Methane production and its fate in paddy fields IV. sources of microorganisms and substrates responsible for anaerobic methane oxidation in subsoil

Methane production and its fate in paddy fields

“…There was no difference in the methane content in the leachate between Treatments 2 and 4 in the late stage of incubation. Similar results were reported in the case of methane oxidation in the subsoil Murase and Kimura 1994). These observations suggest that anaerobic methane oxidation in paddy soil may be limited.…”

“…These results indicated that methane consumption occurred under anaerobic conditions. It is considered that methane was produced in strongly reductive sites rich in organic matter such as rice straw, and that the leached methane was oxidized in relatively oxidative sites, although the sites were anoxic as well as the subsoil Murase and Kimura 1994). This assumption may also apply to the fate of methane in the plow layer of paddy fields.…”

Anaerobic oxidation of methane: an underappreciated aspect of methane cycling in peatland ecosystems?

“…Beal et al (2011) demonstrated that AOM could proceeed at SO 2− 4 concentrations <1 mM, but at that concentration AOM became uncoupled from SR. Past studies have suggested that AOM linked to SR occurs in flooded paddy soils (e.g. Murase and Kimura, 1994b), and Grossman et al (2002) reported possible AOM in a landfill leachate plume that was likely associated with SR, but these studies used mass balance approaches and did not provide direct evidence. Smemo and Yavitt (2007) found significant reductions in net CH 4 flux with additions of SO 2− 4 , but the effect was associated with suppression of gross CH 4 production and not AOM stimulation.…”

“…Other authors proposed this mechanism as well (e.g. Daniel et al, 1999;Murase and Kimura, 1994b), but, besides circumstantial evidence from rice paddies (Miura et al, 1992), the only supporting data is from marine sediments (Beal et al, 2009 where Fe reduction accounted for 27-72% of anaerobic C mineralization in fens receiving exogenous Fe and 7% with only internally cycled Fe. In a further study in the same peatlands , Fe reduction was a significant process that inhibited methanogenesis.…”

“…Panganiban et al, 1979;Smith et al, 1993;Eller et al, 2005), two landfills (Bjerg et al, 1995;Grossman et al, 2002), anoxic waste slurries (Malek and Weismann, 1988), a contaminated aquifer (Smith et al, 1991), and flooded-rice paddies (Miura et al, 1992;Murase and Kimura, 1994b), but much of the evidence is anecdotal in nature and strong evidence for AOM in freshwater systems has been limited. Work by Islas-Lima et al (2004) and Raghoebarsing et al (2006) has demonstrated that AOM in some freshwater systems is linked to denitrification and dentrifying bacteria, which provides an energetically favorable alternative to marine AOM linked to SR. Further work has suggested that AOM can be carried out by denitrifying bacteria in the absence of an archeal consortium (Ettwig et al, 2008) and that this process might be linked to nitrite (NO − 2 ) reduction and the production of oxygen (O 2 ) as an electron acceptor ; hence, implying aerobic metabolism under anoxic conditions.…”