Microbial Abundances Predict Methane and Nitrous Oxide Fluxes from a Windrow Composting System

Abstract

Manure composting is a significant source of atmospheric methane (CH4) and nitrous oxide (N2O) that are two potent greenhouse gases. The CH4 and N2O fluxes are mediated by methanogens and methanotrophs, nitrifying and denitrifying bacteria in composting manure, respectively, while these specific bacterial functional groups may interplay in CH4 and N2O emissions during manure composting. To test the hypothesis that bacterial functional gene abundances regulate greenhouse gas fluxes in windrow composting systems, CH4 and N2O fluxes were simultaneously measured using the chamber method, and molecular techniques were used to quantify the abundances of CH4-related functional genes (mcrA and pmoA genes) and N2O-related functional genes (amoA, narG, nirK, nirS, norB, and nosZ genes). The results indicate that changes in interacting physicochemical parameters in the pile shaped the dynamics of bacterial functional gene abundances. The CH4 and N2O fluxes were correlated with abundances of specific compositional genes in bacterial community. The stepwise regression statistics selected pile temperature, mcrA and NH4+ together as the best predictors for CH4 fluxes, and the model integrating nirK, nosZ with pmoA gene abundances can almost fully explain the dynamics of N2O fluxes over windrow composting. The simulated models were tested against measurements in paddy rice cropping systems, indicating that the models can also be applicable to predicting the response of CH4 and N2O fluxes to elevated atmospheric CO2 concentration and rising temperature. Microbial abundances could be included as indicators in the current carbon and nitrogen biogeochemical models.

Effect of green waste and lime amendments on biostabilisation, physical-chemical and microbial properties of the composted fine fraction of residual municipal solid waste

“…Levels of AOB gene copies were lower than those seen in studies of agricultural waste compost, where they ranged from log 8–10 g −1 at the start of composting (though decreased to undetectable levels by the end of composting) (Zeng et al, 2011). Another study, of manure composts, found lower AOB gene copy numbers (log 2.5–4.5 g −1 DM) that increased over time (Li et al, 2017), as seen in this study.…”

Influence of elevated carbon dioxide concentrations on methane emission and its associated soil microflora in rice ecosystem

“…The total methane emission increase was to the tune of 28. . This period generally corresponds with increased availability of root sloughing or exudates due to peak photosynthetic activity and advanced root senescence and might probably provide more substrate for methanogenesis (Allen et al, 2003;Tokida et al, 2010;Li et al, 2017). The results from the present experiment also demonstrated that nitrogen fertilization increased the methane flux irrespective of [CO 2 ].…”

Impact of Peat Mining and Restoration on Methane Turnover Potential and Methane-Cycling Microorganisms in a Northern Bog

“…Structural genes appear to correlate well to the activity catalyzed by the respective encoded enzymes, as has been shown for methanogenesis and methane oxidation (41)(42)(43)(44), as well as other microbe-mediated processes, e.g., 2-methyl-4-chlorophenoxyacetic acid, an herbicide, degradation (45), and N-cycling processes (46). Determining the gene abundances before and after incubation, we relate the magnitude change in the mcrA and pmoA genes to the total methane produced and oxidized, respectively (Fig.…”