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Microbial growth in Arctic tundra soil at -2°C
Shawna K McMahon1, Matthew D Wallenstein, Joshua P Schimel
1Natural Resource Ecology Laboratory, Colorado State University, Fort Collins, CO 80523, USA. Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, CA 93117, USA.
Environmental Microbiology Reports
|June 15, 2013
Summary
Arctic tundra microbes can grow in frozen winter soils, synthesizing new cell membranes and DNA. This finding has significant implications for carbon cycle modeling in a changing climate.
Area of Science:
- Microbial ecology
- Soil science
- Biogeochemistry
Background:
- Microbial activity in permanently frozen environments is known, but growth in seasonally frozen Arctic tundra soils is less understood.
- Respiration in frozen tundra soils suggests maintenance metabolism, not necessarily growth, which requires new cell material synthesis.
Purpose of the Study:
- To investigate microbial growth in Arctic tundra soils during winter conditions.
- To determine if microbes synthesize new cellular components (DNA, lipids) under frozen conditions.
Main Methods:
- Laboratory microcosm study using Arctic tundra soil samples.
- Traced carbon-13 glucose incorporation into membrane lipids.
- Monitored DNA synthesis using 5-bromo-3-deoxyuridine.
Main Results:
- Microbes in frozen tundra soils demonstrated synthesis of new cell membranes and DNA, indicating growth.
- Fungi showed higher carbon incorporation than other microbial groups.
- Microbial activity varied by soil type (shrub vs. tussock) and season (early vs. late winter).
Conclusions:
- Microbial growth occurs in frozen Arctic tundra soils during winter.
- This wintertime growth has potential implications for carbon cycle dynamics and climate change models.
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