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Microbial life in permafrost.
E Rivkina1, K Laurinavichius, J McGrath
1Institute for Physicochemical and Biological Problems in Soil Science, Russian Academy of Sciences, Pushchino, Moscow Region, Russia. rivkina@issp.serpukhov.su
Advances in Space Research : the Official Journal of the Committee on Space Research (COSPAR)
|April 6, 2005
Summary
Methane production in Siberian permafrost significantly decreases at sub-zero temperatures. Cold-adapted microbes in permafrost are crucial for nutrient cycling and greenhouse gas regulation upon thawing.
Area of Science:
- Microbiology
- Geochemistry
- Climate Science
Background:
- Permafrost soils harbor microbial communities capable of methanogenesis.
- Understanding microbial activity at low temperatures is critical for climate change and astrobiology.
Purpose of the Study:
- To quantify methanogenesis rates in Siberian permafrost across a temperature range of 5 to -16.5°C.
- To investigate the temperature dependence of methane production from different substrates.
- To assess the viability and potential roles of ancient permafrost microorganisms.
Main Methods:
- Measurement of hydrogenotrophic and acetoclastic methanogenesis using radiolabeled substrates (H14CO3- and 14CH3CO2-).
- Analysis of methane (CH4) production rates at various sub-zero temperatures.
- Application of the Arrhenius equation to determine activation energy.
Main Results:
- Methane formation rates decreased significantly with decreasing temperatures, showing a 2-fold reduction from 5 to -1.8°C.
- A substantial 100-fold reduction in CH4 production was observed between -1.8 and -16.5°C for both substrates.
- Activation energy for methane generation was lower at sub-zero temperatures compared to above-zero temperatures.
Conclusions:
- Permafrost microorganisms remain metabolically active at sub-zero temperatures, influencing greenhouse gas dynamics.
- These cold-adapted microbes play a vital role in nutrient cycling and could be relevant models for extraterrestrial life detection.