279-7 Combining a Decade of Results from SPRUCE and Stordalen Mire Sweden to Understand the Processes Controlling Methane Production in peatlands

Session: The Current Understanding of the Role of Wetland Hydrology in the Cycling of Elements and other Substances: A Technical Session in Memory of Paul H. Glaser

Presenting Author:

Jeffrey Chanton

Authors:

Chanton, Jeffrey¹, Wilson, Rachel², Slentz, Alexis³, Smith, Kaley⁴, Varner, Ruth⁵, Rich, Virginia⁶, Kostka, Joel⁷, Crill, Patrick⁸, Tfaily, Malak⁹, Cory, Alexandra¹⁰

(1) Florida State University, Tallahassee, Fl, USA, (2) Florida State University, tallahassee, FL, USA, (3) Florida State University, tallahassee, FL, USA, (4) UNC Chapel Hill, Chapel Hill, NC, USA, (5) UNH, Durhan, NH, USA, (6) Ohio State University, Columbus, OH, USA, (7) Ga Institute of Technology, Atlanta, Ga, USA, (8) Stockholm University, Stockholm, Sweden, (9) University of Arizona, Tucson, AZ, USA, (10) Florida State University, Tallahassee, Fl, USA,

Abstract:

We will summarize lessons learned in observations at two peatlands where we and others have worked for the past 12-15 years, the SPRUCE site in the southern end of the boreal zone (47.5 N, 93.4 W) near Grand Rapids, Minnesota in the Marcell Experimental Forest and Stordalen Mire (68.2 N, 18.5 E) located in northernmost Sweden near Abisko, at the edge of the discontinuous permafrost zone.  At the SPRUCE site, temperature has been manipulated in a series of open top chambers, from ambient to +9C, while at Stordalen Mire, temperatures have increased naturally at twice the global average leading to permafrost thaw, and rapid changes in hydrology and vegetation types.    At the SPRUCE site we have observed increases in the methane/carbon dioxide ratio in porewater consistent with results of in vitro laboratory incubations.  With increasing temperature, the system has become increasingly methanogenic.  Using natural abundance radiocarbon tracing we have also observed increasing decomposition of thousand year old peat at depth leading to increased methane and carbon dioxide production.  At both sites nitrogen is sequestered into organic matter becoming increasingly unavailable.  These reactions have been tied to the reaction of amines with galacturonic acid, a compound produced and released by Sphagnum moss.  In this way, Sphagnum conditions the environment to insure its own success, as it thrives in a more oligotrophic environment.   At Stordalen Mire, increases in decomposition rate and methane production have been driven by changes in ecosystem and vegetation associated with permafrost collapse and associated changes in hydrology.  We have observed a transition from permafrost palsa to collapsed palsa to sphagnum-dominated bog to graminoid-dominated fen.  Associated with these transitions we have quantified increases in net ecosystem production (carbon dioxide uptake) and methane production and emission.  Finally using the considerable data generated at these two well-studied sites, we have compared integrated rates of methane production as measured with in vitro laboratory incubations relative to measured rates of emission at each site and found agreement within a factor of 2.  These findings validate the use of these procedures to explore variations and controls on methane production in organic soils.   

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-4679

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