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The carbon budget of tidal wetlands and estuaries of the contiguous United States: a synthesis approach

Raymond Najjar, The Pennsylvania State University, (Presenter)
Tom Bianchi, U of Florida,
Jose D. Fuentes, Pennsylvania State University,
Maria Herrmann, Penn State University,
Wei-Jun Cai, University of Delaware,
Rusty A Feagin, Texas A&M University,
William Michael Kemp, University of Maryland,
Kevin Kroeger, USGS,
Maria A. Tzortziou, CCNY City University of New York/ GSFC-NASA,
Simone Alin, NOAA Pacific Marine Environmental Laboratory,
Chuanmin Hu, University of South Florida,
Wiley Evans, University of Alaska Fairbanks,

Tidal wetlands and estuaries play key roles in the global carbon cycle because of their high rates of carbon burial and processing of riverine carbon. A NASA-supported coastal carbon data synthesis activity, which led to the development of preliminary coastal carbon budgets for North America, identified carbon fluxes in tidal wetlands and estuaries as an area of particularly large uncertainty. The main objective of the proposed work is to develop a carbon budget for tidal wetlands and estuaries of the contiguous US using existing field observations, remote sensing products, and statistical models. The great spatial and temporal heterogeneity of tidal systems demands novel techniques for extrapolating limited in situ data to regional scales. We propose to use NASA remote sensing products as a key resource for spatially interpolating and scaling up in situ carbon data.

We seek to determine the carbon fluxes across and between the head of tide and the seawater boundary for 139 of the estuarine-wetland systems delineated and catalogued by NOAA, which account for >90% of estuarine surface area within the contiguous US. Mass-balance equations describing the steady-state organic and inorganic carbon budgets applied to tidal wetlands and estuaries are the theoretical underpinning of the analysis. The relevant carbon fluxes are the net carbon dioxide uptake from the atmosphere by tidal wetlands; the net evasion of carbon dioxide from estuaries; input from land to tidal wetlands and estuaries; burial in tidal wetland soils and estuarine sediments; the net advective transport from tidal wetlands to estuaries, tidal wetlands to the ocean, and estuaries to the ocean; and net ecosystem production in tidal wetlands and estuaries. Specifically, we propose to develop estuarine and tidal wetland databases on carbon fluxes or measurements that allow the computation of carbon fluxes. Those fluxes will be modeled using NASA remote sensing products, data from the National Wetlands Inventory, and estuarine characteristics compiled by NOAA. These models, with well-determined error estimates, will be used to extend flux estimates to all 139 systems of interest, thereby enabling the development of regional and national coastal carbon budgets.

Particular research questions we will answer with our synthesis are: Is the oxidation of organic carbon in estuaries largely supported by wetland production and export or by the respiration of riverine organic carbon? How do flux processes vary between climatic zones, and between passive margins (Atlantic, Gulf) and active margins (Pacific)? What estuaries have the highest potential for “blue carbon” projects to conserve net CO2 uptake by tidal wetlands? Is the combined system (tidal wetlands and estuaries) a net source or sink of CO2 to the atmosphere? This project has recently begun and hence initial results will be presented.

Presentation Type:  Poster

Session:  Theme 2: Landscapes to coasts: understanding Earth system connections   (Mon 1:30 PM)

Associated Project(s): 

  • Najjar, Raymond: The carbon budget of tidal wetlands and estuaries of the contiguous United States: a synthesis approach ...details

Poster Location ID: 172


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