"Especially small streams, which in this study accounted for only about four percent of the investigated water systems, turned out to be particularly important by releasing about ten times as much carbon as lakes," says Erik Lundin. "The reason for this is that streams generally have high concentrations of carbon dioxide, but also because they are turbulent which promotes exchange of gases with the atmosphere."
One of the greatest challenges of our time is to understand the effects of future climate change and its underlying causes. This requires more knowledge of the global carbon cycle, but also how it is affected by a changing climate.
Erik Lundin shows in his study that lakes release a large portion of their carbon dioxide and methane in connection with thaw. It is partly because organic materials that decompose in the lakes in the winter form dissolved carbon dioxide and methane which is then trapped under the ice. When the ice breaks up in the spring these dissolved gases are released, sometimes as quickly as within a few days.
The study also shows that two thirds of catchment carbon loss is through lakes and streams, either through emissions into the atmosphere, but also as dissolved organic and inorganic carbon, which are transported by rivers downstream.
...The results shows that Arctic lakes are more efficient carbon sequestrators than warmer boreal lakes. It indicates that with a warmer climate northern lakes will reduce their coal storage ability and we can expect larger emissions of carbon dioxide and methane from our northernmost lakes....
A lake in the Abisko region of Sweden, shot by Robin van Mourik, Wikimedia Commons via Flickr, under the Creative Commons Attribution-Share Alike 2.0 Generic license
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