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[Nitrogen-fixing activity in peat soils from a raised bog]
I K Kravchenko1, E V Doroshenko
1Institute of Microbiology, Russian Academy of Sciences, pr. 60-letiya Oktyabrya 7, k. 2, Moscow, 117312 Russia. kravchen@inmi.da.ru
Mikrobiologiia
|April 18, 2003
Summary
Nitrogen fixation in peat soils is low but can be significantly enhanced by glucose addition, stimulating nitrogenase activity. This process occurs across a broad pH and temperature range, with methanol-utilizing bacteria being dominant.
Area of Science:
- Environmental microbiology
- Soil science
- Biogeochemistry
Context:
- Peat soils are crucial ecosystems with complex microbial communities.
- Nitrogen cycling in peatlands is vital for overall ecosystem health and function.
- Understanding nitrogen fixation mechanisms in peat is essential for soil fertility and carbon sequestration.
Purpose:
- To quantify nitrogenase activity in peat samples.
- To investigate the impact of glucose on nitrogen fixation.
- To determine optimal environmental conditions for nitrogen fixation in peat.
- To identify dominant nitrogen-fixing bacteria in peat soils.
Summary:
- Nitrogenase (acetylene reductase) activity in peat was low (0.014-0.022 mg N/kg/h), with 15N2 incorporation ranging from 2.71-8.13 mg N/kg over 15 days.
- Nitrogen fixation peaked in the 10-20 cm soil layer and was stimulated by glucose addition, with repeated glucose application yielding higher activity (8.5 mg N/kg/h).
- Optimal conditions for nitrogen fixation included a wide pH range (3.0-7.5) and temperatures (5-35°C), with diazotrophic methanol-utilizing bacteria being the most abundant group.
Impact:
- This study quantifies nitrogen fixation rates in peat soils and identifies key factors influencing this process.
- Findings highlight the potential for enhancing nitrogen fixation in peatlands through organic amendments like glucose.
- Identifies dominant nitrogen-fixing microbial groups, informing future research on peatland microbial ecology and biogeochemical cycling.