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Aerobic carbon-cycle related microbial communities in boreal peatlands: responses to water-level drawdown

Thesis/Dissertation:

Abstract

Boreal peatlands represent a considerable portion of the global carbon (C) pool. Water-level drawdown (WLD) causes peatland drying and induces a vegetation change, which affects the decomposition of soil organic matter and the release of greenhouse gases (CO{sub 2} and CH{sub 4}). The objective of this thesis was to study the microbial communities related to the C cycle and their response to WLD in two boreal peatlands. Both sampling depth and site type had a strong impact on all microbial communities. In general, bacteria dominated the deeper layers of the nutrient-rich fen and the wettest surfaces of the nutrient-poor bog sites, whereas fungi seemed more abundant in the drier surfaces of the bog. WLD clearly affected the microbial communities but the effect was dependent on site type. The fungal and methane-oxidizing bacteria (MOB) community composition changed at all sites but the actinobacterial community response was apparent only in the fen after WLD. Microbial communities became more similar among sites after long-term WLD. Litter quality had a large impact on community composition, whereas the effects of site type and WLD were relatively minor. The decomposition rate of fresh organic matter was influenced slightly by actinobacteria, but not at all by fungi.  More>>
Authors:
Publication Date:
Jul 01, 2010
Product Type:
Thesis/Dissertation
Resource Relation:
Other Information: Thesis or Dissertation; TH: Thesis (Ph.D.); 244 refs. Dissertationes forestales 101. The thesis includes also 5 previous publications published elsewhere
Subject:
54 ENVIRONMENTAL SCIENCES; WETLANDS; CARBON CYCLE; AQUATIC ECOSYSTEMS; PLANTS; MICROORGANISMS; RESPIRATION; METHANE; CARBON DIOXIDE; BOREAL REGIONS
OSTI ID:
1008044
Research Organizations:
Helsinki Univ. (Finland). Dept. of Biosciences
Country of Origin:
Finland
Language:
English
Other Identifying Numbers:
Other: ISBN 978-951-651-292-4; ISBN 978-951-651-291-7; TRN: FI1103012
Availability:
Available in fulltext at http://www.metla.fi/dissertationes/df101.pdf
Submitting Site:
FI
Size:
53 p. pages
Announcement Date:
Mar 14, 2011

Thesis/Dissertation:

Citation Formats

Peltoniemi, K. Aerobic carbon-cycle related microbial communities in boreal peatlands: responses to water-level drawdown. Finland: N. p., 2010. Web.
Peltoniemi, K. Aerobic carbon-cycle related microbial communities in boreal peatlands: responses to water-level drawdown. Finland.
Peltoniemi, K. 2010. "Aerobic carbon-cycle related microbial communities in boreal peatlands: responses to water-level drawdown." Finland.
@misc{etde_1008044,
title = {Aerobic carbon-cycle related microbial communities in boreal peatlands: responses to water-level drawdown}
author = {Peltoniemi, K}
abstractNote = {Boreal peatlands represent a considerable portion of the global carbon (C) pool. Water-level drawdown (WLD) causes peatland drying and induces a vegetation change, which affects the decomposition of soil organic matter and the release of greenhouse gases (CO{sub 2} and CH{sub 4}). The objective of this thesis was to study the microbial communities related to the C cycle and their response to WLD in two boreal peatlands. Both sampling depth and site type had a strong impact on all microbial communities. In general, bacteria dominated the deeper layers of the nutrient-rich fen and the wettest surfaces of the nutrient-poor bog sites, whereas fungi seemed more abundant in the drier surfaces of the bog. WLD clearly affected the microbial communities but the effect was dependent on site type. The fungal and methane-oxidizing bacteria (MOB) community composition changed at all sites but the actinobacterial community response was apparent only in the fen after WLD. Microbial communities became more similar among sites after long-term WLD. Litter quality had a large impact on community composition, whereas the effects of site type and WLD were relatively minor. The decomposition rate of fresh organic matter was influenced slightly by actinobacteria, but not at all by fungi. Field respiration measurements in the northern fen indicated that WLD accelerates the decomposition of soil organic matter. In addition, a correlation between activity and certain fungal sequences indicated that community composition affects the decomposition of older organic matter in deeper peat layers. WLD had a negative impact on CH{sub 4} oxidation, especially in the oligotrophic fen. Fungal sequences were matched to taxa capable of utilizing a broad range of substrates. Most of the actinobacterial sequences could not be matched to characterized taxa in reference databases. This thesis represents the first investigation of microbial communities and their response to WLD among a variety of boreal peatland habitats. The results indicate that microbial community responses to WLD are complex but dependent on peatland type, litter quality, depth, and variable among microbes. (orig.)}
place = {Finland}
year = {2010}
month = {Jul}
}