Controls on stream hydrochemistry dynamics in a high Arctic snow-covered watershed

Abstract

Arctic streams are highly sensitive to climate change due to warmer air temperature and increased precipitation associated with an encroaching low Arctic climatic zone into currently high-Arctic coastal areas. Increases in nivation processes and permafrost degradation will lead to potential changes in stream physicochemical habitat, although these impacts are poorly understood. To address this gap, physicochemical habitat characteristics in streams around Zackenberg in Northeast Greenland National Park were investigated during the summers of 2013 to 2016. Streams with different sized snowpacks represented both low and high snowfall conditions leading to different nivation processes. Streams with larger snowpacks displayed lower channel stability, with higher channel mobility, suspended sediment and solute concentrations. Suspended sediment concentration was identified as a key driver of stream solute concentrations, and varying snowpack levels caused high interannual variability in solute concentrations. Winter snowpack size was confirmed to be an important driver of stream physicochemical habitat in an Arctic region with low glacial cover. We predict climate change will strongly impact stream hydrochemistry in this region through increased nivation processes alongside active layer thickening and solifluction, thereby increasing stream suspended sediment and solute concentrations. These findings indicate that hydrochemistry was principally a function of erosion, with variation being determined by spatial and temporal patterns in erosional processes, and as such, alternative methods to fingerprint water sources should be considered in this region.