A CKNOWLEDGEMENT First and foremost, I would like to thank God for without him truly none of this would have been possible. Thanks to Mr. E. Froburg, NERU collaborators, and NSF for making this research experience possible. To Ms. Kaitlyn Steele, I most graciously appreciate the selflessness actions and contributions to the overall success of the NERU Figures 1- 4 provided by Maria Paula (MP) Mugnani..Figures 5 & 6 provided by Dr. Ruth K. Varner. This research was supported through the Northern Ecosystems Research for Undergraduates (NERU) program (NSF REU site EAR# ). A CKNOWLEDGEMENT First and foremost, I would like to thank God for without him truly none of this would have been possible. Thanks to Mr. E. Froburg, NERU collaborators, and NSF for making this research experience possible. To Ms. Kaitlyn Steele, I most graciously appreciate the selflessness actions and contributions to the overall success of the NERU Figures 1- 4 provided by Maria Paula (MP) Mugnani..Figures 5 & 6 provided by Dr. Ruth K. Varner. This research was supported through the Northern Ecosystems Research for Undergraduates (NERU) program (NSF REU site EAR# ). R ESEARCH F IELD S ITE  Stordalen Mire near Abisko, Sweden (68°21' N, 19°03' E) (Figure 1, shown below)  Primarily composed of three different ecosystems: I.Elevated, dry palsa underlain by permafrost) (Figure 2) II.Intermediate moisture site dominated by Sphagnum spp. (Figure 3) III.Completely thawed wet site dominated by Eriophorum spp. (Figure 4) R ESEARCH F IELD S ITE  Stordalen Mire near Abisko, Sweden (68°21' N, 19°03' E) (Figure 1, shown below)  Primarily composed of three different ecosystems: I.Elevated, dry palsa underlain by permafrost) (Figure 2) II.Intermediate moisture site dominated by Sphagnum spp. (Figure 3) III.Completely thawed wet site dominated by Eriophorum spp. (Figure 4) R ESEARCH O BJECTIVES  Examine the dynamics of CO 2  Net ecosystem exchange (NEE)  Respiration  Gross Primary Production (GPP)  Examine CH 4 exchange  Flux measurements  Measure δ 13 C-CH 4 of emitted CH 4 R ESEARCH O BJECTIVES  Examine the dynamics of CO 2  Net ecosystem exchange (NEE)  Respiration  Gross Primary Production (GPP)  Examine CH 4 exchange  Flux measurements  Measure δ 13 C-CH 4 of emitted CH 4 I NTRODUCTION  Northern peatlands currently store ~30% of the world’s soil carbon and are the largest single natural source of atmospheric methane (CH 4 )  Since 2000, the Swedish sub-Arctic mean annual temperature has crossed the significant 0  C threshold 1  As the climate warms, possible positive feedbacks driven by changes in peatland carbon dioxide (CO 2 ) and CH 4 cycling could have major impacts on  the atmospheric concentrations of both greenhouse gases 2  cryospheric and ecological processes 1  Methane has 62 times the global warming potential (GWP) of CO 2 at 20 year timescales 3  In wetland systems, CH 4 emissions are highly variable (both spatially and temporally) 4,5  In terrestrial freshwater systems, CH 4 is formed by two main pathways: I.CH 3 COOH → CH 4 + CO 2 II.2CH 2 O + 2H 2 O → 2CO 2 + 4H 2 CO 2 + 4H 2 → CH 4 + 2H 2 O III.2CH 2 O → CH 4 + CO 2 I NTRODUCTION  Northern peatlands currently store ~30% of the world’s soil carbon and are the largest single natural source of atmospheric methane (CH 4 )  Since 2000, the Swedish sub-Arctic mean annual temperature has crossed the significant 0  C threshold 1  As the climate warms, possible positive feedbacks driven by changes in peatland carbon dioxide (CO 2 ) and CH 4 cycling could have major impacts on  the atmospheric concentrations of both greenhouse gases 2  cryospheric and ecological processes 1  Methane has 62 times the global warming potential (GWP) of CO 2 at 20 year timescales 3  In wetland systems, CH 4 emissions are highly variable (both spatially and temporally) 4,5  In terrestrial freshwater systems, CH 4 is formed by two main pathways: I.CH 3 COOH → CH 4 + CO 2 II.2CH 2 O + 2H 2 O → 2CO 2 + 4H 2 CO 2 + 4H 2 → CH 4 + 2H 2 O III.2CH 2 O → CH 4 + CO 2 Equation II: Reduction of CO 2 with Hydrogen; dominates Sphagnum sites 7 R ESULTS Automatic Chamber Measurements of Methane and Carbon Dioxide Fluxes and Isotopologues of CH 4 in a sub-Arctic Mire Ryan D. Lawrence 1*, Carmody K. McCalley 2, Patrick M. Crill 3, Ruth K. Varner 4, Scott R. Saleska 2 1 Department of Chemistry, Geology, and Physics, Elizabeth City State University, Elizabeth City, NC 27909, USA. 2 Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ 85719, USA. 3 Department of Geological Sciences, University of Stockholm, Svante Arrhenius Va ̈ g 8 C, SE Stockholm, Sweden. 4 Climate Change Research Center, Institute for the Study of Earth, Oceans and Space, Morse Hall, University of New Hampshire, Durham, NH 03824, USA. Automatic Chamber Measurements of Methane and Carbon Dioxide Fluxes and Isotopologues of CH 4 in a sub-Arctic Mire Ryan D. Lawrence 1*, Carmody K. McCalley 2, Patrick M. Crill 3, Ruth K. Varner 4, Scott R. Saleska 2 1 Department of Chemistry, Geology, and Physics, Elizabeth City State University, Elizabeth City, NC 27909, USA. 2 Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ 85719, USA. 3 Department of Geological Sciences, University of Stockholm, Svante Arrhenius Va ̈ g 8 C, SE Stockholm, Sweden. 4 Climate Change Research Center, Institute for the Study of Earth, Oceans and Space, Morse Hall, University of New Hampshire, Durham, NH 03824, USA. C ONCLUSION  As the landscape transitions from a dry palsa, underlain by permafrost, to a predominately wet site dominated by Eriophorum spp. I.Sequestration of CO 2 II.Increasing amount of CH 4 to the atmosphere  The average carbon isotope composition of emitted CH 4 was -68 ‰ at the Sphagnum site compared to -62 ‰ at the Eriophorum site I.Depicts relative shift from CO 2 -reductive towards acetate fermentation 6  Isotopic signature of derive CH 4 appears to not be affected by light conditions C ONCLUSION  As the landscape transitions from a dry palsa, underlain by permafrost, to a predominately wet site dominated by Eriophorum spp. I.Sequestration of CO 2 II.Increasing amount of CH 4 to the atmosphere  The average carbon isotope composition of emitted CH 4 was -68 ‰ at the Sphagnum site compared to -62 ‰ at the Eriophorum site I.Depicts relative shift from CO 2 -reductive towards acetate fermentation 6  Isotopic signature of derive CH 4 appears to not be affected by light conditions M ETHODOLOGY  Individual automated chamber measurements were conducted using two 5 minute interval lid closures, under two different light conditions: I.Ambient light [transparent chamber] (Figure 5*) II.Darkened [shrouded chamber] (Figure 6)  δ 13 C-CH 4 was determined using a Quantum Cascade Laser Spectrometer (QCL)  Methane isotopic composition derived from Keeling regressions of isotope and concentration data from automated chamber flux measurement M ETHODOLOGY  Individual automated chamber measurements were conducted using two 5 minute interval lid closures, under two different light conditions: I.Ambient light [transparent chamber] (Figure 5*) II.Darkened [shrouded chamber] (Figure 6)  δ 13 C-CH 4 was determined using a Quantum Cascade Laser Spectrometer (QCL)  Methane isotopic composition derived from Keeling regressions of isotope and concentration data from automated chamber flux measurement Table III. Automated Chamber Measurements F UTURE WORK  More measurements should be conducted, especially during the 21:00 – 03:00 time period  larger data sets will begin to offset the the high variability of CH 4 emissions  provide more information about potential impact of light on δ 13 C-CH 4  Collect active layer depth 8, water table depth 4,9, chamber plant species composition by percent cover 8,6, and pH 8 if suitable for site  Aforementioned variables shown to affect CH 4 exchange and CO 2 dynamics  Further analyze data using a statistical package, such as SPSS or SAS  Example : paired t-test of average day vs. night δ 13 C-CH 4 to determine if isotopic composition of derived CH 4 source is affected by light F UTURE WORK  More measurements should be conducted, especially during the 21:00 – 03:00 time period  larger data sets will begin to offset the the high variability of CH 4 emissions  provide more information about potential impact of light on δ 13 C-CH 4  Collect active layer depth 8, water table depth 4,9, chamber plant species composition by percent cover 8,6, and pH 8 if suitable for site  Aforementioned variables shown to affect CH 4 exchange and CO 2 dynamics  Further analyze data using a statistical package, such as SPSS or SAS  Example : paired t-test of average day vs. night δ 13 C-CH 4 to determine if isotopic composition of derived CH 4 source is affected by light R EFERENCES [1] Callaghan, T. V., F. Bergholm, T. R. Christensen, C. Jonasson, U. Kokfelt, and M. Johansson (2010), A new climate era in the sub-Arctic: Accelerating climate changes and multiple impacts, Geophys. Res. Lett., 37, L14705, doi: /2009GL [2] Nykänen, H., J. E. P. Heikkinen, L. Pirinen, K. Tiilikainen, and P. J. Martikainen (2003), Annual CO 2 exchange and CH 4 fluxes on a subarctic palsa mire during climatically different years, Global Biogeochem. Cycles, 17(1), 1018, doi: /2002GB [3] Houghton, J. T., Y. Ding, D. J. Griggs, M. Noguer, P. J. van der Winden, and X. Dai (2001), Climate Change 2001: The Scientific Basis. Contri- bution of Working Group 1 to the Third Assessment Report, Cambridge Univ. Press, New York. [4] Bubier, J., T. Moore, K. Savage, and P. Crill (2005), A comparison of methane flux in a boreal landscape between a dry and a wet year, Global Biogeochem. Cycles, 19, GB1023, doi: /2004GB [5] Joabsson, A., and T. R. Christensen (2001), Methane emissions from wet- lands and their relationship with vascular plants: An Arctic example, Global Change Biol., 7(8), 919–932 [6] Bäckstrand, K., Crill, P. M., Jackowicz-Korczyñski, M., Mastepanov, M., Christensen, T. R., and Bastviken, D. (2009), Annual carbon gas budget for a subarctic peatland, northern Sweden, Biogeosciences Discuss., 6, , doi: /bgd [6] Whiticar M.J. (1999), Carbon and hydrogen isotope systematics of bacterial formation and oxidation of methane. Chem Geol 161: [7] Lansdown J. M., Quay E D. and King S. L. (1992), CH 4 production via CO 2 reduction in a temperate bog: A source of 13 C depleted CH 4. GeochimCosmochimActa 56: [8] Bubier, J. L., T. R. Moore, L. Bellisario, N. T. Comer, and P. M. Crill (1995), Ecological controls on methane emissions from a Northern peatland complex in the zone of discontinuous permafrost, Manitoba, Canada, Global Biogeochem. Cycles, 9(4), 455–470. [9] Updegraff, K. (2001), Response of CO 2 and CH 4 emissions from peatlands to warming and water table manipulation, Ecol. Appl., 11(2), 311–326. R EFERENCES [1] Callaghan, T. V., F. Bergholm, T. R. Christensen, C. Jonasson, U. Kokfelt, and M. Johansson (2010), A new climate era in the sub-Arctic: Accelerating climate changes and multiple impacts, Geophys. Res. Lett., 37, L14705, doi: /2009GL [2] Nykänen, H., J. E. P. Heikkinen, L. Pirinen, K. Tiilikainen, and P. J. Martikainen (2003), Annual CO 2 exchange and CH 4 fluxes on a subarctic palsa mire during climatically different years, Global Biogeochem. Cycles, 17(1), 1018, doi: /2002GB [3] Houghton, J. T., Y. Ding, D. J. Griggs, M. Noguer, P. J. van der Winden, and X. Dai (2001), Climate Change 2001: The Scientific Basis. Contri- bution of Working Group 1 to the Third Assessment Report, Cambridge Univ. Press, New York. [4] Bubier, J., T. Moore, K. Savage, and P. Crill (2005), A comparison of methane flux in a boreal landscape between a dry and a wet year, Global Biogeochem. Cycles, 19, GB1023, doi: /2004GB [5] Joabsson, A., and T. R. Christensen (2001), Methane emissions from wet- lands and their relationship with vascular plants: An Arctic example, Global Change Biol., 7(8), 919–932 [6] Bäckstrand, K., Crill, P. M., Jackowicz-Korczyñski, M., Mastepanov, M., Christensen, T. R., and Bastviken, D. (2009), Annual carbon gas budget for a subarctic peatland, northern Sweden, Biogeosciences Discuss., 6, , doi: /bgd [6] Whiticar M.J. (1999), Carbon and hydrogen isotope systematics of bacterial formation and oxidation of methane. Chem Geol 161: [7] Lansdown J. M., Quay E D. and King S. L. (1992), CH 4 production via CO 2 reduction in a temperate bog: A source of 13 C depleted CH 4. GeochimCosmochimActa 56: [8] Bubier, J. L., T. R. Moore, L. Bellisario, N. T. Comer, and P. M. Crill (1995), Ecological controls on methane emissions from a Northern peatland complex in the zone of discontinuous permafrost, Manitoba, Canada, Global Biogeochem. Cycles, 9(4), 455–470. [9] Updegraff, K. (2001), Response of CO 2 and CH 4 emissions from peatlands to warming and water table manipulation, Ecol. Appl., 11(2), 311–326. Equation I: Acetate Fermentation; dominates freshwater systems 6 / Eriophorum sites 7 Equation III: Overall reaction encompassing both pathways of CH 4 production Table II. Sample Time Period Table I. Automated Chamber Ecosystem * In addition, entire automated chamber system was calibrated every 90 minutes. * One complete cycle (Chamber 1-9) is three hours. Fig. 2) Fig. 5 Ambient light chamber *chamber lid open in photo Fig. 6 Darkened chamber Fig. 3)Fig. 4) Figure 7) GPP was calculated using the equation GPP = NEE – respiration. From permafrost to Eriophorum, more plants result in overall uptake of CO 2. Figure 8) Methane flux measurements were made under ambient light and shrouded conditions. Differences in CH 4 emission occur; however, high variability and small sample size may reason that result in observed change. Figure 9 & 10) The averages of all δ 13 C-CH 4 within each cover type are similar; however, measurements conducted during the hours of 09:00 – 15:00 vs. 21:00 – 03:00 may potentially be significantly different. Yet, CH 4 high variability may heavily influence results of small sample size (n = 24).