Hojeong Kang

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Effects of Water Level Drawdown Elevated
Temperature on Peatland Microbes

• Hojeong Kang
• Yonsei University
• Korea
• 2009 TERRECO

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Contents
Backgrounds
1
Water Level Drawdown
2
Temperature rise
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4
Summary
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Backgrounds - Climate Changes Peatlands
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Climate changes include
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Rising temperature (Global)
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IPCC (2007)
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Changes in precipitation 1999 vs. 1900
IPCC (2000)
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Projections of future precipitation
2090-2099
June to August
December to February
IPCC (2007)
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Peatlands

• Accumulation of un-decomposed organic matter as
  peat
• C sink
• 455 Pg C (cf. 750 Pg C in the atmosphere)
• 1/3 of SOM
• Destruction ? CO2, DOC releases
• Excavation for energy source
• Land use changes
• Climate changes

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Classification for peatlands
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Microbes

• Play a key role in peatland biogeochemistry
• CO2, CH4, N2O production
• Decomposition of OM
• Culture-based methods account for only 1-5
• Molecular approaches
• T-RFLP, DGGE
• Realtime Q-PCR
• Sequencing (Cloning, pyrosequencing)

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Objectives

• To determine effects of
• water level drawdown during summer
• warming for 3 years
• on microoganisms in peatland
• Microbial community structure
• Microbial abundance

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Water Level Drawdown
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• Objectives
• Effects of drought on microbial communities in
  wetlands

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• Soil cores collected from three types of wetlands
  (riparian, fen, and bog) in north Wales, UK.

Source Mitch and Gosselink, 2000
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Microcosms
11cm
Surface
20cm
Draining
39 1.4
55 1.7
55 1.2
10cm
4 weeks incubation
Riparian Fen Bog
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Methods

• Analysis of Microbial communities
• Eubacteria (bacterial 16S rRNA genes)
• Denitirifiers (nirS genes)
• Methanogens (mcrA genes)
• Real-Time PCR (Abundance)
• T-RFLP (Diversity, composition)

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T-RFLP (Terminal Restriction Fragment Length
Polymorphism)
(rdp8.cme.msu.edu/html/t-rflp_jul02.html)
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Real Time Q-PCR
(Source Quantabio.com)
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Drought effect Abundance (RT-PCR)
Soil Biology Biochemistry (2008)
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Drought effects Composition
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Drought effects Diversity
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Drought effects Summary
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Change
?()
?
?()
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Summary

• Drought
• Decreased abundance in bog and fen
• No changes in composition
• Various responses in diversity

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Elevated Temperature
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Solardomes
Control Ambient temperature Treatment 3 C
for 3 years
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Warming on peatland (RT-PCR)
Kim et al. (unpublished data)
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Warming effects MRPP test
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Eubacteria


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Methanogen




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Summary
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Water level drawdown

• Decrease in abundance in bog and fen
• No changes in composition
• Various responses in diversity

Elevated temperature
Decrease in methanogen / eubacterial
abundance Changes in eubacterial
community Decreases in diversity of eubacteria
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Acknowledgements

• Prof. C. Freeman, Drs. N. Fenner, S-Y. Kim, S-H.
  Lee
• NRF EcoSTAR for financial supports