1 Forest, Nature and Biomass, Department of Geosciences and Natural Resource Management, Faculty of Science, Københavns Universitet2 Geology, Department of Geosciences and Natural Resource Management, Faculty of Science, Københavns Universitet3 Institut for Geoscience4 University College5 Applied ecology, Forest & Landscape Denmark, Faculty of Life Sciences, Københavns Universitet6 Institut for Fysik og Astronomi, AU7 Applied ecology, Forest & Landscape Denmark, Faculty of Life Sciences, Københavns Universitet8 Geology, Department of Geosciences and Natural Resource Management, Faculty of Science, Københavns Universitet
Groundwater in front of warm-based glaciers is likely to become a more integrated part of the future proglacial hydrological system at high latitudes due to global warming. Here, we present the first monitoring results of shallow groundwater chemistry and geochemical fingerprinting of glacier meltwater in front of a warm-based glacier in Southeast Greenland (Mittivakkat Gletscher, 65 degrees 41 N, 37 degrees 48 W). The groundwater temperature, electrical conductivity and pressure head were monitored from August 2009 to August 2011, and water samples were collected in 2009 and analyzed for major ions and water isotopes (D, 18O). The 2yrs of monitoring revealed that major outbursts of glacier water during the ablation season flushed the proglacial aquifer and determined the groundwater quality for the next 2-8 weeks until stable chemical conditions were reached again. Water isotope composition shows that isotopic fractionation occurs in both groundwater and glacier meltwater, but fractionation due to evaporation from near-surface soil moisture prior to infiltration has the most significant effect. This study shows that groundwater in Low Arctic Greenland is likely to possess a combined geochemical and isotopic composition, which is distinguishable from other water sources in the proglacial environment. However, the shallow groundwater composition at a given time is highly dependent on major outbursts of glacier water in the previous months.
Geografiska Annaler. Series A. Physical Geography, 2013, Vol 95, Issue 2, p. 97-108