Size distribution
Despite the importance of thermokarst (thaw) lakes of the subarctic zone in regulating greenhouse gas exchange with the atmosphere and the flux of metal pollutants and micro-nutrients to the ocean the inventory of lake distribution and stock of solutes for the permafrost-affected zone are not availa...
| Published in: | Water |
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| Main Authors: | , , , , , , , , , , , , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
2017
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| Subjects: | |
| Online Access: | https://doi.org/10.3390/w9030228 http://vital.lib.tsu.ru/vital/access/manager/Repository/vtls:000645268 |
| Summary: | Despite the importance of thermokarst (thaw) lakes of the subarctic zone in regulating greenhouse gas exchange with the atmosphere and the flux of metal pollutants and micro-nutrients to the ocean the inventory of lake distribution and stock of solutes for the permafrost-affected zone are not available. We quantified the abundance of thermokarst lakes in the continuous discontinuous and sporadic permafrost zones of the western Siberian Lowland (WSL) using Landsat-8 scenes collected over the summers of 2013 and 2014. In a territory of 105 million ha the total number of lakes >0.5 ha is 727,700 with a total surface area of 5.97 million ha yielding an average lake coverage of 5.69% of the territory. Small lakes (0.5–1.0 ha) constitute about one third of the total number of lakes in the permafrost-bearing zone of WSL yet their surface area does not exceed 2.9% of the total area of lakes in WSL. The latitudinal pattern of lake number and surface coverage follows the local topography and dominant landscape zones. The role of thermokarst lakes in dissolved organic carbon (DOC) and most trace element storage in the territory of WSL is non-negligible compared to that of rivers. The annual lake storage across the WSL of DOC Cd Pb Cr and Al constitutes 16% 34% 37% 57% and 73% respectively of their annual delivery by WSL rivers to the Arctic Ocean from the same territory. However given that the concentrations of DOC and metals in the smallest lakes (<0.5 ha) are much higher than those in the medium and large lakes the contribution of small lakes to the overall carbon and metal budget may be comparable to or greater than their contribution to the water storage. As such observations at high spatial resolution (<0.5 ha) are needed to constrain the reservoirs and the mobility of carbon and metals in aquatic systems. To upscale the DOC and metal storage in lakes of the whole subarctic the remote sensing should be coupled with hydrochemical measurements in aquatic systems of boreal plains. |
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