Global distribution of sulfate reduction rates in marine sediments


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Sabine.Kasten [ at ] awi.de

Abstract

Sulfate is the dominant terminal electron acceptor in marine sediments. Sulfate reduction proceeds under anoxic conditions and is supported by a variety of electron donors (e.g. hydrogen, acetate, methane, propane, and butane), most of which are supplied by the decomposition of sedimentary organic matter. Consequently, a combination of primary productivity and water column depth is often thought to control sulfate reduction throughout most of the ocean’s seafloor [1, 2]. However, global models of sulfate reduction do not resolve the many different physical and ecological parameters that are encountered on a global scale, and that ultimately play a major role in driving local and regional sulfate reduction rates. We sought to better determine sulfate reduction rates on a global scale, irrespective of region or location by 1) including sulfate profiles from diverse settings and 2) compiling multiple geochemical parameters that are relevant to sulfate reduction and can help discern the magnitude of sulfate reduction rates. All available sulfate concentration profiles from DSDP/ODP/IODP (to Exp. 312) and additionally those in the database Pangaea (www.pangaea.de) were compiled reaching a total >600 nonrepetitive concentration profiles. Basic metadata describing the cores was included, such as water depth and distance to shore. Water column data such as minimum percent O2 saturation, bottom water O2, NO3 -, PO4 3-, and concentrations of surface water chlorophyll a and POC [3, 4] were included as additional variables that describe the biogeochemical setting of the cores. All compiled data and concentration profiles were applied to a training algorithm to estimate global sulfate reduction rates. The result was the most precise depiction of global sulfate reduction rates at the highest resolution to date. Our model serves as a platform for the examination of biogeochemical processes on the global scale and lets us predict energetic constraints for microbial metabolism in the subseafloor. [1] Canfield (1991) AJOS 291, 177-188. [2] Middelburg et al. (1997) DSR 44, 327-344. [3] Levitus & Boyer (1994) NOAA Atlas NESDIS [4] NASA, Aqua-MODIS



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Published
Eprint ID
34691
DOI 10.1180/minmag.2013.077.5.2

Cite as
Bowles, M. W. , Mogollón, J. M. , Kasten, S. , Zabel, M. and Hinrichs, K. U. (2013): Global distribution of sulfate reduction rates in marine sediments , Mineralogical Magazine - B: Goldschmidt Abstracts 2013, 77 (5), p. 756 . doi: 10.1180/minmag.2013.077.5.2


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