Biogeochemical controls on streamwater and soil solution chemistry in a High Arctic environment

Abstract

A combined investigation of soil and streamwater chemistry was carried in Dicksonland (Svalbard) with the aim of identifying the key biogeochemical controls on element cycling in this young recently glaciated environment in the High Arctic. The study comprises three parts: (1) a large-scale investigation of spatial variability in streamwater chemistry; (2) an assessment of streamwater, soil and soil solution chemistry along an altitudinal transect; and (3) a study of temporal changes in soil solution and streamwater chemistry at a near-coastal site. The geochemistry of streamwaters in the study region was dominated by carbonate dissolution resulting in surface waters characterized by high pH, Ca and bicarbonate. Strong spatial variability was observed in a number of components including SO 4 2−, Na +, NH 4 + and total Al. The presence of dissolved Si in streamwaters suggests that silicate weathering is taking place. Changes in soil chemistry with increased depth were inconsistent, resulting from poor soil development partly associated with physical disturbance; this was also reflected in a poor link between soil chemical characteristics and soil solution chemistry. Internal soil processes dominated soil solution chemistry, with relatively little impact from atmospheric deposition. These processes became more important during the Arctic summer, resulting in an increase in solute concentrations in soil solutions and streamwaters.