Anaerobic mineralization of marine sediment organic matter: Rates and the role of anaerobic processes in the oceanic carbon economy

Susan M Henrichs,William S Reeburgh

doi:10.1080/01490458709385971

Susan M Henrichs, William S Reeburgh

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https://doi.org/10.1080/01490458709385971

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Journal: Geomicrobiology Journal	Publication Date: Jan 1, 1987
Citations: 486	License type: cc-by

Affiliation: University of Alaska Fairbanks

Abstract

Abstract This paper addresses three related questions: (1) What factors control the efficiency of carbon burial in sediments? (2) Are rates of anaerobic organic matter degradation intrinsically lower than aerobic rates? (3) How important are anaerobic processes in the global marine sediment carbon economy? Carbon burial efficiency (the ratio of the carbon burial rate and the carbon flux to the sediment surface) was estimated from literature data for a range of environments and was shown to be a function of sedimentation rate. No difference independent of sedimentation rate was found between aerobic and anaerobic sediments. A review of recent microcosm and laboratory studies shows that anaerobic rates are not intrinsically lower than aerobic rates; fresh organic matter degrades at similar rates under oxic and anoxic conditions. Aerobic decomposition rates near the sediment surface are typically greater than anaerobic rates at depth because the most labile carbon is consumed before it can be buried in the a...

Highlights

Aerobic oxidation of organic matter in marine sediments is generally accepted to be the most important form of respiration in most situations (Ssrensen et al 1979, Jsrgensen & Serrensen 1985, Jerrgensen & Revsbech 1989)
The most significant conclusion from this experiment is that mineralization of organic material was the same under anaerobic and aerobic conditions
The rate of anaerobic degradation has long been known (Aller 1980, Berner 1980, Santschi et al 1990), but only recently has it been established that sulfate reduction is a very efficient process (Henrichs & Reeburgh 1987, Canfield 1989, Mackin & Swider 1989)

Summary

Introduction

Aerobic oxidation of organic matter in marine sediments is generally accepted to be the most important form of respiration in most situations (Ssrensen et al 1979, Jsrgensen & Serrensen 1985, Jerrgensen & Revsbech 1989). Recent investigations have questioned this assumption (e.g.Henrichs & Reeburgh 1987, Kristensen & Blackburn 1987, Mackin & Swider 1989). Aerobic respiration takes place in the oxic surface layer and is followed by nitrate reduction and sulfate reduction. The oxic zone often is only a few millimeters thick (Revsbech et al 1980), and anaerobic respiration becomes dominant. Much of the oxygen uptake is used to reoxidate the products of anaerobic respiration (H2S,NH4+,CH4) at the oxic/anoxic interface (Jargensen 1983a, b). Hargrave & Phillips (1981) proposed that this could account for 50 O/O of overall

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Conclusion