Microorganisms in the Ground Don’t Slack Off in Winter

ScienceDaily (Nov. 16, 2010) — It is known that soil microorganisms can maintain some activity during the cold winter months. Scientist at Swedish University of Agricultural Sciences (SLU) and Umeå University in Sweden have now shown that the microorganisms in frozen soils are much more viable than previously anticipated and also has large potential for growth.

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In northern forest ecosystems, there is a great deal of carbon stored in the ground. The degradation of this carbon supply is a crucial component in computational models used to describe the effects of future climate changes.

In recent years it has been noticed that the winter half of the year can also have a great impact on the carbon balance of forests, as microorganisms (fungi and bacteria) continue to degrade organic carbon despite freezing temperatures and frozen ground. Just how microorganisms go about breaking down organic carbon under such adverse conditions has largely been unknown, which has rendered it difficult to carry out reliable calculations of a forest's carbon balance in wintertime.

"The results of previous studies have been interpreted as meaning that microorganisms in frozen ground cannot grow but merely give off a certain amount of carbon dioxide. A research team at SLU in Umeå and at Umeå University has now shown that this is not the case. Instead, the capacity of microorganisms to grow in frozen ground is astonishingly similar to that of the summer half of the year, although the growth rate is lower," says Mats Öquist from SLU, who directed the study.

These findings are being published this week in the journal PNAS, published by the American Academy of Sciences.

Article continues: http://www.sciencedaily.com/releases/2010/11/101116093827.htm