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Abstract

Abstract During July 1975 limnological investigations were carried out in 35 selected standing waters distributed all over Bear Island (74°30'N, 19°E). In standing waters ranging from temporary ponds to deep lakes, temperatures were foundbetween 2.5 and 12.5°C, pH-values between 5.1-6.7, values of electric conductivity between 50 and 253 µmho, chlorides between 0.41 and 2.05 meqv/l, and alkalinity between 0.44 and 2.30 meqv/l. Differences in conductivity and chloride content were caused by spray from the sea, differences in alkalinity by the subsoil and in addition by the bathing activity of seabirds, which also raised the hydrogen ion concentration (pH). With the exception of some waters in the hilly part which were cooler, temperatures in the water were higher than air temperatures, especially during periods of sunshine. Daphnia pulex was limited to ponds and shallow lakes; in the latter it can sometimes winter under the ice. Benthic Cladocera species like Macrothrix hirsuticornis and Chydorus sphaericus were found additionally in temporary ponds and deep lakes. There was no indication that Cladocerans are limited by chemical factors.