Estuarine Export of Dissolved Organic Carbon to the Mid-Atlantic Bight

Sergio R Signorini, NASA Goddard Space Flight Center, Greenbelt, MD, United States, Antonio Mannino, NASA Goddard Space Flight Center, Ocean Ecology Laboratory, Greenbelt, United States, Marjorie A. M. Friedrichs, Virginia Institute of Marine Science, Gloucester Point, VA, United States, John Wilkin, Rutgers University, New Brunswick, NJ, United States and Aboozar Tabatabai, Rutgers University
Abstract:
Estuaries play an important role in transforming riverine nutrients and carbon before they are exported to the adjacent continental shelf. Land-estuarine-ocean biogeochemical modeling systems, evaluated with in situ and satellite data, are invaluable tools to quantify riverine nitrogen and carbon inputs, within-estuary nitrogen/carbon transformation processes and the ultimate export of nitrogen and carbon to the coastal ocean.

In this study, we developed satellite algorithms to retrieve estuarine dissolved organic carbon (DOC) concentrations, and combined these surface DOC estimates with output from physical circulation models based on the Regional Ocean Modeling System (ROMS) to quantify coastal DOC fluxes. This study specifically focuses on the export of DOC from two major estuaries, Chesapeake Bay and Delaware Bay, to the U.S. Middle Atlantic Bight (MAB) using newly developed higher resolution models. DOC profiles required to compute the tracer fluxes at the mouths of the estuaries were derived using a feed forward neural networks model trained with in situ data (salinity, temperature, and DOC).The seasonal and interannual variability of estuarine DOC export are analyzed based on multi-year model runs for Delaware Bay and Chesapeake Bay, combined with surface DOC concentrations derived from the satellite retrievals. Fluxes derived from coupled biogeochemical-circulation modeling systems are compared with these off-line model-satellite tracer fluxes. Results from this study will be used to improve the assessment of the total carbon budget for the MAB.