Sources of Calcium for Shell of Ostrea virginica

Abstract

THE letter by Robertson and Pantin on "Tube Formation in Pomtoceros triqueter (L)"¹ points to the sea water as the source of the calcium required for the building of tubes. It is of interest that a similar condition apparently obtains in the case of Ostrea virginica. My observations in 1932–33² on the growth of oysters in Long Island Sound show that the deposition of the shell material continues throughout the winter even when other activities of the organism are reduced to the minimum. The weight of the shell increased when the temperature of the water dropped below 4° C. and the oysters were in a state of hibernation, unable to take in any food. During the same period the weight of the tissues remained constant. In view of the fact that there is no storage of calcium in the body of the oyster, an inference can be made that calcium and other salts required for the building of shells are taken in directly from the sea water.