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Methane Production and Oxidation in an Anoxic Rice Soil as Influenced by Inorganic Redox Species
Author(s) -
Kumaraswamy S.,
Ramakrishnan B.,
Sethunathan N.
Publication year - 2001
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2001.2195
Subject(s) - anaerobic oxidation of methane , chemistry , redox , anoxic waters , methane , environmental chemistry , anaerobic exercise , electron acceptor , sulfate , inorganic chemistry , nitrate , nitrogen , photochemistry , organic chemistry , biology , physiology
ABSTRACT The effects of addition of inorganic redox substances (species of NO − 3 , Mn 4+ , Fe 3+ , and SO 2− 4 ) on methane production and oxidation in anoxic rice ( Oryza sativa L.) soil samples were examined. Sulfate was the most inhibitory for methane production followed by Fe 3+ , NO − 3 , and Mn 4+ , in that order. Addition of rice straw at a rate of 1% (w/w) as a carbon source to increase the electron donor to the electron acceptor ratio did not completely alleviate the inhibitory effects of redox species on methane production. Interestingly, laboratory incubation studies showed that addition of MnO 2 and K 2 SO 4 enhanced aerobic methane oxidation in soil samples held at 60% water holding capacity. The suspensions of pretreated soil samples with different redox species, when tested for their ability to oxidize methane in soil solution equivalent medium supplemented with respective redox species under aerobic and anaerobic conditions showed differential effects of redox species. Nitrate and Fe 3+ stimulated methane oxidation under anaerobic conditions and retarded it under aerobic conditions. Manganese(IV) ion retarded methane oxidation under anaerobic conditions, but enhanced it under aerobic conditions. However, SO 2− 4 stimulated methane oxidation in soil solution equivalent medium under both aerobic and anaerobic conditions.