摘要
Soil redox is a critical environmental factor shaping the microbial community structure and ultimately alters the nutrient cycling. However, the response of soil microbial community structure to prolonged or repeated redox fluctuations is not yet clear. To study the dynamic effects of prolonged redox disturbances to the soil microbial community structure, soil samples experiencing 8, 5 and 0 alternating oxic-anoxic cycles within approximately 6 months each year were collected and the microbial community structure were evaluated using phospholipid fatty acid analysis (PLFA) profiles. Prolonged redox disturbances had significant effects on soil physiochemical properties and soil microbial community structure. The relative abundance of straight chain saturated PLFAs, cyclopropyl, and terminal- and mid-branched chain saturated PLFAs increased due to prolonged redox disturbances, but there was a consistent decrease in linear monounsaturated PLFAs and polyunsaturated PLFAs in the fluctuating zone. Prolonged redox disturbances had a negative impact on the total PLFA content (a proxy for biomass). Both the fluctuating zone (8-cycle and 5-cycle plots) and the never flooded zone (0-cycle plots) were dominated by Gram-positive bacteria and a low content of fungi, actinomycetes and protozoa. The fungi and protozoa abundance decreased significantly with an increase in the occurrence of alternating flooding-dry events, suggesting that the prolonged redox disturbance leads to high stress on the fungi and protozoa populations. Moreover, total organic matter (TOC) and C:N ratio, environmental factors that can be influenced by recurring redox fluctuations, also influenced the microbial community structure.
摘要译文
土壤氧化还原是决定微生物群落结构并最终改变养分循环的关键环境因素。但是，土壤微生物群落结构对长时间或反复氧化还原波动的反应尚不清楚。为了研究长时间的氧化还原扰动对土壤微生物群落结构的动态影响，收集了每年约6个月内经历8、5和0交替的氧-缺氧循环的土壤样品，并通过磷脂脂肪酸分析评估了微生物群落结构（ PLFA）的个人资料。长时间的氧化还原扰动对土壤理化性质和土壤微生物群落结构有重要影响。直链饱和PLFA，环丙基以及末端和中支链饱和PLFA的相对丰度由于长时间的氧化还原扰动而增加，但在波动区内线性单不饱和PLFA和多不饱和PLFA一直减少。长时间的氧化还原干扰对总PLFA含量（生物量的替代物）具有负面影响。波动区（8个周期和5个周期的地块）和永不淹没区（0个周期的地块）均以革兰氏阳性菌和低含量的真菌，放线菌和原生动物为主。随着交替水浸-干燥事件的发生，真菌和原生动物的丰度显着下降，这表明长时间的氧化还原干扰导致真菌和原生动物种群承受高压力。此外，总有机质（TOC）和碳氮比（C：N）是可以受反复氧化还原波动影响的环境因素，也影响了微生物群落结构。
Shuling Wang[1];Sarwee J. Faeflen[1];Alan L. Wright[2];Xia Zhu-Barker[3];Xianjun Jiang[1]. Redox-driven shifts in soil microbial community structure in the drawdown zone after construction of the Three Gorges Dam[J]. Soil Ecology Letters, 2019,1(3-4): 114-125