Graduation Year


Document Type




Degree Granting Department

Marine Science

Major Professor

John J. Walsh, Ph.D.


Marine ecology, Diatoms, Numerical modeling, Nutrient cycles, Phytoplankton


In some continental shelf sediments integrated benthic microalgal biomass is greater than the integrated phytoplankton biomass in the overlying water column. In addition, benthic microalgae may account for up to 10% of the primary production responsible for the coastal fishery yield of the eastern United States. A three-dimensional model of the eastern Gulf of Mexico examines the effects of water-column nutrient sources on the growth of benthic microalgae. To parameterize the exchange of nutrients across the sediment/water interface in these permeable sediments, a non-local exchange submodel was constructed and tested within the framework of the model's grid. Based on the results of the three dimensional simulations, the growth of benthic microalgae from water-column nutrients is highly dependent on the light limitation of overlying phytoplankton. When light is available to phytoplankton in high enough quantities, water-column nutrients are used up before reaching the sediments. When the overlying phytoplankton are light limited, nutrients are able to reach the sediments where the shade adapted benthic microalgae can grow.