EXPERIMENTAL STUDY OF BIVALVE SHELL DISSOLUTION RATES AT VARYING WATER TEMPERATURES

The existing body of literature regarding bivalve shell dissolution focuses almost entirely on taphonomic implications for shells of varying sizes, shapes and compositions. Although it is generally accepted that dissolution of calcite and aragonite occurs more rapidly in lower-temperature waters, little attempt has been made to quantify these rates and thereby the pressure dissolution exerts on the organism in life. In the first part of the study, samples of dentition, muscle scar, inside and outside scar regions were taken from Mercenaria mercenaria, Mya arenaria, and Mytilus edulis and submerged for two months in Antarctic waters. Samples were examined before and after submersion using a dissecting microscope and a scanning electron microscope. Before and after photos of the samples were taken using the SEM and compared, in addition to general observation. After the submersion period, no effects of dissolution were observable using the methods of the study. Therefore, a laboratory study designed to compare dissolution rates by mass was set up at three water temperatures, roughly 72ºF, 38ºF, and 36-34ºF. Each container holds one Mercenaria mercenaria half shell in “instant” seawater and is circulated using an air pump. This experiment is currently in progress and, as yet, inconclusive, but any results are expected to be observed on a very small scale.