Water chemistry of tundra lakes in the periglacial zone of the Bellsund Fiord (Svalbard) in the summer of 2013

Highlights: • The study involved analysing tundra lakes in the Bellsund region. • Non-sea-salt SO₄^{2 −} and Mn, Co, Ni, Cu, Ga, Ba and Cd in tundra lakes are of atmospheric origin. • Cl⁻ content in tundra lakes shows marine aerosol influence. • NO₃⁻ present in tundra lakes may be a consequence of biological processes and permafrost thawing. Climate changes observed in the Arctic (e.g. permafrost degradation, glacier retreat) may have significant influence on sensitive polar wetlands. The main objectives of this paper are defining chemical features of water within six small arctic lakes located in Bellsund (Svalbard) in the area of continuous permafrost occurrence. The unique environmental conditions of the study area offer an opportunity to observe phenomena influencing water chemistry, such as: chemical weathering, permafrost thawing, marine aerosols, atmospheric deposition and biological inputs. In the water samples collected during the summer 2013, detailed tundra lake water chemistry characteristics regarding ions, trace elements, pH and specific electrolytic conductivity (SEC₂₅) analysis were determined. Moreover, water chemistry of the studied lakes was compared to the water samples from the Tyvjobekken Creek and precipitation water samples. As a final step of data analysis, Principal Component Analysis (PCA) was performed. Detailed chemical analysis allowed us to conclude what follows: (1) Ca^{2 +}, Mg^{2 +}, SO₄^{2 −}, Sr are of geogenic origin, (2) NO₃⁻ present in tundra lakes and the Tyvjobekken Creek water samples (ranging from 0.31 to 1.69 mg L⁻¹ and from 0.25 to 1.58 mg L⁻¹ respectively) may be of mixed origin, i.e. from biological processes and permafrost thawing, (3) high contribution of non-sea-salt SO₄^{2 −} > 80% in majority of studied samples indicate considerable inflow of sulphate-rich air to the study area, (4) high content of chlorides in tundra lakes (range: 25.6–32.0% meq L⁻¹) indicates marine aerosol influence, (5) PCA result shows that atmospheric transport may constitute a source of Mn, Co, Ni, Cu, Ga, Ba and Cd. However, further detailed inter-season and multi-seasonal study of tundra lakes in the Arctic are recommended. Especially in terms of detailed differentiation of sources influence (atmospheric transport vs. permafrost degradation).