Some ocean dwellers can increase shell production in CO2 rich environment

December 2nd, 2009 - 4:20 pm ICT by ANI  

Washington, December 2 (ANI): In a new research, scientists have found that some creatures residing in the ocean can increase shell production in a carbon dioxide (CO2) rich environment.

The research, by Woods Hole Oceanographic Institution (WHOI) scientists, found that some shell-building creatures, such as crabs, shrimp and lobsters, unexpectedly build more shell when exposed to ocean acidification caused by elevated levels of atmospheric CO2.

Because excess CO2 dissolves in the ocean-causing it to “acidify” -researchers have been concerned about the ability of certain organisms to maintain the strength of their shells.

CO2 is known to trigger a process that reduces the abundance of carbonate ions in seawater-one of the primary materials that marine organisms use to build their calcium carbonate shells and skeletons.

The concern is that this process will trigger a weakening and decline in the shells of some species and, in the long term, upset the balance of the ocean ecosystem.

But, in a new study, a team led by former WHOI postdoctoral researcher Justin B. Ries found that seven of the 18 shelled species they observed actually built more shell when exposed to varying levels of increased acidification.

This may be because the total amount of dissolved inorganic carbon available to them is actually increased when the ocean becomes more acidic, even though the concentration of carbonate ions is decreased.

“Most likely the organisms that responded positively were somehow able to manipulate dissolved inorganic carbon in the fluid from which they precipitated their skeleton in a way that was beneficial to them,” said Ries, now an assistant professor in marine sciences at the University of North Carolina.

“They were somehow able to manipulate CO2 to build their skeletons,” he added.

Organisms displaying such improvement also included calcifying red and green algae, limpets and temperate urchins.

“We were surprised that some organisms didn’t behave in the way we expected under elevated CO2,” said Anne L. Cohen, a research specialist at WHOI and one of the study’s co-authors.

“What was really interesting was that some of the creatures, the coral, the hard clam and the lobster, for example, didn’t seem to care about CO2 until it was higher than about 1,000 parts per million (ppm),” she added.

The “take-home message is that we can’t assume that elevated CO2 causes a proportionate decline in calcification of all calcifying organisms,” said Cohen. (ANI)

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