Rising temperatures are bringing the world’s northernmost lake back to life.
In what has been described as “a pure climate change story”, Lake Kaffeklubben Sø near the cost of Greenland has become rejuvenated with microscopic algae called “diatoms”.
The lake was formed about 3,500 years ago when glacial retreats created numerous small lakes on the coastal plain, at this time diatoms were abundant. As temperatures started to cool, the population of these algae decreased until about 2,400 years ago when they vanished completely.
A layer of ice 1-2 metres thick covers the lake year round and blocks the passage of sunlight from allowing diatoms to grow.
Now, however, a rise in summer temperatures has caused some of the ice to melt, particularly on the periphery of the lake- this has allowed enough sunlight to penetrate the waters and hence since the 1980s diatom populations have been increasing.
To be confident that this population explosion could be attributed to increased temperatures, the research team allocated a large portion of the study to examine other possible scenarios. The main investigation was to determine was the surge in diatoms caused in part by nutrient enrichment; in the form of nitrogen pollution. There was no evidence of pollution, nitrogen or otherwise, found in Kaffeklubben Sø, suggesting that the current rise in diatom population is due to climate change alone.
The study noted that the current diatom population in Kaffeklubben Sø is the highest in recent memory. This goes to show how sensitive ecosystems are to a changing climate.
For those with access, the paper can be found here: http://geology.gsapubs.org/content/40/11/1003.full.pdf+html
For those who don’t, next best thing! : http://www.newscientist.com/article/dn22337-worlds-most-northerly-lake-comes-back-to-life.html
Photograph courtesy David Mazzucchi