Georgia Institute of Technology Ocean Science and Engineering - OSE

The effects of climate change on the coastal ocean include a decrease in riverine inputs and increase in salinity in estuaries with impacts on primary production, macrofauna, and sediment biogeochemistry that are poorly understood. One clear effect of the increase in salinity associated with the decrease in riverine discharge, however, is the enhanced coagulation of inorganic material further upriver. Flocculation of particulate material upriver will enhance its flux to the sediment and simultaneously decrease the outflux of particulate material to the continental shelf. Any trace metal contaminant brought to the coast via riverine inputs will be trapped in these particles and accumulated in the sediment where they may constitute a threat to estuarine ecosystems, including the shellfish industry, as crabs, shrimp, and oysters will be potentially affected by the release of trace metals into overlying waters upon dissolution of the carrying particles. This project will investigate how an increase in trace metal release from sediments may affect the metal content of oysters and oyster recruitment, as the oyster industry in Georgia has been recently revitalized. Field studies that investigate the metal content of animals on the coast and relate it to salinity and geochemical conditions in the underlying sediments will be conducted seasonally to investigate the role of sediment biogeochemistry on the flux of metals from the sediment-water interface. In addition, mesocosms will be set up to reproduce the effect of trace metal inputs in the overlying waters on animal growth and stress gene expression. This research will reveal the interplay between trace metal contaminations and sediment biogeochemistry on the growth of ecologically and commercially important benthic invertebrates.