Diatoms hold climate change record
13 Nov 2009 by Evoluted New Media
Diatoms – microalgae with glass-like skeletons or shells – have been used by a group of Swedish researchers to study climate change.
Diatoms – microalgae with glass-like skeletons or shells – have been used by a group of Swedish researchers to study climate change.
The team found that around 500 years ago there was a change in atmosphere circulation over Scandinavia which probably led to increased amounts of winter precipitation in Sweden.
Using diatoms in sediment from Swedish mountain lakes, Christina Jonsson, of the Department of Physical Geography and Quaternary Geology at Stockholm University, studied the changes in atmospheric circulation.
“Changes in precipitation influence in turn the oxygen content of lake water and are picked up by tiny diatoms living in the lakes. Shells from these algae are preserved in the sediment on the bottom of the lake and can be analysed to reveal changes in circulation and variations in climate since the latest ice age, that is, during the last 10,000 years,” said Jonsson
Knowledge of how the climate has varied in the past is necessary if we are to understand the causes and mechanisms behind today's climate changes and the impact of human activities on them. Northern Sweden is sensitive to changes in atmospheric circulation since the region is affected by air masses of differing origin, from the North Atlantic, the Baltic, and the Arctic. Depending on which air mass dominates, the temperature and the amount of precipitation changes. The composition of the various oxygen isotopes in precipitation is also impacted.
The study used diatoms to uncover both long-term changes in circulation and shorter periods of altered circulation patterns – and went some way to understanding a particular period in Scandinavian history.
“This change in circulation probably marks the beginning of the so-called little ice age in this region,” said Jonsson.
