Permafrost ponds as conduits for carbon

Posted on September 22, 2010

At arctic and sub-arctic latitudes, the most common aquatic systems are those created by the thawing of permafrost, which covers about a quarter of the land surface in the northern hemisphere.  Although permafrost thawing is expected to accelerate in response to increasing atmospheric temperatures, few studies have described thaw ponds and their potential role in global climate change.  A survey of Canadian permafrost ponds revealed high concentrations of nutrients, dissolved organic matter and bacteria, and productivity levels that were similar to those of temperate lakes.  Concentrations of CO2  increased with depth, which suggested that most CO2  was produced by respiration at the pond bottom.   While variations in thaw pond conditions made it hard to generalize about their role in greenhouse gas production, it was noteworthy that most study ponds were supersaturated in methane and carbon dioxide.  There is a need to extend this work with measurements of gas fluxes in permafrost ponds and better estimates of the total area of these water bodies.

Reference:  Breton, J., Vallieres, C. & Laurion, I.  2009.  Limnological properties of permafrost thaw ponds in northeastern Canada.  Canadian Journal of Fisheries & Aquatic Sciences 66, 1635–1648.