Inter-annual carbon dioxide uptake of a wet sedge tundra ecosystem in the Arctic

The CO2 flux of a wet sedge tundra ecosystem in the Arctic, at Barrow, Alaska, has been measured by the eddy correlation method since spring 1999, and the CO2 uptake by the vegetation during the spring and growing periods was examined between 1999 and 2000. CO2 flux changed to a sink immediately after the spring thaw in 1999 and the photosynthetic activity was high in the first half of the growing period. At this time the air temperature was low and solar radiation was high. In the 2000 season, the temperature was approximately 5°C lower during the snow-covered period, and increased up to 5 oC higher right after the spring thaw but the solar radiation decreased to two thirds of that in 1999. Thus, we found different CO2 accumulation during the snowmelt and the following two weeks between both years. The difference in the climate at beginning shoulder period of the growing season resulted in the difference of CO2 accumulation through the growing period. The maximum level of photosynthetic potential (Pmax) in late July was analyzed as being almost the same at 20 gCO2 m−2 d−1 for both years. However, the weekly average peak CO2 uptake was 16.4 and 11.9 gCO2 m−2 d−1 in 1999 and 2000, respectively, with the lower number in 2000 caused by the low radiation with high air temperatures. The CO2 accumulation during the spring and through the growing periods was a net sink of 593 gCO2 m−2 in 1999 and a sink of 384 gCO2 m−2 in 2000. High CO2 accumulation in 1999 was caused by earlier development of the vegetation, and the lower CO2 uptake in mid summer in 2000 was caused by unseasonable weather.

[1]  K. E. Moore,et al.  Environmental controls on the photosynthesis and respiration of a boreal lichen woodland: a growing season of whole-ecosystem exchange measurements by eddy correlation , 1995, Oecologia.

[2]  P. Bartlett,et al.  Interannual variability in carbon dioxide exchanges at a boreal wetland in the BOREAS northern study area , 1999 .

[3]  M. Sturm,et al.  Structure and wind transport of seasonal snow on the Arctic slope , 1993 .

[4]  J. Pomeroy.  A Process-Based Model of Snow Drifting , 1989, Annals of Glaciology.

[5]  Wilfred M. Post,et al.  Soil carbon pools and world life zones , 1982, Nature.

[6]  P. Lafleur,et al.  Annual cycle of CO2 exchange at a bog peatland , 2001 .

[7]  N. Shurpali,et al.  Carbon dioxide exchange in a peatland ecosystem , 1995 .

[8]  Ü. Rannik,et al.  Gap filling strategies for defensible annual sums of net ecosystem exchange , 2001 .

[9]  W. Oechel,et al.  Spatial and temporal variations in hectare‐scale net CO2 flux, respiration and gross primary production of Arctic tundra ecosystems , 2000 .

[10]  M. Collins,et al.  Projections of future climate change , 2002 .

[11]  W. Oechel,et al.  The effects of climate charge on land-atmosphere feedbacks in arctic tundra regions. , 1994, Trends in ecology & evolution.

[12]  Walter C. Oechel,et al.  Recent change of Arctic tundra ecosystems from a net carbon dioxide sink to a source , 1993, Nature.

[13]  S. Wofsy,et al.  Biosphere/atmosphere CO2 exchange in tundra ecosystems - Community characteristics and relationships with multispectral surface reflectance , 1992 .

[14]  W. Oechel,et al.  Acclimation of ecosystem CO2 exchange in the Alaskan Arctic in response to decadal climate warming , 2000, Nature.

[15]  R. Leuninga,et al.  Source / sink distributions of heat , water vapour , carbon dioxide and methane in a rice canopy estimated using Lagrangian dispersion analysis , 2000 .

[16]  W. Oechel,et al.  Climate Change in Northern Latitudes: Alterations in Ecosystem Structure and Function and Effects on Carbon Sequestration , 1997 .

[17]  D. Paslier,et al.  Net Exchange of CO2 in a Mid-Latitude Forest , 1993, Science.

[18]  George L. Vourlitis,et al.  The effects of water table manipulation and elevated temperature on the net CO2 flux of wet sedge tundra ecosystems , 1998 .

[19]  H. Neumann,et al.  Carbon dioxide fluxes over a raised open bog at the Kinosheo Lake tower site during the Northern Wetlands Study (NOWES) , 1994 .

[20]  J. Kaimal,et al.  Another look at sonic thermometry , 1991 .

[21]  Seelye Martin,et al.  Variations in Surface Air Temperature Observations in the Arctic, 1979-97. , 2000 .

[22]  W. Oechel,et al.  Cold season CO2 emission from Arctic soils , 1997 .

[23]  W. Rouse,et al.  Interannual Variability in Net Ecosystem CO~2 Exchange at the Arctic Treeline , 2001 .

[24]  C. J. Moore.  Frequency response corrections for eddy correlation systems , 1986 .

[25]  Seelye Martin,et al.  Recent observations of a spring‐summer surface warming over the Arctic Ocean , 1997 .

[26]  J. William Munger,et al.  Measurements of carbon sequestration by long‐term eddy covariance: methods and a critical evaluation of accuracy , 1996 .

[27]  D. Jacob,et al.  Micrometeorological measurements of CH4 and CO2 exchange between the atmosphere and subarctic tundra , 1992 .

[28]  W. Oechel,et al.  Comparative CO2 exchange patterns in mosses from two tundra habitats at Barrow, Alaska , 1976 .

[29]  E. K. Webb,et al.  Correction of flux measurements for density effects due to heat and water vapour transfer , 1980 .

[30]  A. Lang,et al.  Effects of heat and water vapor transport on eddy covariance measurement of CO2 fluxes , 1982 .

[31]  W. Oechel,et al.  The Heat and Water Budgets in the Active Layer of the Arctic Tundra at Barrow, Alaska , 1996 .

[32]  R. Leuning,et al.  Source/sink distributions of heat, water vapour, carbon dioxide and methane in a rice canopy estimated using Lagrangian dispersion analysis , 2000 .

[33]  W. Oechel,et al.  Characteristics of energy and water budgets over wet sedge and tussock tundra ecosystems at North Slope in Alaska , 1998 .

[34]  J. Welker,et al.  Wintertime CO2 efflux from Arctic soils: Implications for annual carbon budgets , 1999 .

[35]  D. Solomon,et al.  The annual carbon dioxide cycle in a montane soil: Observations, modeling, and implications for weathering , 1987 .

[36]  Walter C. Oechel,et al.  New Estimates of Organic Matter Reserves and Net Primary Productivity of the North American Tundra Ecosystems , 1995 .

[37]  W. Oechel,et al.  FLUXNET: A New Tool to Study the Temporal and Spatial Variability of Ecosystem-Scale Carbon Dioxide, Water Vapor, and Energy Flux Densities , 2001 .

[38]  W. Oechel,et al.  Net CO2 Budget and Seasonal Variation of CO2 Fluxes at a Wet Sedge Tundra Ecosystem at Barrow, Alaska during the 2000 Growing Season , 2003 .

[39]  W. Rouse,et al.  Interannual Variability in Net Ecosystem CO2 Exchange at the Arctic Treeline , 2001 .

[40]  C. Lloyd.  The measurement and modelling of the carbon dioxide exchange at a high Arctic site in Svalbard , 2001 .

[41]  W. Rouse,et al.  Interannual variability of net ecosystem CO2 exchange at a subarctic fen , 2000 .

[42]  Effects of Micrometeorology on the CO2 Budget in Mid-summer over the Arctic Tundra at Prudhoe Bay, Alaska , 1997 .

[43]  R. Striegl,et al.  Winter fluxes of CO2 and CH4 from subalpine soils in Rocky Mountain National Park, Colorado , 1998 .

[44]  W. Oechel,et al.  Landscape-Scale CO 2 , H 2 O Vapour and Energy Flux of Moist-Wet Coastal Tundra Ecosystems over Two Growing Seasons , 1997 .

[45]  Ray Leuning,et al.  Carbon dioxide and methane fluxes from an intermittently flooded paddy field , 2000 .

[46]  W. Acevedo,et al.  Vegetation and a Landsat-derived land cover map of the Beechey Point quadrangle, Arctic coastal plain, Alaska , 1987 .

[47]  W. Rouse,et al.  Scaling net ecosystem CO2 exchange from the community to landscape‐level at a subarctic fen , 2000 .

[48]  W. Oechel,et al.  Change in Arctic CO2Flux Over Two Decades: Effects of Climate Change at Barrow, Alaska , 1995 .

[49]  Ray Leuning,et al.  The relative merits of open‐ and closed‐path analysers for measurement of eddy fluxes , 1996 .

[50]  J. Kelley,et al.  CO 2 Exchange over the Alaskan Arctic Tundra: Meteorological Assessment by an Aerodynamic Method , 1975 .

[51]  A. Miyata,et al.  Evaluation of Greenhouse Gas Fluxes over Agricultural and Natural Ecosystems by means of Micrometeorological Methods , 1997 .

[52]  C. B. Tanner,et al.  ANEMOCLINOMETER MEASUREMENTS OF REYNOLDS STRESS AND HEAT TRANSPORT IN THE ATMOSPHERIC SURFACE LAYER , 1969 .

[53]  G. Whiting.  CO2 exchange in the Hudson Bay lowlands: Community characteristics and multispectral reflectance properties , 1994 .

[54]  P. Lafleur.  Growing season energy and CO2 exchange at a subarctic boreal woodland , 1999 .