Department of Biosystems Engineering and Soil Science, University of Tennessee, Knoxville, TN 37996, USA.
Department of Microbiology, University of Tennessee, Knoxville, TN 37996, USA.
FEMS Microbiol Ecol. 2024 Sep 14;100(10). doi: 10.1093/femsec/fiae119.
Human decomposition in terrestrial ecosystems is a dynamic process creating localized hot spots of soil microbial activity. Longer-term (beyond a few months) impacts on decomposer microbial communities are poorly characterized and do not typically connect microbial communities to biogeochemistry, limiting our understanding of decomposer communities and their functions. We performed separate year-long human decomposition trials, one starting in spring, another in winter, integrating bacterial and fungal community structure and abundances with soil physicochemistry and biogeochemistry to identify key drivers of microbial community change. In both trials, soil acidification, elevated microbial respiration, and reduced soil oxygen concentrations occurred. Changes in soil oxygen concentrations were the primary driver of microbial succession and nitrogen transformation patterns, while fungal community diversity and abundance was related to soil pH. Relative abundance of facultative anaerobic taxa (Firmicutes and Saccharomycetes) increased during the period of reduced soil oxygen. The magnitude and timing of the decomposition responses were amplified during the spring trial relative to the winter, even when corrected for thermal inputs (accumulated degree days). Further, soil chemical parameters, microbial community structure, and fungal gene abundances remained altered at the end of 1 year, suggesting longer-term impacts on soil ecosystems beyond the initial pulse of decomposition products.
人类在陆地生态系统中的分解是一个创造局部土壤微生物活动热点的动态过程。对分解微生物群落的长期（超过几个月）影响描述得很差，通常无法将微生物群落与生物地球化学联系起来，这限制了我们对分解者群落及其功能的理解。我们进行了单独的为期一年的人类分解试验，一个从春季开始，另一个从冬季开始，将细菌和真菌群落结构和丰度与土壤物理化学和生物地球化学相结合，以确定微生物群落变化的关键驱动因素。在这两个试验中，土壤酸化、微生物呼吸作用升高和土壤氧气浓度降低都发生了。土壤氧气浓度的变化是微生物演替和氮转化模式的主要驱动因素，而真菌群落多样性和丰度与土壤 pH 值有关。在土壤氧气减少的时期，兼性厌氧分类群（Firmicutes 和 Saccharomycetes）的相对丰度增加。与冬季相比，春季试验的分解反应幅度和时间更大，即使校正了热量输入（累积度日数）也是如此。此外，土壤化学参数、微生物群落结构和真菌基因丰度在 1 年末仍发生改变，这表明土壤生态系统的长期影响超出了分解产物的初始脉冲。
