Methane production and sulfate reduction in an anoxic marine sediment
This study is the first comprehensive examination of the depth distribution of rates of methane production and sulfate reduction and the seasonal variability of these rates in an anoxic marine sediment. In organic-rich marine muds with high sedimentation rates, sulfate reduction becomes the principal electron acceptor for carbon oxidation, following exhaustion of oxygen, metal oxides and nitrate very near the sediment/water interface. In Cape Lookout Bight, North Carolina, the principal site for this study, dramatic sulfate depletion begins immediately at the interface, with the 1 mM SO/sub 4/ = isopleth found at depths shallower than 10 cm in the summer and between 20 and 30 cm in the winter. In the surficial sediments (0-5 cm) the sulfate reduction rates typically range from less than 0.3 mmol SO/sub 4/ = reduced per liter of wet sediment per day in winter to more than 2.0 mM.d/sup -1/ in summer. Also in summer a subsurface maximum in sulfate reduction occurs at approximately 9 cm depth with rates of the same order as those measured near the sediment surface. This depth is about 6 cm above the observed peaks of methane production rates. Depth-integrated rates, determined by /sup 35/SO/sub 4/ = tracer incubation, range seasonally from 6 to 70 moles m/sup -2/y/sup -1/, agreeing very well with modelled rates calculated from sulfate concentration gradients and independently determined apparent whole sediment diffusion coefficients. Rates of H/sub 2//sup 35/S from /sup 35/SO/sub 4/ = agree with 25-35% of rates determined by sulfate depletion in incubated sediment packed tubes.
- Research Organization:
- North Carolina Univ., Chapel Hill (USA)
- OSTI ID:
- 5350799
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
METHANE
RECOVERY
SULFATES
REDUCTION
ANOXIA
DEPTH
HYDROGEN SULFIDES
LABELLED COMPOUNDS
NORTH CAROLINA
SEASONAL VARIATIONS
SEDIMENTS
SULFUR 35
TRACER TECHNIQUES
ALKANES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CHALCOGENIDES
CHEMICAL REACTIONS
DAYS LIVING RADIOISOTOPES
DIMENSIONS
EVEN-ODD NUCLEI
FEDERAL REGION IV
HYDROCARBONS
HYDROGEN COMPOUNDS
ISOTOPE APPLICATIONS
ISOTOPES
LIGHT NUCLEI
NORTH AMERICA
NUCLEI
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
RADIOISOTOPES
SULFIDES
SULFUR COMPOUNDS
SULFUR ISOTOPES
USA
VARIATIONS
090122* - Hydrocarbon Fuels- Preparation from Wastes or Biomass- (1976-1989)