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Presence of Eriophorum scheuchzeri enhances substrate availability and methane emission in an Arctic wetland

Ström, Lena LU ; Tagesson, Torbern LU ; Mastepanov, Mikhail LU and Christensen, Torben LU (2012) In Soil Biology & Biochemistry 45. p.61-70
Abstract
Here we present results from a field experiment in an Arctic wetland situated in Zackenberg, NE Greenland. During one growing season we investigated how dominance of the sedge Eriophorum scheuchzeri affected the below-ground concentrations of low molecular weight carbon compounds (LMWOC) and the fluxes of CO2 and CH4 in comparison to dominance of other sedges (Carex stans and Dupontia psilosantha). Three groups of LMWOC were analysed using liquid chromatography-ionspray tandem mass spectrometry, i.e., organic acids (OAs), amino acids (AAs) and simple carbohydrates (CHs). To identify the effect of plant composition the experiments were carried out in a continuous fen area with very little between species variation in environmental... (More)
Here we present results from a field experiment in an Arctic wetland situated in Zackenberg, NE Greenland. During one growing season we investigated how dominance of the sedge Eriophorum scheuchzeri affected the below-ground concentrations of low molecular weight carbon compounds (LMWOC) and the fluxes of CO2 and CH4 in comparison to dominance of other sedges (Carex stans and Dupontia psilosantha). Three groups of LMWOC were analysed using liquid chromatography-ionspray tandem mass spectrometry, i.e., organic acids (OAs), amino acids (AAs) and simple carbohydrates (CHs). To identify the effect of plant composition the experiments were carried out in a continuous fen area with very little between species variation in environmental conditions, e.g., water-table and active layer thickness and soil temperature. The pool of labile LMWOC compounds in this Arctic fen was dominated by OAs, constituting between 75 and 83% of the total pore water pool of OAs. CHs and Ms. The dominant OA was acetic acid, an easily available substrate for methanogens, which constituted >= 85% of the OA pool. We estimated that the concentration of acetic acid found in pore water would support 2 -2.5 h of CH4 flux and an additional continuous input of acetic acid through root exudation that would support 1.3-1.5 h of CH4 flux. Thus, the results clearly points to the importance of a continuous input for acetoclastic methanogenesis to be sustainable. Additionally, Eriophorum had a very strong effect on parts of the carbon cycle in the Arctic fen. The mean seasonal CH4 flux was twice as high in Eriophorum dominated plots, most likely due to a 1.7 times higher concentration of OAs in these plots. Further, the ecosystem respiration was 1.3 times higher in Eriophorum dominated plots. In conclusion, the results offer further support to the importance of certain vascular plant species for the carbon cycle of wetland ecosystems. (C) 2011 Elsevier Ltd. All rights reserved. (Less)
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author
organization
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type
Contribution to journal
publication status
published
subject
keywords
Organic acids, Carbohydrates, Amino acids, Wetlands, Arctic, CO2 flux, CH4 flux, Eriophorum, Dupontia, Carex
in
Soil Biology & Biochemistry
volume
45
pages
61 - 70
publisher
Elsevier
external identifiers
  • wos:000299983700008
  • scopus:80755148740
ISSN
0038-0717
DOI
10.1016/j.soilbio.2011.09.005
project
BECC
MERGE
language
English
LU publication?
yes
id
5ac73443-26c2-4de6-83de-e7c8c16bab5d (old id 2409845)
date added to LUP
2012-03-28 11:04:59
date last changed
2017-11-05 04:09:03
@article{5ac73443-26c2-4de6-83de-e7c8c16bab5d,
  abstract     = {Here we present results from a field experiment in an Arctic wetland situated in Zackenberg, NE Greenland. During one growing season we investigated how dominance of the sedge Eriophorum scheuchzeri affected the below-ground concentrations of low molecular weight carbon compounds (LMWOC) and the fluxes of CO2 and CH4 in comparison to dominance of other sedges (Carex stans and Dupontia psilosantha). Three groups of LMWOC were analysed using liquid chromatography-ionspray tandem mass spectrometry, i.e., organic acids (OAs), amino acids (AAs) and simple carbohydrates (CHs). To identify the effect of plant composition the experiments were carried out in a continuous fen area with very little between species variation in environmental conditions, e.g., water-table and active layer thickness and soil temperature. The pool of labile LMWOC compounds in this Arctic fen was dominated by OAs, constituting between 75 and 83% of the total pore water pool of OAs. CHs and Ms. The dominant OA was acetic acid, an easily available substrate for methanogens, which constituted >= 85% of the OA pool. We estimated that the concentration of acetic acid found in pore water would support 2 -2.5 h of CH4 flux and an additional continuous input of acetic acid through root exudation that would support 1.3-1.5 h of CH4 flux. Thus, the results clearly points to the importance of a continuous input for acetoclastic methanogenesis to be sustainable. Additionally, Eriophorum had a very strong effect on parts of the carbon cycle in the Arctic fen. The mean seasonal CH4 flux was twice as high in Eriophorum dominated plots, most likely due to a 1.7 times higher concentration of OAs in these plots. Further, the ecosystem respiration was 1.3 times higher in Eriophorum dominated plots. In conclusion, the results offer further support to the importance of certain vascular plant species for the carbon cycle of wetland ecosystems. (C) 2011 Elsevier Ltd. All rights reserved.},
  author       = {Ström, Lena and Tagesson, Torbern and Mastepanov, Mikhail and Christensen, Torben},
  issn         = {0038-0717},
  keyword      = {Organic acids,Carbohydrates,Amino acids,Wetlands,Arctic,CO2 flux,CH4 flux,Eriophorum,Dupontia,Carex},
  language     = {eng},
  pages        = {61--70},
  publisher    = {Elsevier},
  series       = {Soil Biology & Biochemistry},
  title        = {Presence of Eriophorum scheuchzeri enhances substrate availability and methane emission in an Arctic wetland},
  url          = {http://dx.doi.org/10.1016/j.soilbio.2011.09.005},
  volume       = {45},
  year         = {2012},
}