Department of Biology, Loyola University Chicago, Chicago, Illinois, USA.
Appl Environ Microbiol. 2013 Mar;79(6):1897-905. doi: 10.1128/AEM.03527-12. Epub 2013 Jan 11.
In highly urbanized areas, wastewater treatment plant (WWTP) effluent can represent a significant component of freshwater ecosystems. As it is impossible for the composition of WWTP effluent to match the composition of the receiving system, the potential exists for effluent to significantly impact the chemical and biological characteristics of the receiving ecosystem. We assessed the impacts of WWTP effluent on the size, activity, and composition of benthic microbial communities by comparing two distinct field sites in the Chicago metropolitan region: a highly urbanized river receiving effluent from a large WWTP and a suburban river receiving effluent from a much smaller WWTP. At sites upstream of effluent input, the urban and suburban rivers differed significantly in chemical characteristics and in the composition of their sediment bacterial communities. Although effluent resulted in significant increases in inorganic nutrients in both rivers, surprisingly, it also resulted in significant decreases in the population size and diversity of sediment bacterial communities. Tag pyrosequencing of bacterial 16S rRNA genes revealed significant effects of effluent on sediment bacterial community composition in both rivers, including decreases in abundances of Deltaproteobacteria, Desulfococcus, Dechloromonas, and Chloroflexi sequences and increases in abundances of Nitrospirae and Sphingobacteriales sequences. The overall effect of the WWTP inputs was that the two rivers, which were distinct in chemical and biological properties upstream of the WWTPs, were almost indistinguishable downstream. These results suggest that WWTP effluent has the potential to reduce the natural variability that exists among river ecosystems and indicate that WWTP effluent may contribute to biotic homogenization.
在高度城市化地区，污水处理厂（WWTP）的出水可能是淡水生态系统的重要组成部分。由于 WWTP 出水的成分不可能与接收系统的成分相匹配，因此出水有可能对接收生态系统的化学和生物特性产生重大影响。我们通过比较芝加哥大都市区的两个截然不同的野外地点来评估 WWTP 出水对底栖微生物群落的大小、活性和组成的影响：一个是高度城市化的河流，接收来自大型 WWTP 的废水，另一个是接收来自小型 WWTP 的废水的郊区河流。在远离废水输入的上游地点，城市和郊区河流在化学特征和沉积物细菌群落组成上存在显著差异。尽管废水中的无机养分含量显著增加，但令人惊讶的是，它也导致沉积物细菌群落的种群大小和多样性显著下降。细菌 16S rRNA 基因的标签焦磷酸测序显示，废水中含有显著的效应，对两条河流的沉积物细菌群落组成有显著影响，包括减少了 Delta 变形菌、脱硫球菌、脱氯单胞菌和绿弯菌序列的丰度，增加了硝化螺旋菌和鞘脂杆菌序列的丰度。WWTP 输入的总体影响是，这两条河流在 WWTP 上游的化学和生物特性上存在明显差异，但在 WWTP 下游几乎无法区分。这些结果表明，WWTP 废水有可能降低河流生态系统之间存在的自然变异性，并表明 WWTP 废水可能导致生物同质化。
