Abstract: Deposition of Atmospheric Nitrogen to Coastal Ecosystems (DANCE): A study in seasonally oligotrophic waters off the eastern U.S. (2016 Ocean Sciences Meeting)

Deposition of Atmospheric Nitrogen to Coastal Ecosystems (DANCE): A study in seasonally oligotrophic waters off the eastern U.S.

Raymond Najjar¹, Peter Sedwick², Margaret R Mulholland², Marjorie A. M. Friedrichs³, Anne M Thompson⁴, Douglas K Martins¹, Peter W Bernhardt², Maria Herrmann¹, Lynn Marrie Blumen², Bettina M Sohst², Christine Sookhdeo², Pierre St-Laurent³ and Brittany Widner², (1)Pennsylvania State University, Department of Meteorology, University Park, PA, United States, (2)Old Dominion University, Department of Ocean, Earth and Atmospheric Sciences, Norfolk, VA, United States, (3)Virginia Institute of Marine Science, Gloucester Point, VA, United States, (4)NASA Goddard Space Flight Center, Greenbelt, MD, United States

Abstract:

We carried out a program of process-oriented field measurements and biogeochemical modeling in oligotrophic coastal waters off the eastern U.S.—a region that currently receives high levels of atmospheric nitrogen deposition (AND)—to test whether wet AND events stimulate primary productivity and accumulation of algal biomass in coastal waters following summer storms. Our results from shipboard incubations and numerical modeling indicate that nitrogen in rain stimulated primary production in these waters during the summer of 2014. We will present isotopic, tracer, and modeling analyses that determine the relative roles of vertical mixing and atmospheric deposition during the wet AND events in two anticyclonic eddies north and south of the Gulf Stream. 3-D atmospheric and oceanic modeling results will also be presented, which allow the understanding gained during the summer 2014 field campaign to be applied to quantifying the role of atmospheric deposition throughout coastal waters of the eastern US over many years.

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