American Geophysical Union Become an AGU Member
Subscribe to AGU Journals		 AGU Home AGU Publications

Subscriber Access to Full Article (Nonsubscribers may purchase for $9.00, Includes print PDF, file size: 198933 bytes)

JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 106, NO. C12, PAGES 31,227–31,238, 2001

A steady state model of particulate organic carbon flux below the mixed layer and application to the Joint Global Ocean Flux Study

Alexandria B. Boehm

Department of Chemical and Biochemical Engineering and Material Science, University of California, Irvine, California


Stanley B. Grant

Department of Chemical and Biochemical Engineering and Material Science, University of California, Irvine, California


Abstract

The downward flux of particulate organic carbon (POC) through the ocean is controlled by a complex coupling of physical and biological processes. Here we analyze the equation that describes steady state coagulation, fragmentation, sedimentation, and grazing of POC below the mixed layer. The analysis yields a set of conditions under which vertical flux of POC is uncoupled from coagulation and fragmentation. When these conditions are satisfied, the model predicts that the flux of POC decays exponentially with depth down to 200–500 m, below which the flux is constant. From the magnitude of the terminal flux an estimate for the in situ clearance rate (volume swept clear of prey per grazer per unit time) for the grazer community can be obtained. This in situ clearance rate is estimated for five oceanic field sites using data collected during the Joint Global Ocean Flux Study, and the resulting values compare favorably to previously published laboratory estimates. These results suggest that, in some cases, bacterial mineralization may not be needed to explain the decline in POC flux in the mesopelagic zone of the ocean. © 2001 American Geophysical Union

Index Terms: 1615 Global Change: Biogeochemical processes (4805); 4203 Oceanography: General: Analytical modeling; 4806 Oceanography: Biological and Chemical: Carbon cycling.

Subscriber Access to Full Article (Nonsubscribers may purchase for $9.00, Includes print PDF, file size: 198933 bytes)

Citation: Boehm, A. B., and S. B. Grant (2001), A steady state model of particulate organic carbon flux below the mixed layer and application to the Joint Global Ocean Flux Study, J. Geophys. Res., 106(C12), 31,227–31,238.