Sea cucumbers dissolve coral reefs...

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Acidifying oceans can dissolve coral reefs, but so can something that lives on them – sea cucumbers – according to research published in a recent issue of the Journal of Geophysical Research.

Kenneth Schneider and coauthors showed in this study that sea cucumbers are capable of dissolving significant portions of calcium carbonate as part of their digestive process, accounting for about half of at the total night-time calcium carbonate dissolution for the reef.

Studying the sea cucumbers Stichopus herrmanni and Holothuria leucospilota in One Tree Reef in the southern Great Barrier Reef, the authors incubated individual sea cucumbers in aquaria, measuring the total alkalinity of the water to assess the amount of calcium carbonate they dissolve during the digestion of the sand and coral rubble that pass through their gut as they feed.  Based on the measurements they obtained and results from surveys of One Tree Reef, the authors then calculated the amount of calcium carbonate dissolution caused by the two species of sea urchins.

Although the calcium carbonate dissolution may sound bad for the reef, the role of sea cucumbers is more complicated than merely acting as agents of dissolution. " sea cucumbers…can be important in recycling of nutrients to support primary productivity. They also increase sea water buffer capacity to partially offset ocean acidification effects, helping to maintain the overall health of the coral reef," senior author Kenneth Schneider said. "Although sea cucumbers may play a part in reef dissolution, they are also an important part of an incredible marine environment."

For more information, see the paper: (2011) Potential influence of sea cucumbers on coral reef CaCO3 budget: A case study at One Tree Reef. Journal of Geophysical Research 116, G04032, doi:10.1029/2011JG001755

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