Microbial reduction mechanism of ferric iron in paddy soils (Part I)

Dissimilatory Fe(III) and Mn(IV) Reduction

“…Carbon dioxide production and Fe(III) reduction were highly correlated for approximately 2 weeks after flooding (339). Calculations from the paddy soil data of Kamura and co-workers (164) and Saito and Wada (275) indicated that, during the period of active Fe(III) reduction, Fe(III) reduction accounted for 35 to 65% of the organic-matter oxidation to carbon dioxide (184). Studies with a swamp soil indicated that about 50% of the total oxygen consumption in the soil could be attributed to oxidation of dissolved and solid Fe(II) (141).…”

“…Fe(III) reduction is invariably inhibited when microbial metabolism in aquatic sediments is inhibited (158,164,189,286). However, this result does not necessarily exclude the redox or direct-reduction mechanism.…”

“…The restriction of Fe(III) and Mn(IV) reduction to narrow zones near the sediment-water interface in many aquatic sediments makes determination of the in situ rates of Fe(III) and Mn(IV) reduction difficult. Rates of Fe(III) and Mn(IV) reduction in sediments have typically been estimated from the accumulation of Fe(II) and Mn(II) in anaerobic laboratory incubations of sediments (91,159,164,193,197,211,275,286). However, such measurements do not account for the fact that the supply of electron acceptors for potentially competing processes such as oxygen and nitrate reduction have been eliminated (193).…”

Effect of Leaking Natural Gas on Soil and Vegetation in Urban Areas

“…Addition of easily decomposable organic matter is found to accellerate the reduction processes (Aomine, 1962;McKeague, 1965;Gotoh & Yamashita, 1966;Harmsen, 1971). The oxidation-reduction processes are related to the rate of microbial activity (Kamura et al, 1963;Parr, 1969).…”

Stability behavior of soil colloidal suspensions in relation to sequential reduction of soils

“…Sequential reduction processes of waterlogged soil were reported to be associated with activities of a variety of microorganisms (Kamura et al 1963;Takai et al 1963a, b). During the earlier period of waterlogging, nitrate disappears first, Mn 2 + and Fe H are sequentially formed, and volatile fatty acids (VF As) also accumulate in large amounts corresponding to the activities of aerobes and facultative anaerobes.…”