Linking rhizospheric CH4 oxidation and net CH4 emissions in an arctic wetland based on 13CH4 labeling of mesocosms
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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.
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.
Most of the recovered 13C label (>98 %) escaped the ecosystem as CH4, while less than 2 % was oxidized to 13CO2.
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.
KeywordsCarex Greenhouse gases Methane Oxidation Stable isotopes Tundra
The Danish National Research Foundation is gratefully acknowledged for the funding of this study through the funding of CENPERM (DNRF100). We thank Frida Lindwall and Nynne Rand Ravn for peat block collection and transport to Copenhagen, Katrine Wulff for help during the incubation experiments, and technicians at CENPERM for help with analyses.
- Askaer L, Elberling B, Glud RN, Kuhl M, Lauritsen FR, Joensen HR (2010) Soil heterogeneity effects on O2 distribution and CH4 emissions from wetlands: In situ and mesocosm studies with planar O2 optodes and membrane inlet mass spectrometry. Soil Biol Biochem 42:2254–2265. doi: 10.1016/j.soilbio.2010.08.026 CrossRefGoogle Scholar
- Christiansen J, Romero A, Jørgensen NG, Glaring M, Jørgensen C, Berg L, Elberling B (2014) Methane fluxes and the functional groups of methanotrophs and methanogens in a young Arctic landscape on Disko Island, West Greenland. Biogeochemistry: 1–19. doi: 10.1007/s10533-014-0026-7
- Collins M, Knutti R, Arblaster J, Dufresne J-L, Fichefet T, Friedlingstein P, Gao X, Gutowski WJ, Johns T, Krinner G, Shongwe M, Tebaldi C, Weaver AJ, Wehner M (2013) Long-term climate change: projections, commitments and irreversibility. In: Stocker TF, Qin D, Plattner G-K, Tignor M, Allen SK, Boschung J, Nauels A, Xia Y, Bex V, Midgley PM (eds) Climate change 2013: The physical science basis contribution of working group I to the fifth assessment report of the intergovernmental panel on climate change. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USAGoogle Scholar
- D’Imperio L, Nielsen CS, Westergaard-Nielsen A, Michelsen A, Elberling B (2016) Methane oxidation in contrasting soil types: responses to experimental warming with implication for landscape-integrated CH4 budget. Glob Chang Biol. doi: 10.1111/gcb.13400
- Elberling B, Nordstrøm C, Grøndahl L, Søgaard H, Friborg T, Christensen TR, Ström L, Marchand F, Nijs I (2008) High-arctic soil CO2 and CH4 production controlled by temperature, water, freezing and snow. In: Meltofte H, Christensen TR, Elberling B, Forchhammer MC, Rasch M (eds) Advances in ecological research, Vol 40: High-Arctic ecosystem dynamics in a changing climate. Elsevier Academic Press Inc, San DiegoGoogle Scholar
- Hartmann DL, Klein Tank AMG, Rusticucci M, Alexander LV, Brönnimann S, Charabi Y, Dentener FJ, Dlugokencky EJ, Easterling DR, Kaplan A, Soden BJ, Thorne PW, Wild M, Zhai PM (2013) Observations: atmosphere and surface. In: Stocker TF, Qin D, Plattner G-K, Tignor M, Allen SK, Boschung J, Nauels A, Xia Y, Bex V, Midgley PM (eds) Climate change 2013: The physical science basis contribution of working group I to the fifth assessment report of the intergovernmental panel on climate change. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USAGoogle Scholar
- Johnston CE, Ewing SA, Harden JW, Varner RK, Wickland KP, Koch JC, Fuller CC, Manies K, Jorgenson MT (2014) Effect of permafrost thaw on CO2 and CH4 exchange in a western Alaska peatland chronosequence. Environ Res Lett 9. doi: 10.1088/1748-9326/9/8/085004
- King JY, King JY, Reeburgh WS, Reeburgh WS, Regli SK, Regli SK (1998) Methane emission and transport by arctic sedges in Alaska: Results of a vegetation removal experimentGoogle Scholar
- Michelsen A, Graglia E, Schmidt IK, Jonasson S, Sleep D, Quarmby C (1999) Differential responses of grass and a dwarf shrub to long-term changes in soil microbial biomass C, N and P following factorial addition of NPK fertilizer, fungicide and labile carbon to a heath. New Phytol 143:523–538. doi: 10.1046/j.1469-8137.1999.00479.x CrossRefGoogle Scholar
- Schuur EAG, McGuire AD, Schädel C, Grosse G, Harden JW, Hayes DJ, Hugelius G, Koven CD, Kuhry P, Lawrence DM, Natali SM, Olefeldt D, Romanovsky VE, Schaefer K, Turetsky MR, Treat CC, Vonk JE (2015) Climate change and the permafrost carbon feedback. Nature 520(7546):171–179CrossRefPubMedGoogle Scholar
- Tagesson T, Molder M, Mastepanov M, Sigsgaard C, Tamstorf MP, Lund M, Falk JM, Lindroth A, Christensen TR, Strom L (2012) Land-atmosphere exchange of methane from soil thawing to soil freezing in a high-Arctic wet tundra ecosystem. Glob Chang Biol 18:1928–1940. doi: 10.1111/j.1365-2486.2012.02647.x CrossRefGoogle Scholar