Division of Plant and Soil Sciences, West Virginia University, Morgantown, WV 26505, USA.
Division of Plant and Soil Sciences, West Virginia University, Morgantown, WV 26505, USA; Institute of Water Security and Science, West Virginia University, Morgantown, WV 26505, USA.
Sci Total Environ. 2021 May 1;767:145440. doi: 10.1016/j.scitotenv.2021.145440. Epub 2021 Jan 28.
Urbanization and agricultural intensification can transform landscapes. Changes in land-use can lead to increases in storm runoff and nutrient loadings which can impair the health and function of stream ecosystems. Microorganisms are an integral component of stream ecosystems. Due to the sensitivity of microorganisms to perturbations, changes in hydrology and water chemistry may alter microbial activity and structure. These shifts in microbial community dynamics may alter stream metabolism and water quality, potentially impacting higher trophic levels. Here we examine the effects of land-use and associated changes in water chemistry on sediment microbial communities by studying the West Run Watershed (WRW) a mixed-land-use system in West Virginia, USA. Streams were sampled throughout the growing season at six sites within the WRW spanning different levels of land use intensification. The proportion of land impacted by agricultural and urban development was positively correlated with temporal variation in stream sediment microbial community composition (adj R = 0.65), suggesting development can destabilize microbial communities. Moreover, streams in developed watersheds had an increased metabolic quotient (20-50% higher), this indicates that microorganisms have greater respiration per unit biomass and signifies reduced metabolic efficiency. Further, our results suggest that land use associated changes in water chemistry alter microbial function both directly and indirectly via changes in microbial community composition and biomass. Taken together our results suggest that highly developed watersheds with elevated conductivity, metal ion concentration, and pH impose stress on microbial communities resulting in reduced microbial efficiency and elevated respiration.
城市化和农业集约化会改变景观。土地利用的变化会导致暴洪径流量和养分负荷增加，从而损害溪流生态系统的健康和功能。微生物是溪流生态系统的一个组成部分。由于微生物对干扰很敏感，水文学和水化学的变化可能会改变微生物的活性和结构。这些微生物群落动态的变化可能会改变溪流的代谢和水质，从而对更高的营养级产生影响。在这里，我们通过研究美国西弗吉尼亚州的混合土地利用系统西伦流域（WRW），来检验土地利用和相关的水化学变化对沉积物微生物群落的影响。在 WRW 内的六个地点，在整个生长季节对溪流进行了采样，这些地点跨越了不同的土地利用集约化程度。受农业和城市发展影响的土地比例与溪流沉积物微生物群落组成的时间变化呈正相关（调整后的 R ² = 0.65），这表明发展可以使微生物群落不稳定。此外，在发达流域的溪流中，代谢商增加（高 20-50%），这表明微生物每单位生物量的呼吸作用更大，表明代谢效率降低。此外，我们的研究结果表明，与土地利用相关的水化学变化通过改变微生物群落组成和生物量，直接和间接改变微生物功能。总的来说，我们的研究结果表明，具有较高电导率、金属离子浓度和 pH 值的高度发达流域会对微生物群落造成压力，导致微生物效率降低和呼吸作用增加。
