Acidifying Oceans Dramatically Stunt Growth Of Shellfish

Research was done on the effects of increased acidic levels on growth of the Olympia oyster. Brian Gaylord, a biological oceanographer of the University of California at Davis, says that one-third of the world's human caused carbon dioxide emissions have entered the oceans. Increasing levels of carbon dioxide cause the seawater to become more acidic.

Gaylord is investigating the effects of this acidic change on the growth of larval and juvenile Olympia oysters on the west coast. He collected adult oysters from Tomales bay, California and kept them until they released larvae. The larvae were reared in one of three environments. The first matched current carbon dioxide levels which is 380 ppm. The second was 540 ppm and the third was 970 ppm. These levels are the estimated carbon dioxide levels for the year 2100.

At day 9, oyster juveniles in the high carbon dioxide treatment had shells that were 16% smaller than those reared in the control. At day 19, the results were more intense. Juveniles of the higher carbon dioxide treatment had grown 41% less than those of the control. Even after the high carbon dioxide treated oysters were placed into current water conditions for a month and a half, they were still 28% smaller.

The increasing levels of carbon dioxide in the oceans could have detrimental effects on the populations of oysters around the world. 85% of global shellfish reefs have been lost making it one of the most severely threatened marine habitats on the planet. These organisms are the engineers of bays and estuaries and with their loss will come the loss of whole ecosystems.

The article can be found here