Mechanisms That Regulate The Intensity Of Oxidation-Reduction In Anaerobic Sediments And Natural Water Systems
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Date
1978-08
Authors
Brannon, James M.
Gunnison, Douglas
Butler, Patricia L.
Smith, Issac Jr.
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Abstract
A literature review and a series of laboratory experiments were conducted
to investigate the mechanisms that regulate the intensity of oxidation-reduction
in natural environments. Results of the literature review indicated
that following depletion of oxygen and nitrate, the highly reduced conditions
reached by systems containing substantial amounts of organic matter appear to
involve mixed potentials generated by unknown organic oxidation-reduction
couples that act in concert with inorganic oxidation-reduction couples. Results of the laboratory studies confirmed that organic oxidation-reduction couples
of an unknown nature were exerting a strong influence on Eh. The iron and manganese oxidation-reduction systems were also shown to be affecting Eh,
although in a manner consistent with the existence of a mixed potential.
Redox potential should only be used as a semiquantitative indicator of the intensity of reduction. Precise evaluation of the reduction status of anaerobic natural envirsnmeilts should be determined by rigorous analysis
of various chemical constituents, including manganese (IT) ,, iron (II), and sulfide. Comparism of results of the present study with those others indicated that microbial succession and appearance of reduced
products closely parallel those found in flooded soils and sediments. The appearance of reduced products corresponded to the sequence roughly
predicted by thermodynamics.
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Keywords
Mechanisms , Oxidation-Reduction , Anaerobic Sediments , Natural Water Systems