Permafrost/Hydrology 2009 LTER Symposium Ted Schuur University of Florida Merritt Turetsky University of Guelph Jay Jones University of Alaska Climate Topography Parent material Time Organisms Ecosystem Dynamics State Factors Humans Permafrost Hydrology Presentation Overview What is the effect of changes in permafrost and hydrologic regime on terrestrial and aquatic ecosystem dynamics? 1. Upland Thermokarst (Schuur; Eight Mile Lake/Healy) 2.Wetlands (Turetsky; APEX/Bonanza Creek Bluff) 3.Upland Streams (Jones; Caribou Poker Creek) Schuur, E.A.G., J. Bockheim, J. Canadell, E. Euskirchen, C.B. Field, S.V Goryachkin, S. Hagemann, P. Kuhry, P. Lafleur, H. Lee, G. Mazhitova, F. E. Nelson, A. Rinke, V. Romanovsky, N. Shiklomanov, C. Tarnocai, S. Venevsky, J. G. Vogel, S.A. Zimov Vulnerability of permafrost carbon to climate change: Implications for the global carbon cycle. BioScience 58: Permafrost Thaw Effects on Ecosystems/Hydrology Global Vegetation C650 Pg Global Soil C (1m)1500 Pg Atmosphere777 Pg Permafrost Zone Soil C Peatlands (several m)277 Pg Mineral Soil (3m)747 Pg Siberian Deep C (~25m) 407 Pg Alluvial Deep C (~25m)241 Pg 1672 Pg Global Carbon Pools [Jobaggy et al. 2000, Field et al. 2007, Zimov et al. 2006, Tarnocai, in press, Schuur et al. 2008] The impact of permafrost thaw on old carbon release and net exchange from tundra Net Ecosystem Exchange (g C m -2 ) Minimal Moderate Extensive sink source Calendar Year Minimal neutral Moderate = sink ( GPP, R eco ) Extensive = source ( GPP, R eco ) Minimal = 66 g m -2 yr -1 Moderate = 40% Extensive = 78% [Schuur et al. in press, Vogel et al., in press] Permafrost Zone Soil C Gelisol Soil Order (3m)818 Pg x % Pg Permafrost C Loss( Pg/yr) Current Land Use Change(1.50.5 Pg/yr) Permafrost Carbon Pool Deep Permafrost C 650 Pg x ? ? Pg [Schuur et al. in press] Hydrologic Carbon Export MinModExt DIC DOC GPP R eco DIC+DOC NEE Annual Flux (g C m -2 yr -1 ) [Sickman et al. in prep] Permafrost Warming Experiment [S. Natali, unpublished data] Climate Soil Gaseous Phase CO 2 /CH 4 fluxes Soil Solid Phase C Storage, Accumulation Vegetation (composition, physiology) Permafrost (hydroclimate, thaw depth, thermokarst) Gradual Warming/snow depth Soil Liquid Phase DOC, DON fluxes C structure and decomposability, Microclimate Redox, Ebullition, Efflux Soil moisture, Redox Thermal Insulation, Storativity Extreme Events Drought/Fire or Deluge/Flooding Conductivity, Connectivity,Redox, Nutrients, ET Themes of current wetland research: How do interactions between vegetation and thaw depth affect the rate and nature of soil organic matter formation? Soil hydroclimate controls (warming, drought, thermokarst) on vegetation, organic matter formation, and carbon/energy balance Approaches currently being used: Experimental manipulation of water table and soil temperature (OTCs, snow depth) Gradient studies along ecotone from black spruce to open peatland Comparative studies across permafrost regimes (peatlands with intact permafrost, thermokarst, no permafrost) Rich fen Black Spruce Willow/Bog Birch Tussock Grass Emergent Marsh Wetland Gradient/Ecotone Rich fen Black Spruce Willow/Bog Birch Tussock Grass Emergent Marsh Wetland Gradient/Ecotone Hydroclimate manipulations CH 4 ~ WT, temp GPP ~ PAR, WT ER ~ WT, temp Veg controls Hydroclimate controls Hydroclimate manipulations Climate Soil moisture/ groundwater flows Soil composition Vegetation (spruce vs. hardwoods; moss) Fire (Frequency & Intensity) Permafrost (extent, thaw depth, thermokarst) Stream hydrology and solutes Fluvial exports CO 2 /CH 4 Redox potential PERMAFROST, HYDROLOGY AND STREAM SOLUTES Task I/S1: Monitoring patterns of retention and loss of water, carbon and nitrogen from watersheds with differing permafrost extent and stability PERMAFROST, HYDROLOGY AND STREAM SOLUTES Hydrograph separation using EMMA (PCA based approach) Four flowpaths: Q1 from soils, Q2, Q3 & Q4 from deeper source waters Soil water dominant source in the C3 stream, Q2 dominant source in C2 and C4 Coupled to patterns in hydrology, the high permafrost watershed has highest DOC, but lowest nitrate concentrations Lower nitrate in the high PF stream indicative that shallow soil not the source of DIN to streams (from Jones et al., in prep)(from Jones et al., 2005) FIRE AND STREAM SOLUTES Fire had a dramatic effect on stream solutes Stream nitrate concentration increased ~130% (SO 4 = and K + also increased) Increase potentially due to reduced competition between vegetation and soil microbes (nitrification), or increase in active layer depth and flushing of deeper stores Stream DOC declined 22% (DON, DOC:DON and Ca 2+ also declined) Decline potentially due to combustion of soil carbon, transformation of soil carbon to less soluble compounds, or decline in soil carbon mineralization (from Betts and Jones, in review) SOURCE WATER AND DOM QUALITY Axis 1 related to reduction-oxidation potential of DOM (oxidized/reduced quinone) Axis 2 related to DOM quality (tyrosine and tryptophan) DOM from thermokarsts of low quality, whereas springs flowing from shallow source waters enriched in labile DOM Within streams, DOM tends to be fairly recalcitrant. Labile DOM rapidly consumed near source DOM composition measured by fluorescence excitation & emission DOM quality measured by one-month bioassays (from Balcarczyk et al., in review)