Plant and Soil

, Volume 412, Issue 1, pp 201–213

Linking rhizospheric CH4 oxidation and net CH4 emissions in an arctic wetland based on 13CH4 labeling of mesocosms

  • Cecilie Skov Nielsen
  • Anders Michelsen
  • Per Ambus
  • T. K. K. Chamindu Deepagoda
  • Bo Elberling
Regular Article

DOI: 10.1007/s11104-016-3061-4

Cite this article as:
Nielsen, C.S., Michelsen, A., Ambus, P. et al. Plant Soil (2017) 412: 201. doi:10.1007/s11104-016-3061-4

Abstract

Aims

Poorly drained arctic ecosystems are potential large emitters of methane (CH4) due to their high soil organic carbon content and low oxygen availability. In wetlands, aerenchymatous plants transport CH4 from the soil to the atmosphere, but concurrently transport O2 to the rhizosphere, which may lead to oxidation of CH4. The importance of the latter process is largely unknown for arctic plant species and ecosystems. Here, we aim to quantify the subsurface oxidation of CH4 in a waterlogged arctic ecosystem dominated by Carex aquatilis ssp. stans and Eriophorum angustifolium, and evaluate the overall effect of these plants on the CH4 budget.

Methods

A mesocosms study was established based on the upper 20 cm of an organic soil profile with intact plants retrieved from a peatland in West Greenland (69°N). We measured dissolved concentrations and emissions of 13CO2 and 13CH4 from mesocosms during three weeks after addition of 13C-enriched CH4 below the mesocosm.

Results

Most of the recovered 13C label (>98 %) escaped the ecosystem as CH4, while less than 2 % was oxidized to 13CO2.

Conclusions

It is concluded that aerenchymatous plants control the overall CH4 emissions but, as a transport system for oxygen, are too inefficient to markedly reduce CH4 emissions.

Keywords

Carex Greenhouse gases Methane Oxidation Stable isotopes Tundra 

Supplementary material

11104_2016_3061_Fig6_ESM.gif (12 kb)
Fig. S1

Redox measurement on mesocosm soil. The dashed line represents approximately the soil surface. Data points are averages and error bars show standard error (GIF 11 kb)

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High Resolution Image (EPS 78 kb)
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Fig. S2

Ecosystem fluxes of a) CH4 (μmol m−2 h−1) and b) CO2 (mmol m−2 h−1). Grey legend filling indicate data from the intensively monitored mesocosm, and black legend filling indicate average data of three replicate mesocosms. Error bars show standard error (GIF 16 kb)

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High Resolution Image (EPS 105 kb)
11104_2016_3061_Fig8_ESM.gif (25 kb)
Fig. S3

Plant fluxes (μmol plant−1 h−1) of a) CH4 and b) CO2. Grey legend filling indicate data from the intensively monitored mesocosm, and black legend filling indicate average data of three replicate mesocosms. Error bars show standard error (GIF 24 kb)

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High Resolution Image (EPS 150 kb)
11104_2016_3061_Fig9_ESM.gif (10 kb)
Fig S4

Fluxes of CH4 and CO2 (μmol plant−1 h−1) from the small Carex shoot (GIF 10 kb)

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High Resolution Image (EPS 72 kb)
11104_2016_3061_Fig10_ESM.gif (26 kb)
Fig. S5

a) Carbon isotope composition of dissolved CH4 (atom% 13C) and b) dissolved CO213C ‰) in the soil water in six depths (down to 18 cm). Data points are averages and error bars show standard error (GIF 26 kb)

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High Resolution Image (EPS 106 kb)
11104_2016_3061_Fig11_ESM.gif (23 kb)
Fig S6

Carbon isotope composition (δ13C ‰) of a) CH4 and b) CO2 emitted from whole mesocosms ecosystem and plants. Data points without error bars are values from the intensively monitored replicate. Data points with error bars are averages of the three replicates. Error bars show standard error (GIF 23 kb)

11104_2016_3061_MOESM6_ESM.eps (152 kb)
High Resolution Image (EPS 152 kb)
11104_2016_3061_Fig12_ESM.gif (15 kb)
Fig S7

Carbon isotope composition (δ13C ‰) of CH4 and CO2 emitted from the small Carex shoot (GIF 14 kb)

11104_2016_3061_MOESM7_ESM.eps (71 kb)
High Resolution Image (EPS 71 kb)
11104_2016_3061_Fig13_ESM.gif (6 kb)
Fig. S8

Cumulated fluxes of excess 13C as CH4 (μg g−1 roots) from the mesocosms. Grey legend filling indicate data from the intensively monitored mesocosm, and black legend filling indicate average data of three replicate mesocosms. Error bars show standard error (GIF 5 kb)

11104_2016_3061_MOESM8_ESM.eps (86 kb)
High Resolution Image (EPS 85 kb)
11104_2016_3061_Fig14_ESM.gif (9 kb)
Fig. S9

Carbon isotope composition (δ13C ‰) of CH4 at 261 h after labeling plotted against soil depth. The curve shows a logarithmic regression. Data points are averages and error bars show standard error (GIF 8 kb)

11104_2016_3061_MOESM9_ESM.eps (63 kb)
High Resolution Image (EPS 62 kb)

Copyright information

© Springer International Publishing Switzerland 2016

Authors and Affiliations

  • Cecilie Skov Nielsen
    • 1
  • Anders Michelsen
    • 1
    • 2
  • Per Ambus
    • 1
  • T. K. K. Chamindu Deepagoda
    • 1
    • 3
  • Bo Elberling
    • 1
  1. 1.Center for Permafrost (CENPERM), Department of Geosciences and Natural Resource ManagementUniversity of CopenhagenCopenhagen KDenmark
  2. 2.Department of BiologyUniversity of CopenhagenCopenhagen ØDenmark
  3. 3.Department of Civil EngineeringUniversity of PeradeniyaPeradeniyaSri Lanka