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How often and under what circumstances does wetland drying or thawing of permafrost cause a change in ecosystem state? How often and under what circumstances.

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Presentation on theme: "How often and under what circumstances does wetland drying or thawing of permafrost cause a change in ecosystem state? How often and under what circumstances."— Presentation transcript:

1 How often and under what circumstances does wetland drying or thawing of permafrost cause a change in ecosystem state? How often and under what circumstances does wetland drying or thawing of permafrost cause a change in ecosystem state?

2 Crossing the final ecological threshold in high Arctic ponds Smol and Douglas 2007 PNAS

3 Barber et al. 2004 Climatic Change

4 Klein et al. Can. J. For. Res. 2005

5 Burn, C. R. 2005 Permafrost and Periglac. Process.

6 Yoshikawa and Hinzman 2003 Permafrost and Periglac. Process.

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8 Smith et al. 2005 Science “Disappearing Arctic Lakes”

9 Riordan et al. JGR 2006

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11 Yoshikawa et al.2002 JGR

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14 15-June-1986 Image

15 16-June-2001 Image

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17 1988 Burn

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19 25-June-2001

20 28-June-2005

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24 Consequences of a changing hydroclimate for organic-rich wetlands CZEN

25 Plant fixation and allocation Peat accumulation Climate Microbial metabolism

26 www.apex.msu.edu

27 APEX Gradient sites Rich fen Black Spruce Willow/Bog Birch Tussock Grass Emergent

28 LoweredControlRaised www.apex.msu.e du

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33 NEE (mol m -2 s -1 ) PAR (mol m -2 s -1 ) Raised Control Lowered Light response curves

34 ET & plant responses to water table treatments www.apex.msu.edu

35 mol CH 4 m -2 min -1 0 1 2 3 4 5 6 7 8 ControlLoweredRaised c cd d e a b warming Coupled carbon – water dynamics CH 4 flux sensitive to soil hydroclimate (Treat et al. in review) no warming

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38 050100150200250 100 150 200 300 350 400 450 250 Annual organic matter storage (g organic matter m -2 yr -1 ) Time since permafrost degradation Turetsky et al. 2006

39 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 3/204/94/295/196/86/287/188/78/279/1610/6 Permafrost Plateau Thermokarst Edges Thermokarst Wetlands mmol CH 4 m -2 hr -1 Methane Fluxes, 2003 *Each point is the mean ± one standard deviation of one to five measurements. Measurements on 3/25 were made in 2004. Measurements on 3/25 were made in 2004. Wickland et al., 2006

40 Flashier! Wetland ecohydrology can be surprising Vegetation -> peat properties -> hydrology


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