PULSE · Potential nUtrient release from deglaciating Land Surfaces to downstream Ecosystems (PULSE)

Glacier retreat is escalating in response to amplified Arctic warming. This exposes large areas of new glacier forefield to seasonal freeze-thaw, wetting-drying cycles and variable oxygen conditions. These physical changes dramatically alter biogeochemical cycling in previously glaciated sediments, facilitating soil and vegetation development in the 21st century. Arctic streams are well-known suppliers of the key nutrient nitrogen (N) to N-limited fjords and coasts, which host lucrative fisheries. However, the influence of glacial retreat and associated soil development on N release to streams, thus fjords and coasts, is a complete unknown. The PULSE project aims to quantify the impact of Arctic glacier forefield exposure on soil N cycling and export to coastal marine environments, and how they are influenced by time since deglaciation, local geology and freeze-thaw cycling. In PULSE, I will measure N release from a field scale chronosequence in a Sub-Arctic glaciated catchment and quantify the forefield soil N contribution to river N runoff. I further use a “space for time” approach to simulate future climate conditions for High Arctic forefield sediments, thus predicting future High Arctic forefield N release. This highly interdisciplinary project combines my background in soil biogeochemistry with glacier hydrochemistry at the Arctic University of Tromsø (UiT). UiT is the ideal host for me to gain new analytical chemistry and modelling skills in order to establish how future glacier retreat will shift sources of riverine N transport to downstream fjords and coasts. A secondment to the Norwegian Polar Institute will additionally expand my scientific expertise and network to include marine monitoring stakeholders directly using my results. PULSE will, therefore, provide a high-impact, first quantification of future potential proglacial soil N leaching across Sub-Arctic to High Arctic climates, which will inform future ecosystem management policies in the Arctic.