The vast subarctic region extends across permafrost soils from the northern treeline to arctic tundra, and is a landscape rich in lakes, ponds, wetlands, streams and rivers. One of the major classes of freshwater ecosystems is thaw lakes, also called thermokarst lakes. These form as melted basins in the permafrost that fill with water. Fish are generally absent but they are often contain abundant populations of zooplankton. These waters appear to be major sources of greenhouse gases, and there is therefore considerable interest in their limnological properties and the microbial communities that are responsible for their CH4 and CO2 dynamics.
Thaw lakes in the North of Quebec, Canada (From Isabelle Laurion, INRS-ETE, QC).
Pingualuit Crater Lake, Quebec, Canada. (From this website)
The subarctic also contains many large lakes, mostly formed by glacial activity. Several crater lakes are also known throughout this region, formed by meteoritic impacts. These include Lac à l’Eau Claire (Clearwater Lake) and Pingualuit Crater Lake, both in Northern Québec. The latter is known by the Inuit as “The Crystal Eye” because of its legendary clarity, and it may have persisted as a liquid water microbial ecosystem beneath the thick ice cover during past glacial cycles.
