Interannual Variability of Primary Production and Carbon Fluxes on Northeast North American Shelf: Sensitivity to Climate Change?

Bronwyn Cahill, IMCS, Rutgers University, bronwyn@marine.rutgers.edu (Presenter)
Katja Fennel, Dalhousie University, katja.fennel@dal.ca
John Wilkin, IMCS, Rutgers University, wilkin@marine.rutgers.edu

The role of continental shelf systems as a sink or source of atmospheric CO₂ in global carbon budgets is an open question. Current thinking suggests that some of the factors influencing shelf ecosystem production include variability in atmospheric forcing. We investigate the impact of interannual variability in atmospheric forcing on shelf production and the capacity of different shelf regions to act as a sink or source of atmospheric CO₂. We present results from a biogeochemical model experiment along the US East Coast Continental Shelf (USECoS) and compare the shelf response using two model scenarios. The first scenario, referred to as “present day” represents contemporary mesoscale variability in forcing as captured by NARR-NCEP 3-hourly fields from 2004 to 2007. The second scenario, referred to as “future”, adjusts the present day forcing to account for atmospheric anomalies derived from modern and future simulations of a regional climate model, RegCM3, indicative of a doubling of atmospheric CO₂. Our present day interannual estimates of primary production agree well with satellite estimates. A clear along shelf gradient (south to north) in CO₂ flux is present. The South Atlantic Bight acts as a small source of CO₂ to the atmosphere, and to a lesser extent some coastal areas of the Mid-Atlantic Bight, while the Mid-Atlantic Bight Shelf and Slope waters and the Gulf of Maine act as stronger sinks of atmospheric CO₂. The response to “future” perturbations in atmospheric forcing shows interesting changes in regional production estimates. Annual production decreases in the South and Mid Atlantic Bights, while it increases in the Gulf of Maine and regional regime shifts occur in air-sea CO₂ fluxes (i.e. CO₂ sink to CO₂ source).

Presentation Type:  Poster

Session:  Coupled Processes at Land-Atmosphere-Ocean Interfaces   (Mon 4:00 PM)

Associated Project(s): 

• Friedrichs, Marjy: Impacts of Changing Climate and Land Use on Carbon Cycling and Budgets of the Coastal Ocean Margin: Observations, Analysis, and Modeling ...details

Poster Location ID: 11