Sutton Susan D, Findlay Robert H
Department of Microbiology, Miami University, Oxford, Ohio 45056, USA.
Environ Microbiol. 2003 Apr;5(4):256-66. doi: 10.1046/j.1462-2920.2003.00396.x.
A field study was conducted in the Lower East Fork of the Little Miami River, a regulated stream in Clermont county, Ohio, to determine how changes in streamflow, water temperature and photo-period affect sediment microbial community structure. Surface sediment cores were collected from sampling stations spanning 60 river kilometers three to four times per year between October 1996 and October 1999. During the final year of the field study, water temperature, water depth, conductivity, total suspended solids, dissolved organic carbon, instantaneous streamflow velocity, sediment grain size and sediment organic matter were determined. Total microbial biomass was measured using the phospholipid phosphate technique (PLP) and ranged between 2 and 134 nmol PLP * g(-1) dry weight sediment with a mean of 25 nmol PLP * g(-1). Microbial community structure was determined using the phospholipid fatty acid analysis and indicated seasonal shifts in sedimentary microbial community composition. January to June sedimentary microbial biomass was predominately prokaryotic (60% +/- 2), whereas microeukaryotes dominated samples collected during the late summer (55% +/- 2.4) and fall (60% +/- 2). These changes were correlated with stream discharge and water temperature. Microbial community structure varied spatially about a reservoir with prokaryotic biomass dominant at upstream stations and eukaryotic biomass dominant at downstream stations. These findings reveal that sedimentary microbial communities in streams are dynamic responding to the seasonal variation of environmental factors.
在俄亥俄州克莱蒙特县一条受调控的河流——小迈阿密河的下东支流开展了一项实地研究，以确定流量、水温及光周期的变化如何影响沉积物微生物群落结构。1996年10月至1999年10月期间，每年三到四次从跨越60公里河流的采样站采集表层沉积物岩心。在实地研究的最后一年，测定了水温、水深、电导率、总悬浮固体、溶解有机碳、瞬时水流速度、沉积物粒度和沉积物有机质。使用磷脂磷酸盐技术（PLP）测量总微生物生物量，范围在2至134 nmol PLP * g(-1)干重沉积物之间，平均值为25 nmol PLP * g(-1)。使用磷脂脂肪酸分析确定微生物群落结构，结果表明沉积微生物群落组成存在季节性变化。1月至6月沉积微生物生物量主要为原核生物（60% +/- 2），而微型真核生物在夏末（55% +/- 2.4）和秋季（60% +/- 2）采集的样本中占主导地位。这些变化与河流流量和水温相关。微生物群落结构在水库周围存在空间差异，上游站点原核生物生物量占主导，下游站点真核生物生物量占主导。这些发现表明，河流中的沉积微生物群落是动态的，对环境因素的季节性变化做出响应。
