanisms to aid survival while bleached." Based on these findings, Bessell-Browne et al. say their results suggest that "C. marshae colonies can survive with low symbiont and chlorophyll densities, in response to prolonged thermal stress and extended bleaching."

As for the larger ramifications of their findings, Bessell-Browne et al. say they demonstrate that "high-latitude, mesophotic coral populations can possess the adaptive ability to survive extreme heating events, adding to existing knowledge which indicates that some coral species will be able to adapt to, and survive, the increasing stressors expected with future climate change."

Posted 16 December 2014