Effects of urbanization on sediment microbial communities in lotic ecosystems.

摘要

The world is becoming increasingly urbanized, with the majority of the world's population now living in urban areas. Urbanization has the potential to significantly alter lotic ecosystems and the services they provide. Benthic microbial communities are key components of lotic ecosystems due to their contributions to primary production and nutrient cycling. Two types of human inputs associated with urbanization that may impact benthic microbial communities in lotic ecosystems are the input of wastewater treatment effluent and the input of emerging contaminants, including pharmaceuticals and personal care products. This work examines the effects of treated WWTP effluent on benthic microbial communities obtained from a field study of two streams in the Chicago metropolitan area. In addition, the presence and effects of a widely used antimicrobial, triclosan, was studied both in the field and using the artificial stream facility located at Loyola University Chicago.;Our findings suggest that WWTP effluent significantly reduce both chemical and biological variation in the benthic ecosystems. These results raise questions about the impacts of anthropogenic ecosystem modifications and WWTPs on lotic ecosystems. Results also indicated that WWTPs were not significant point sources of triclosan, suggesting that non-point sources are more significant sources of triclosan into lotic ecosystems. However, sediment triclosan concentrations correlated closely with the degree of urbanization of the surrounding habitat. Using model streams we were able to generate a triclosan resistant bacterial community that was similar in size to control streams from a single dosing of triclosan.