| Summary: | Measurements of CO2 concentrations in soil air were taken in the summer sea− sons of 1998 and 2001 in SW Spitsbergen. The measurements were carried out in three small non−glaciated catchments in the Hornsund region close to the Polish Polar Station. The pre− liminary measurementsw ere made using a Dräger’spump and ampulesw hich contained an alkaline absorbent (1998). Later (2001), a new more accurate apparatus which uses a gravimetric method wastes ted. A variety of different geographical situationswaschos en for the CO2 measurements. These included areas which differed in respect of the local hydrology, terrain relief, exposure to solar radiation, distance from the sea and quantity of seabird excre− ments in the soil. The measured concentrations of soil CO2 varied between 0.05 and 0.3% (with one exceptionally high value close to 0.5%). Owing to the local conditions, the differ− encesbet ween CO2 concentrations seem closely to relate to the specific properties of each catchment. Much of the biogenic CO2 present in water that circulates in tundra catchments which have a limestone foundation becomes involved in the dissolution of that limestone. In July 2001, about 40% of the CO2 was used in the dissolution of the carbonate rocks (30.3 kg/km2 month), the “free” CO2 being transported to the sea at Isbjørnhamna Bay (40.4 kg/km2 month). In contrast, the water flowing through acidic rocks are rich in “free” CO2. The concentrations of dissolved and transported HCO3 – ionsfrom the polar catchments are closely correlated with variations in the daily production of biogenic CO2.
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