Effects of an Arctic Environment on the Origin and Development of Freshwater Lakes1
Thaw lakes beyond the glacial boundary in northern Alaska may be quiescent, with elliptical saucer‐shaped basins, or they may be actively expanding, with deeply pocked basins. Glacial lakes of the usual types are found in the glaciated southern part of the region. The lakes freeze to a depth of almo...
| Published in: | Limnology and Oceanography |
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| Main Authors: | , , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Wiley
1958
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| Subjects: | |
| Online Access: | http://dx.doi.org/10.4319/lo.1958.3.2.0192 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.4319%2Flo.1958.3.2.0192 https://aslopubs.onlinelibrary.wiley.com/doi/pdf/10.4319/lo.1958.3.2.0192 |
| Summary: | Thaw lakes beyond the glacial boundary in northern Alaska may be quiescent, with elliptical saucer‐shaped basins, or they may be actively expanding, with deeply pocked basins. Glacial lakes of the usual types are found in the glaciated southern part of the region. The lakes freeze to a depth of almost 2 meters in winter and warm without stratifying to about 13°C in summer. Of the annual heat budget of some 28,000 cal/cm 2 only 6,000 cal is wind distributed. Total dissolved solids are known to range from 35 to 159 ppm, and the water is of a calcium bicarbonate type except where sea‐spray influence is strong. The silica content is very low. A shore community is poorly‐developed or absent, apparently because of ice‐push, and the standing crop of benthos varies from an indetectable amount to 89.4 kg/ha. Remains of the midge Dryadotanytarsus are found throughout the sedimentary column of one lake, indicating that this genus, which is known only as a late‐Pleistocene fossil, lives there today. The sediments of lakes receiving the products of the widespread processes of arctic weathering are very inorganic, with few and poorly‐preserved microfossils. Computations based on a radiocarbon‐dated pollen chronology suggest a net community productivity averaging less than 2 mg of organic matter/cm 2 /yr, and Bosmina and tendipedid productivities of less than 10/cm 2 /yr during the past 6,000 years. Further computations involving the data of other authors suggest that of the solar energy fixed by a temperate or arctic lake about one‐quarter is preserved in the sediments, one‐half is dissipated by the decomposing organisms and one‐quarter is dissipated by all the other plants and animals. The arctic environment appears to influence lakes principally through physiographic processes affecting origin, sedimentation, and drainage. |
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