Climate change is reshaping the face of Arctic landscapes, including patterns of terrestrial productivity, soil processes, and hydrologic fluxes. Such changes have broad consequences for the supply of carbon and nutrients across land-water boundaries. At the same time, the capacity for streams and rivers to respond to these supplies may alter the downstream fate of these elements in the Arctic landscape. Here we synthesize research from the Miellajokka Catchment in northern Sweden to explore the contraints on stream ecosystem metabolism and assess how its variation may influence carbon and nitrogen cycling at multiple spatial and temporal scales. Continuous estimates of gross primary production (GPP) and ecosystem respiration (ER) across this drainage network reveal a diversity of seasonal patterns, which reflect the joint influences of physical constraints and nutrient limitation on rates of stream biological activity. At diel time scales, GPP can in turn create significant biogeochemical signals that are meaningful to broader-scale flux estimates. At seasonal scales, variation in the development of metabolic capacity in streams further governs the extent to which biological processes can influence carbon and nitrogen fluxes downstream. Finally, at interannual scales, differences in the timing and character of spring snowmelt can influence rates of metabolic activity and biogeochemical fluxes throughout the open water season. Collectively, our observations highlight the potential for stream ecosystem processes to influence biogeochemical cycles in a changing Arctic.

Primary Presenter: Ryan Sponseller, Umea University (ryan.sponseller@umu.se)

Authors:

Gerard Rocher-Ros, Swedish University of Agricultural Sciences  (gerard.rocher.ros@slu.se)

Maria Myrstener, Swedish University of Agricultural Sciences  (maria.myrstener@slu.se)

Chelsea Hintz, University of Cincinnati  (hintzca@mail.uc.edu)

Ishi Buffam, Swedish University of Agricultural Sciences  (ishi.buffam@slu.se)

Reiner Giesler, Umea University  (reiner.giesler@umu.se)