A biogeochemical model for the northwestern Atlantic continental shelf

Katja Fennel and John Wilkin
IMCS, Rutgers University

Biogeochemical processes in continental shelf systems such as shelf primary production or sediment denitrification are thought to contribute significantly to global primary production and denitrification. Shelf processes thus play an important role in the elemental cycling of nitrogen and carbon, yet shelf systems are generally not resolved in basin-wide and global biogeochemical models. We developed a high-resolution biogeochemical-physical ROMS for the northwestern Atlantic Ocean’s continental shelves and adjacent deep ocean in order to estimate shelf fluxes of nitrogen and carbon. Our biological model is a relatively simple representation of nitrogen cycling in the water column and organic matter remineralization at the water-sediment interface that explicitly accounts for sediment denitrification. Carbon and oxygen dynamics are explicitly included and are driven by the photosynthetic production and remineralization of organic matter and by air-sea exchange of CO2 and O2. Model/data comparisons using climatological nutrient, chlorophyll, primary production and denitrification data, statistical measures of pattern variability, and a nitrogen budget for the Middle Atlantic Bight will be presented. Our results emphasize the importance of representing shelf processes in biogeochemical models.