Department of Biology, University of Waterloo, Waterloo, ON, N2L 3G1, Canada.
Department of Chemistry, Carleton University, Ottawa, ON, K1S 5B6, Canada.
Nat Commun. 2023 Nov 16;14(1):7402. doi: 10.1038/s41467-023-43129-x.
Landfills generate outsized environmental footprints due to microbial degradation of organic matter in municipal solid waste, which produces the potent greenhouse gas methane. With global solid waste production predicted to increase substantially in the next few decades, there is a pressing need to better understand the temporal dynamics of biogeochemical processes that control methane cycling in landfills. Here, we use metagenomic approaches to characterize microbial methane cycling in waste that was landfilled over 39 years. Our analyses indicate that newer waste supports more diverse communities with similar composition compared to older waste, which contains lower diversity and more varied communities. Older waste contains primarily autotrophic organisms with versatile redox metabolisms, whereas newer waste is dominated by anaerobic fermenters. Methane-producing microbes are more abundant, diverse, and metabolically versatile in new waste compared to old waste. Our findings indicate that predictive models for methane emission in landfills overlook methane oxidation in the absence of oxygen, as well as certain microbial lineages that can potentially contribute to methane sinks in diverse habitats.
垃圾填埋场由于城市固体废物中有机物的微生物降解而产生巨大的环境足迹，这会产生强效温室气体甲烷。随着未来几十年全球固体废物产量预计会大幅增加，迫切需要更好地了解控制垃圾填埋场甲烷循环的生物地球化学过程的时间动态。在这里，我们使用宏基因组学方法来描述在填埋场填埋 39 年的废物中的微生物甲烷循环。我们的分析表明，与旧废物相比，新废物中支持更多具有相似组成的多样化群落，而旧废物则具有更低的多样性和更多样化的群落。旧废物主要包含具有多功能氧化还原代谢的自养生物，而新废物则主要由厌氧发酵菌主导。与旧废物相比，新废物中的产甲烷微生物在丰度、多样性和代谢多功能性方面都更高。我们的研究结果表明，在没有氧气的情况下，预测垃圾填埋场甲烷排放的模型会忽略甲烷氧化，以及某些可能有助于不同生境甲烷汇的微生物类群。
