A COMPARISON OF CALCIUM CARBONATE SEDIMENT BUFFERS TO INCREASE THE LARVAL SETTLEMENT OF THE SOFT SHELL CLAM Mya arenaria  

Calcium carbonate in the form of aragonite and calcite is an essential constituent of shell formation in marine bivalves. As a result of natural processes, sediment pore water can become significantly undersaturated with respect to calcite and aragonite near the surface water interface (SWI). While this is a common occurrence in coastal sediments, anthropogenic changes to coastal and open ocean environments have intensified the process potentially resulting in significant impacts to bivalve populations that inhabit coastal sediments. The addition of calcium carbonate buffers to undersaturated sediments has been shown to offset these effects by increasing the aragonite saturation state, or the omega value (Ω), of interstitial waters and subsequently increase the rate of settlement of benthic bivalves. Various materials have been suggested as possible sediment buffers (shell-hash, marble chips); however, no research has directly focused on comparing the efficacy of different buffer materials and the most appropriate application concentration. In this study we compared the efficacy of four different locally available buffer materials, each at three different concentrations, to determine each buffers ability to increase the settlement and recruitment of M. arenaria and their potential as a resource enhancement methodology. Results specific buffer materials, and increased concentrations of buffer materials, have a statistically significant correlation with both the (Ω) of interstitial waters and the rate of recruitment of M. arenaria.