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Microbial Abundances Predict Methane and Nitrous Oxide Fluxes from a Windrow Composting System
Shuqing Li1, Lina Song2, Xiang Gao2
1Jiangsu Key Laboratory of Low Carbon Agriculture and GHGs Mitigation, College of Resources and Environmental Sciences, Nanjing Agricultural UniversityNanjing, China; Jiangsu Key Laboratory and Engineering Center for Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing Agricultural UniversityNanjing, China.
Frontiers in Microbiology
|April 5, 2017
Summary
Manure composting releases potent greenhouse gases methane (CH4) and nitrous oxide (N2O). Bacterial gene abundances, influenced by compost conditions, significantly regulate these gas emissions, offering predictive insights.
Area of Science:
- Environmental Microbiology
- Biogeochemistry
- Agricultural Science
Background:
- Manure composting is a major source of atmospheric methane (CH4) and nitrous oxide (N2O), potent greenhouse gases.
- These emissions are mediated by specific microbial communities, including methanogens, methanotrophs, nitrifying, and denitrifying bacteria.
Purpose of the Study:
- To investigate the hypothesis that the abundance of bacterial functional genes regulates greenhouse gas fluxes during manure composting.
- To quantify the relationship between microbial gene abundances and CH4 and N2O emissions in windrow composting systems.
Main Methods:
- Simultaneous measurement of CH4 and N2O fluxes using the chamber method.
- Quantification of key functional genes (mcrA, pmoA, amoA, narG, nirK, nirS, norB, nosZ) using molecular techniques.
- Statistical analysis, including stepwise regression, to identify predictors of gas fluxes.
Main Results:
- Physicochemical parameters influenced bacterial functional gene abundances.
- CH4 and N2O fluxes were significantly correlated with the abundances of specific microbial genes.
- Pile temperature, mcrA, and NH4+ abundance best predicted CH4 fluxes.
- A model integrating nirK, nosZ, and pmoA gene abundances effectively explained N2O flux dynamics.
Conclusions:
- Bacterial functional gene abundances are key regulators of greenhouse gas emissions from manure composting.
- Developed models show applicability in predicting CH4 and N2O flux responses to environmental changes.
- Microbial gene abundances can serve as valuable indicators in carbon and nitrogen biogeochemical models.