No abstract

The paper presents the results of bathymetric mapping of selected tidewater glaciers in the St. Jonsfjorden (Svalbard) between 2004 and 2007. We also used the bathymetric data collected by the Norwegian Hydrographic Service (NHS) as well as the shaded relief images based on them. The most clearly visible traces in submarine marginal zones of the glaciers come from the Little Ice Age (LIA), i.e. the cooling period which in the area of St. Jonsfjorden might have ended no later than about 1900. At the beginning of the 20th century, i.e. during a warm period, the glaciers of St. Jonsfjorden reached their maximums. The youngest traces in the seafloor of the fjord and the bays date from this period, similar to the case of the land marginal zones. In front of the cliff of the Dahl Glacier there is a clearly visible zone of submarine moraines. It finishes exactly along the line of the LIA maximum. The sea-floor relief of the fjord and bays shows traces which we interpret as having been formed during the Late Weichselian (13-10 ka B.P.). At that time, the Dahl Glacier advanced onto the northern part of Hermansenøya; its main stream passed to the north of the island. Simultaneously, the Konow-Osborne Glacier terminated 2 to 4 km from the fjord mouth, leaving about 15 km2 of the fjord ice-free.

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The paper presents the results of hydrogeochemical and biogeochemical studies in the area of Kaffiøyra river catchments in the ablation season 2004. Vegetation, hydrological regime, mineralization and ionic composition of circulating waters, rate of annual chemical denudation and biogenic CO 2 content in soil air in relation to the concentration of dissolved and transported HCO 3 -ions were documented. The waters represented the type HCO 3 --SO 4 2--Ca. Most of ions showed a good correlation with electrical conductivity. A good correlation between dissolved and transported mass and the discharge was shown. The value of the chemical denudation in non-glacierized catchments of the Kaffiøyra plain was 0.07 and 0.13 t km -2 d -1 , in glacierized catchment -0,21 t km -2 d -1. The biogenic CO 2 concentrations in tundra soil air ranged from 0.03-0.08%, while the average was 0.046%. The mean rate of CO 2 ionic transport was 3 kg d -1 , while of HCO 3 --0.63 t d -1. A low correlation between the concentration of biogenic CO 2 in soil air and HCO 3 -was found, which indicates the involvement of other, unexamined bio-and physico-chemical processes.