BioTechnology Institute, University of Minnesota St. Paul, MN, USA.
BioTechnology Institute, University of Minnesota St. Paul, MN, USA ; Department of Biology Teaching and Learning, University of Minnesota St. Paul, MN, USA.
Front Microbiol. 2014 Oct 8;5:524. doi: 10.3389/fmicb.2014.00524. eCollection 2014.
Local and regional associations between bacterial communities and nutrient and chemical concentrations were assessed in the Upper Mississippi River in Minnesota to determine if community structure was associated with discrete types of chemical inputs associated with different land cover. Bacterial communities were characterized by Illumina sequencing of the V6 region of 16S rDNA and compared to >40 chemical and nutrient concentrations. Local bacterial community structure was shaped primarily by associations among bacterial orders. However, order abundances were correlated regionally with nutrient and chemical concentrations, and were also related to major land coverage types. Total organic carbon and total dissolved solids were among the primary abiotic factors associated with local community composition and co-varied with land cover. Escherichia coli concentration was poorly related to community composition or nutrient concentrations. Abundances of 14 bacterial orders were related to land coverage type, and seven showed significant differences in abundance (P ≤ 0.046) between forested or anthropogenically-impacted sites. This study identifies specific bacterial orders that were associated with chemicals and nutrients derived from specific land cover types and may be useful in assessing water quality. Results of this study reveal the need to investigate community dynamics at both the local and regional scales and to identify shifts in taxonomic community structure that may be useful in determining sources of pollution in the Upper Mississippi River.
本研究旨在明尼苏达州密西西比河上游地区，评估细菌群落与营养物和化学物质浓度之间的局部和区域关联，以确定群落结构是否与与不同土地覆盖相关的离散类型的化学输入有关。通过对 16S rDNA V6 区的 Illumina 测序来描述细菌群落，并将其与>40 种化学物质和营养物浓度进行比较。细菌群落的局部结构主要由细菌目之间的关联所塑造。然而，目丰度与营养物和化学物质浓度在区域上相关，并且与主要土地覆盖类型也有关。总有机碳和总溶解固体是与局部群落组成相关的主要非生物因素之一，并且与土地覆盖共变。大肠杆菌浓度与群落组成或营养物浓度的相关性较差。14 个细菌目的丰度与土地覆盖类型有关，其中 7 个在森林或人为影响的地点之间的丰度存在显著差异（P≤0.046）。本研究确定了与特定土地覆盖类型来源的化学物质和营养物相关的特定细菌目，这可能有助于评估水质。本研究的结果表明，需要在局部和区域尺度上研究群落动态，并识别分类群落结构的变化，这可能有助于确定密西西比河上游地区的污染来源。
