Science Serving Maryland's Coasts

Ryan Steenson, South Dakota State University

Class Year: 

Project Title: 

Effects of Acidification on Shell Dynamics in the Eastern Oyster (Crassostrea virginica)


We determine the dissolution rate of three different types of eastern oyster shell as well as determining the growth rate of spat on different substrates under four different pH levels reflective of estuarine conditions in the Chesapeake Bay. Wet weights were taken every three days to determine dissolution rates of fresh, fossil, and weathered shell by loss of mass. To determine oyster growth rate pictures were taken of spat on PVC and fossil shell every three days and linear measurements. We found that both pH and shell type had a significant effect on dissolution rate of non living oyster shell, (F3,48 = 9.67, P < 0.0001) and (F2,48 = 17.86, P < 0.0001) respectively. The difference in dissolution was likely due to variations in surface characteristics of the shell. Oyster growth rate decreased with increasing acidity and a difference was seen in the growth rates between treatments. Our experiments illustrate that increasing acidity has the potential to decrease lifetime of oyster shell in the estuary. Furthermore, oyster growth on shell versus PVC were found to be higher under lower pH, with the implications that growing oysters can grow under acidic conditions if there they are attached to a calcium carbonate substrate.