Characterising geogenic nitrate source areas in Adventdalen

There has been great emphasis on quantifying the release of greenhouse gases such as carbon dioxide and methane from melting permafrost. However, research on links between melting glaciers and permafrost and nitrogen release has been limited, despite its potential as a direct or indirect greenhouse gas. Recent studies have suggested that weathering of shale and coal bedrock in proglacial/periglacial environments has the potential to be a terrestrial hotspot for nitrogen release into the aquatic system. Mobilised nitrate may be converted into nitrous oxide (a greenhouse gas ~300 times more potent than CO2 on a 100-year time scale), and may impact nitrogen-limited coastal ecosystem productivity and carbon cycling. Svalbard is one of these potential terrestrial nitrogen hotspots, and is therefore an ideal place to quantify geogenic N sources, subsequent transport and processing across the aquatic continuum, and eventual marine fate. Last year, an AFG awarded as part of the NITRIRUN project (RiS ID 12255) gathered detailed data from one small catchment near Longyearbyen, to investigate the processing and cycling of nitrogen on land in one small river system. In the proposed fieldwork, we will start upscaling this work. The ultimate aim is to develop a process-based catchment nitrogen model for Adventdalen in southwest Spitsbergen, representing geogenic N mobilisation, vertical nitrous oxide losses during transit from source area to coast, and coastal delivery. A crucial first step in setting up this model is to define the source areas of geogenic nitrogen, and that is the focus of this AFG. Project aims are therefore to establish: (1) where geogenic nitrate is entering surface waters; (2) nitrate concentrations and their variability; and (3) link results to broader landscape features that can be easily derived from readily-available spatial datasets, for upscaling and extrapolation outside the study area.