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Coral Buffers Itself from Ocean Acidification

The coral species Porites cylindrica has an in-built mechanism that protects it from fluctuations in ocean pH, according to research reported in Proceedings of the National Academy of Sciences.

Lead author of the study, Ms Lucy Georgiou of the ARC Centre of Excellence for Coral Reef Studies at The University of Western Australia, said that a reservoir of calcifying fluid allowed the coral to continue growing even under relatively low pH conditions found in Heron Island lagoon. “The regulatory mechanism allows the coral to grow at a relatively constant rate, suggesting it may be more resilient to the effects of ocean acidification than previously thought,” she said.

Ocean acidification is caused by rising carbon dioxide, and is one of the greatest long-term challenges facing the survival of coral reefs.

While the findings are positive, it is not yet known if the adaption is species-specific and limited to colonies where there is a high fluctuation of ocean pH levels.

“We think it is most likely only typical to coral from reefs such as Heron Island lagoon, where temperature and pH fluctuations vary greatly,” Georgiou said. “The next step in this research is to find out if Porites cylindrica colonies from more stable environments also have the ability to adapt and hold up to the threats of ocean acidification.

“We also need to explore whether rising sea temperatures impact their ability to maintain a constant internal pH level.”