Denitrification in a large river: consideration of geomorphic controls on microbial activity and community structure

摘要: Ecological theory argues that the controls over ecosystem processes are structured hierarchically, with broader-scale drivers acting as constraints interactions and dynamics at nested levels of organization. In river ecosystems, these may arise from broadscale variation in channel form directly shapes benthic habitat structure indirectly constrains resource supply biological activity within individual reaches. To evaluate interactions, we identified sediment characteristics, water chemistry, denitrifier community factors influencing denitrification rates a sixth-order flows through two physiographic provinces transitional zone between them, each distinct geomorphological properties. We found tracked spatial changes characteristics varied seasonally expected trends stream primary production. Highest were observed during spring summer seasons province dominated by fine-grained sediments, illustrating how large-scale can constrain location hotspots. addition, nirS nirK responded differently to form, possibly due dissolved oxygen organic matter supply. This shift coincident higher N removal via suggests microbial influence biogeochemical processes.