Reduction soil microorganisms

Biodegradation of fuel oils in sediments is inhibited under anaerobic conditions (Bartha and Atlas 1977). Under anaerobic conditions, some soil microorganisms are capable of nitrate reduction using fuel oils as the carbon source, although nitrite may be an unwanted by-product. However, the addition of a small amount of oxygen (0.2 volume percent oxygen) to the medium can accelerate the degradation of the oil without the concomitant production of nitrite (Riss and Schweisfurth 1987). 

Naled is practically nonpersistent in soil, with half-life of less than 1 day. It degrades in sunlight to di-chlorvos (DDVP). Naled does not bind strongly to soils, but is not highly soluble in water. It is moderately volatile. Soil microorganisms break down most of the naled in the soil. Naled is rapidly broken down in water, with a half-life of 2 days. Plants reductively eliminate bromine from naled to form DDVP, which may evaporate or be further modified. 

Soil microorganisms may also oxidize elementary Se (Sarathchandra and Watkinson, 1981 Dowdle and Oremland, 1998) to selenite and selenate. However, microbial reduction of selenite and selenate to elementary selenium is thought to be more important and is certainly investigated more than is microbial oxidation. Both bacteria and fungi (Bautista and Alexander, 1972) play roles in selenium reduction, but the former have been studied more extensively (White et al., 1995). Bacteria may reduce Se under both aerobic (Lortie et al., 1992 Garbisu et al., 1995 Dungan et al., 2003) and anaerobic conditions (Oremland... 

There is little evidence of a direct or indirect role or soil bacteria on the dynamics of Cs. Russell et al. (2004) recently reported that bacterial sulfate reduction decreased the adsorption of Cs on arid and tropical soils, but proposed no mechanism. It is unlikely that the accumulation of Cs makes soil microorganisms an important pool for immobilized Cs in mineral soils (because adsorption on soil clays would be much greater). However, this may not be the case in organic soils (Sanchez et al., 2000). 

The reductive pathways for nitrogen include NOJ and N2 reduction to amino acids in plants and in microbes. Soil microorganisms reduce nitrogen stepwise ... 

Blackmer, A. M. and J. M. Bremner. 1978. Inhibitory effect of nitrate on reduction of NjO to Nj by soil microorganisms. Soil Biol. Biochem. 10 187-191. 

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