Date of Award

Winter 2012

Project Type


Program or Major

Earth Sciences: Oceanography

First Advisor

Linda Kalnejais

Second Advisor

Jonathan Pennock

Third Advisor

Diane Foster


The role of cohesive sediments as a source of nutrients and metals to the Great Bay Estuary, NH was investigated by analyzing the porewater of several sediment cores obtained from three fields sites. Contaminant fluxes were compared between several release mechanisms including: molecular diffusion calculated from porewater profiles, bioturbation during core incubations, and sediment resuspension under simulated erosion. Ammonium, phosphate, silica, and nitrate accumulation in porewater lead to diffusive fluxes of 0.3-2, 0-0.5, 0.3-2, and -0.1-0.1 mmol m~2 day-1 respectively. Fluxes from bioturbation were on the same order of magnitude. Under simulated erosion, nutrient fluxes were over an order of magnitude greater than predicted from advection of eroded porewater. In several cases the first particles to be eroded were enriched in trace metals over bulk sediment concentrations. Total sediment fluxes from these processes are comparable to riverine inputs, thus must be accounted for when quantifying contaminant budgets to the Great Bay.