BUDGETS OF BIOGENIC ELEMENTS IN THE NW ATLANTIC OCEAN MARGIN: A SYNTHESIS AND MODELLING PROJECT
PROJECT SUMMARY
To reduce major uncertainties in predicting future global environmental quality, it is imperative to understand the sources and sinks of atmospheric CO2, the role of anthropogenic activities in disrupting the natural carbon cycle, and the effects of, and feedbacks between, these activities and the natural carbon cycle. Within the oceans, the ocean margin carbon cycle will be the most impacted. The U.S. Department of Energy designed and implemented a field study called the Ocean Margins Program (OMP) to examine carbon cycling in the continental margin of the western North Atlantic Ocean. The central objectives of the OMP are (1) to quantify the processes and mechanisms that affect the cycling, flux, and storage of carbon and other biogenic elements at the land/ocean interface; (2) to define ocean-margin sources and sinks in global biogeochemical cycles; and (3) to determine whether ocean margins, including continental shelves, are quantitatively significant in removing carbon dioxide from the atmosphere and isolating it via burial in sediments or by export to the interior ocean, or elsewhere.
This field program resulted in the most extensive, multidisciplinary set of water column and seabed observations ever obtained over an ocean margin. However, the DOE has terminated its marine research programs prior to the planned synthesis of the OMP. In the absence of an integrated, funded, and organized data analysis, this $50M investment in ocean margin carbon fluxes would have been lost. Fortunately, a first level analysis of this extensive dataset has been funded through the JGOFS Synthesis and Modeling effort to begin to address the role of the ocean margins and rivers. In this program, we intend to complete the original OMP objectives and facilitate the incorporation of the resulting database into the analyses of the various complementary JGOFS programs. The OMP dataset specifically addresses all of the major SMP goals, complements the JGOFS oceanic databases, and thus is highly relevant to SMP programmatic goals.
BACKGROUND
Since the beginning of the Industrial Revolution, human energy-related activities have dramatically altered the global carbon cycle, and consequently, this cycle is not presently in a steady-state. To reduce major uncertainties in predicting future global environmental quality, it is imperative to understand the sources and sinks of atmospheric CO2, the role of anthropogenic activities in disrupting the natural carbon cycle, and the effects of, and feedbacks between, these activities and the natural carbon cycle. Within the oceans, the ocean margin carbon cycle will be the most impacted. Due to increased loading of nutrients to the margins, which is related to the rate of human population growth and high population densities in coastal states (Malone, 1998), biological carbon fixation has been stimulated. Depending on the fate of the fixed carbon, this stimulation has the potential to mitigate the anthropogenically derived CO2 (OMP, 1994). Determining the factors that control the magnitude of carbon exchanges between the ocean margins and the atmosphere, and the subsequent fate of this carbon, is crucial to predicting the strength and capacity of the oceans to absorb excess anthropogenic atmospheric CO2 (Walsh et al., 1985; Sabine and Mackenzie, 1991; Walsh, 1991.).
Recognizing this need, and with enthusiastic support from the U.S. JGOFS program, the U.S. Department of Energy designed and implemented a field study called the Ocean Margins Program (OMP) to examine carbon cycling in the continental margin of the western North Atlantic Ocean. The focus was primarily on the southern portion of the Mid-Atlantic Bight between Cape Hatteras and Chesapeake Bay, where a large flux of freshwater and organic carbon flows to the North Atlantic Ocean (Churchill et al. 1993; Blair et al. 1994). The OMP focused on this area after the SEEP I and II studies found that only a small fraction of the new production was exported across the shelf-slope front on the central MAB (Walsh et al. 1988; Biscaye et al. 1994).
The central objectives of the OMP are (1) to quantify the processes and mechanisms that affect the cycling, flux, and storage of carbon and other biogenic elements at the land/ocean interface; (2) to define ocean-margin sources and sinks in global biogeochemical cycles; and (3) to determine whether ocean margins, including continental shelves, are quantitatively significant in removing carbon dioxide from the atmosphere and isolating it via burial in sediments or by export to the interior ocean, or elsewhere. To achieve these objectives, an integrated multidisciplinary field program was conducted during 1993-1996 to quantify the physics and biogeochemical processes affecting carbon fluxes, nutrient cycles, and ecological dynamics in shelf and slope waters at Cape Hatteras, where carbon burial in sediments and carbon export to the interior ocean were expected to be maximal (Blair et al. 1994; Jahnke and Verity 1994). This field program resulted in the most extensive, multidisciplinary set of observations ever obtained over an ocean margin.
The central objective of the JGOFS SMP is to synthesize knowledge gained from U.S. JGOFS and related studies into a set of models that reflect the current understanding of the ocean carbon cycle and its associated uncertainties. To this end, specific SMP goals were adopted, including: (a) to synthesize knowledge of inorganic and organic carbon fluxes and inventories, both natural and anthropogenic; (b) to identify and quantify the principal processes that control the partitioning of carbon among oceanic reservoirs, and between the ocean and atmosphere on local and regional scales, with a view towards synthesis and prediction on a global scale; and (c) to determine the mechanisms responsible for spatial and temporal variability in biogeochemical processes that control partitioning of carbon among oceanic reservoirs and between the ocean and atmosphere (SMP RFP, 1998). The OMP dataset specifically addresses all three of these SMP goals, complements the JGOFS oceanic databases, and thus is highly relevant to the SMP program goals.
OMP-SMP Scientists and Collaborators
Josephine J. Aller Zbigniew S. Kolber
Robert Aller Steven E. Lohrenz
Jim Bauer Chris Martens
Larry Benninger Lawrence M. Mayer
Robert F. Chen G.-A. Paffenhofer
Mike DeGrandpre Brian Palenik
Dave DeMaster John H. Paul
Ellen R. M. Druffel Leonard J. Pietrafesa
Timothy I. Eglinton Donald G. Redalje
Paul Falkowski Clare Reimers
Charles Flagg Daniel J. Repeta
Stephen J. Giovannoni Evelyn Sherr
Tom S. Hopkins Barry Sherr
Charles S. Hopkinson, Jr Peter G. Verity
Richard A. Jahnke Douglas Wallace
Hans Jannasch Ian D. Walsh
Paul F. Kemp George Weatherly
David Kirchman Creighton Wirick
Here are some matlab programs and data files for creating maps for the southern Mid-Atlantic Bight and OMP area.
HYDROGRAPHIC DATA
Station Listings and Cruise Tracks:
MOORINGS AND TIME SERIES DATA
Click here to view the mooring array for the first deployment.
Click here to view the mooring array for the second deployment.
NEW >>> A 3-D hydrographic animation from the moorings. <<<
Click here to retrieve the animation.
OMP Satellite Images provided by North Carolina State University
