The Beacon

Elly's Hot Topics: Coral's Breakdown

Poor coral.

With global warming-generated ocean acidification already hindering the essential production of the calcium carbonate (CaCO3) skeletons in coral species, scientists now suspect another threat to corals and reef ecosystems caused by climate change.

In a new study published in the Proceedings of the National Academy of Sciences, scientists suggest that ocean acidification may also weaken the supportive cement-like framework of reef structures, making them more susceptible to erosion or destruction from strong waves and storms.

CaCO3 is fundamental in the cementation of reefs, which allows corals to adhere to one another and also fills in the empty gaps between corals. Unfortunately, with increasing oceanic uptake of CO2, carbonate ions are less available for the production of CaCO3. Researchers compared reef ecosystems around the globe in locations with naturally elevated concentrations of carbon dioxide caused by regional upwelling, to study the resilience of the reefs and survey the scale of coral cementation.

Unsurprisingly, they found that reef structures in waters with high CO2 concentrations have the lowest degree of reef cementation and appear more susceptible to erosion. Reefs exist because corals are able to build their skeletal structures faster than the rate of erosion, but if CO2 levels continue to rise, ocean acidification may slow this production and allow erosion to takeover.

For more on climate change, see http://oceana.org/climate.

[Image of eroded reef: T.B. Smith via http://dsc.discovery.com]


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