The Arctic contains a variety of types of lakes but overall, it is thermokarst lakes and ponds that are the most abundant and productive aquatic ecosystems in the Arctic. They are found extensively in the lowland regions of western and northern Alaska, Canada and Siberia. These (i.e., thaw) lakes are most commonly formed by the thaw of ice-rich permafrost, which leads to the collapse of ground levels and ponding of surface water in the depression. Continued thawing of the permafrost can lead to the drainage and eventual disappearance of these lakes, as can erosion and lake coalescence. As illustrated in this figure - net increases in lake abundance and area have occurred in continuous permafrost, suggesting an initial but transitory increase in surface ponding.
From collection: Arctic Biodiversity Trends 2010
Hugo Ahlenius, GRID-Arendal & CAFF