Details:

Journal Title:
Global Biogeochemical Cycles
Personal Author:
Laufkötter, C. ; John, Jasmin G. ; Stock, Charles A. ; Dunne, John P.
Laufkötter, C. ; John, Jasmin G. ; Stock, Charles A. ; Dunne, John P. Less -
NOAA Program & Office:
OAR (Oceanic and Atmospheric Research) ; CICSP (Cooperative Institute for Climate Science) ; GFDL (Geophysical Fluid Dynamics Laboratory)
OAR (Oceanic and Atmospheric Research) ; CICSP (Cooperative Institute for Climate Science) ; GFDL (Geophysical Fluid Dynamics Laboratory) Less -
Description:
Accurate representation of the remineralization of sinking organic matter is crucial for reliable projections of the marine carbon cycle. Both water temperature and oxygen concentration are thought to influence remineralization rates, but limited data constraints have caused disagreement concerning the degree of these influences. We analyze a compilation of particulate organic carbon (POC) flux measurements from 19 globally distributed sites. Our results indicate that the attenuation of the flux of particulate organic matter depends on temperature with a Q(10) between 1.5 and 2.01, and on oxygen described by a half-saturation constant between 4 and 12 mu mol/L. We assess the impact of the temperature and oxygen dependence in the biogeochemistry model Carbon, Ocean Biogeochemistry, and Lower Trophics, coupled to Geophysical Fluid Dynamics Laboratory's Earth System Model ESM2M. The new remineralization parameterization results in shallower remineralization in the low latitudes but deeper remineralization in the high latitudes, redistributing POC flux toward the poles. It also decreases the volume of the oxygen minimum zones, partly addressing a long-standing bias in global climate models. Extrapolating temperature-dependent remineralization rates to the surface (i.e., beyond the depth range of POC flux data) resulted in rapid recycling and excessive surface nutrients. Surface nutrients could be ameliorated by reducing near-surface rates in a manner consistent with bacterial colonization, suggesting the need for improved remineralization constraints within the euphotic zone. The temperature and oxygen dependence cause an additional 10% decrease in global POC flux at 500 m depth, but no significant change in global POC flux at 2000 m under the RCP8.5 future projection.
Source:
Global Biogeochemical Cycles, 31(7), 1038-1050.
DOI:
https://doi.org/10.1002/2017gb005643
Document Type:
Journal Article
Funding:
Grant no. NA14OAR4320106
Rights Information:
Other
Compliance:
Submitted
Main Document Checksum:
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urn:sha256:d41653d1085e6d9fb76d360025346e4a78510f0dede537873d1789a5818c444e
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