Northernmost Lake Resurrected Due to Warming

By Kate Andries, National Geographic
October 17 2012
http://news.nationalgeographic.com/news/2012/10/121017-northernmost-lake-greenland-global-warming-science-environment/

Summary
The world's northernmost lake called  Kaffeklubben Sø , situated near the coast of Greenland, was once teeming with a microscopic algae called diatom, which was formed 3500  years ago due to glacial retreats which created numerous small lakes on the plain. However studies show that the population had decreased and diminished over 2400 years ago. Scientist believe that the lake was deeply frozen, cutting off any sunlight from getting on to the water and providing the algae with energy to perform photosynthesis. So the drop in temperatue and the lack of sunlight led to the organisms being killed off. This had been the case since roughly 1920. Around 1960-1970, scientists had found evidence that the diatom population had begun to gradually increase due to summer temperatures increasing as well. Climate change certainly played a role in this case. The diatom population had exploded from 1980 onwards. The layer of ice on the lake which was usually 1 to 2 meters thick had now reduced with summer temperatures rising to 1.6 degrees celsius particularly towards the shore. Scientist were determined to see if the the sudden boost of the diatom population was the result of nitrogen pollution which can cause algae to bloom but that hypothesis was refuted when they found no evidence of pollution. They confirmed that the only reason for this increase in population was because of climate change.

Connection
Connections between this article and what we have learnt so far in biology are that climate change, specifically global warming, can have a huge impact on the living apsects of our ecosystems. The photic zone in ponds and lakes are where most plants and microscopic algae such as phytoplankton and in this particular case, diatom are ideal places where photosynthesis occurs. Since the lake had frozen, the ice had blocked out all means of sunlight from getting to the diatom which killed the species in this lake due to lack of energy. Fortunately, thanks to global warming, the climate in Greenland had started to become warmer especially in the summer, melting the ice mostly towards the shore and allowing photosynthesis back in to help re-populate Kaffeklubben Sø lake with diatoms again. Although the hypothesis was not valid, it was suspected that nitrogen pollution had caused algae to bloom but it was more of a  climate- driven change than a nutrient-driven change.