Wednesday, May 6, 2015

A revised global estimate of dissolved iron fluxes from marine sediments

This is also an important paper recently published on Iron-flows through marine sediments.

Denitrification, Anammox, and N2 Production in Marine Sediments

Interesting and recently published paper on Nitrogen-cycling in marine sediments!

Denitrification, Anammox, and N2 Production in Marine Sediments

Annual Review of Marine ScienceVol. 7: 403-423 (Volume publication date January 2015)DOI: 10.1146/annurev-marine-010213-135040Allan H. DevolSchool of Oceanography, University of Washington, Seattle, Washington 98195-5351; email:

Abstract: Fixed nitrogen limits primary productivity in many parts of the global ocean, and it consequently plays a role in controlling the carbon dioxide content of the atmosphere. The concentration of fixed nitrogen is determined by the balance between two processes: the fixation of nitrogen gas into organic forms by diazotrophs, and the reconversion of fixed nitrogen to nitrogen gas by denitrifying organisms. However, current sedimentary denitrification rates are poorly constrained, especially in permeable sediments, which cover the majority of the continental margin. Also, anammox has recently been shown to be an additional pathway for the loss of fixed nitrogen in sediments. This article briefly reviews sedimentary fixed nitrogen loss by sedimentary denitrification and anammox, including in sediments in contact with oxygen-deficient zones. A simple extrapolation of existing rate measurements to the global sedimentary denitrification rate yields a value smaller than many existing measurement-based estimates but still larger than the rate of water column denitrification.

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