Spatial variations in activity and composition of the Chicago River System microbiome. freshwater sediment metagenome

Freshwater ecosystems in urban habitats are vulnerable to human activity. Microbial communities are essential to nutrient cycling within these habitats, so there is interest in understanding how anthropogenic stressors may impact them. We conducted our study in the Chicago River system, which receives multiple sources of anthropogenic inputs including effluent from a large wastewater treatment plant. The goal of this project was to characterize the activity, abundance, and taxonomic composition of benthic bacterial communities in the Chicago River system, and to determine how these parameters varied across locations within the system. Specifically, we measured nutrient chemistry, bacterial community activity (respiration and denitrification), bacterial abundance (direct counts), and bacterial community composition (next-generation sequencing of 16S rRNA genes) at nine sites within the North Shore Channel, North Branch and Main Stem of the Chicago River. We found significant variations in nutrient chemistry and bacterial community activity, abundance and composition, and observed a significant effect of the wastewater treatment plant effluent. The results of this study provide valuable insight into the influence of anthropogenic stressors on the microbiome of an urban river.