Sediment bacterial community structure and function in response to C and Zn amendments: urban and nonurban streams

Abstract

AbstractUrbanization is an important ecological modifier of stream catchments and significantly alters C type and concentration and heavy metal input to aquatic systems. C and heavy metals are important determinants of microbial community structure (population dynamics) and function (physiological processes). Understanding how changes at the landscape scale affect key nutrient-transformation processes (e.g., denitrification) and C metabolism (e.g., methanogenesis) at the micro scale requires simultaneous determination of the structural and functional responses of bacterial communities. We compared total bacterial (16S ribosomal ribonucleic acid [rRNA] gene) and denitrifying bacterial (nosZ gene) community structures in sediments taken from an urban and a nonurban stream before and after C and Zn additions. Microcosms containing stream sediment were supplemented with either proteinaceous or leaf-leachate C, increasing the C content by ∼36 and 130 mg/L, respectively. C was added in the presence and absence ...