Changes in water chemistry along the newly formed High Arctic fluvial–lacustrine system of the Brattegg Valley (SW Spitsbergen, Svalbard)

Changes in water chemistry along the High Arctic fluvial–lacustrine system located in Wedel Jarlsberg Land in the SW Spitsbergen (Svalbard) were investigated during the summer season of 2010 and 2011. The newly formed river–lake system consists of three lakes connected with the Brattegg River. The first bathymetric measurements of these lakes were made by the authors in 2010. The Brattegg River catchment represents a partly glaciered Arctic water system. The studied lakes are characterized by low mineralization and temperature of water. The value of the electrolytic conductivity (EC) ranges from 30.2 to 50.5 μS cm−1 and the temperature of surface water from 1.5 to 7.8 °C. The temperature increase takes place downstream starting from Upper Lake to the outflow from Myrktjorna Lake. The waters of lakes have higher temperatures than the stream. The predominant ions are HCO3 − (up to 16.5 mg L−1), Cl− (6.66–8.53 mg L−1), Ca2+ (2.40–4.45 mg L−1) and Na+ (2.65–3.36 mg L−1). The highest values of ammonium and DOC found in the lowest Myrktjorna Lake seem to be related to the presence of aquatic organisms and also birds. From the group of 10 analyzed microelements, increased concentrations of aluminum, up to almost 500 μg L−1, are present in the lakes’ water. Water isotopic composition ranges for δ18O and δ2H, from −10.6 to −10.9‰ and from −70.8 to −72.3‰, respectively. The vertical zonality of lake waters is manifested in a decrease in the temperature and increase in EC and chemical elements concentrations.