Sunday, August 21, 2016

Acid attack -- can mussels hang on for much longer?

Public Release: 5-Jul-2016
Acid attack -- can mussels hang on for much longer?
Society for Experimental Biology

Scientists from The University of Washington have found evidence that ocean acidification caused by carbon emissions can prevent mussels attaching themselves to rocks and other substrates, making them easy targets for predators and threatening the mussel farming industry.

"A strong attachment is literally a mussel's lifeline" says Professor Emily Carrington, one of the lead researchers. Mussels attach themselves to hard surfaces so that they can filter plankton from seawater for food. They generally live in tidal zones, where the strong waves and currents protect them from predators such as crabs, fish and sea stars. But if a mussel falls off its perch, it sinks down into calmer waters where it is readily eaten.

Future conditions may make it more difficult for mussels to attach themselves out of harm's way. This is because the pH level appears to be critical during the attachment process, and our oceans are becoming more acidic from absorbing CO2 emissions from the atmosphere. "Our early laboratory studies showed mussels made weaker attachment threads when seawater pH dropped below 7.6" says Professor Carrington. These results could have severe implications for aquaculture. In mussel farms, the mussels attach themselves to ropes suspended in the water for 6-12 months while they grow to market size. Currently, weak attachments can cause up to 20% of the crop to fall off and be lost on the seafloor.

The researchers have shown that the change in pH specifically affects the adhesive plaque which cements the mussel to the underlying surface.


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