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Contemporary and projected lateral carbon fluxes from North America to Oceans: A process-based modeling study

Hanqin Tian, Auburn University, (Presenter)
Qichun Yang, Auburn University,
Wei Ren, Auburn University,
Chaoqun Lu, Auburn University,
Bowen Zhang, Auburn University,
Shufen Pan, Auburn University,
Steven Lohrenz, University of Massachusetts Dartmouth,
Wei-Jun Cai, University of Delaware,
Ruoying He, North Carolina State University,
Marjorie Friedrichs, Virginia Institute of Marine Science,
Raymond Najjar, The Pennsylvania State University,

The lateral carbon (C) flux from land to ocean is an important component of the global carbon budget, but less constrained. The magnitude and spatiotemporal patterns of lateral carbon fluxes from land to oceans and the underlying mechanisms responsible for these fluxes are far from certain. Here we applied a process-based land model with explicit representation of carbon processes in stream and rivers (Dynamic Land Ecosystem Model: DLEM) to examine how changes in climate, land use, management practices, atmospheric CO2, and nitrogen deposition have affected the carbon fluxes from North American (NA) continent to Oceans in the past three decades, and further to project potential riverine carbon fluxes under future climate scenarios. For the contemporary period, we estimated the mean annual fluxes of dissolved organic carbon (DOC) and dissolved inorganic carbon (DIC) over 1980-2010 across the entire NA region and five subregions; and conducted model performance evaluation. For future projection, we particularly investigated the potential changes in riverine carbon fluxes from the Gulf of Mexico and the Atlantic subregions in the 21st century. Our preliminary results show that: 1) Annual total dissolved C export from North America was 96.1 Tg C/yare as estimated by DLEM; DIC, DOC were 33.6 Tg C/yare and 62.5 Tg C/yare, respectively.

2) Annual dissolved C export from NA was about 18.8% of terrestrial C sink and 38.8% for carbon sink of the forest sector (relative to the terrestrial C sink estimates by Hayes et al., 2012). 3) Carbon fluxes from the Arctic subregion showed increasing trends, whereas DOC and DIC export to the Gulf of Mexico decreased from 1980 to 2010. Large uncertainty exists in current C export estimates resulted from input data, model structure and parameters. Simulations need to be improved in the future.

Presentation Type:  Poster

Session:  Carbon Monitoring System (CMS) Posters   (Mon 1:30 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
  • Hofmann, Eileen: Impacts of Changing Climate and Land Use on Carbon Cycling and Budgets of the Coastal Ocean Margin: Observations, Analysis, and Modeling ...details
  • Lohrenz, Steve: An Integrated Terrestrial-Coastal Ocean Observation and Modeling Framework for Carbon Management Decision Support ...details

Poster Location ID: 207


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