Carbon dioxide balance of subarctic tundra from plot to regional scales

TY - JOUR

T1 - Carbon dioxide balance of subarctic tundra from plot to regional scales

AU - Marushchak, M.E.

AU - Kiepe, Isabell

AU - Biasi, C.

AU - Elsakov, V.

AU - Friborg, Thomas

AU - Johansson, Paul Torbjörn

AU - Søgaard, Henrik

AU - Virtanen, T.

AU - Martikainen, P.J.

N1 - CENPERMOA[2013]

PY - 2013

Y1 - 2013

N2 - We report here the carbon dioxide (CO2) budget of a 98.6 km2 subarctic tundra area in northeast European Russia based on measurements at two different scales and two independent upscaling approaches. Plot-scale measurements (chambers on terrestrial surfaces, gas gradient method and bubble collectors on lakes) were carried out from July 2007 to October 2008. The landscape-scale eddy covariance (EC) measurements covered the snow-free period of 2008. The annual net ecosystem exchange (NEE) of different land cover types ranged from −251 to 84 g C m-2. Leaf area index (LAI) was an excellent predictor of the spatial variability in gross photosynthesis (GP), NEE and ecosystem respiration (ER). The plot-scale CO2 fluxes were first scaled up to the EC source area and then to the whole study area using two data sets: a land cover classification and a LAI map, both based on field data and a 2.4 m pixel-sized QuickBird satellite image. The good agreement of the CO2 balances for the EC footprint based on the different measuring techniques (−105 to −81 g C m-2 vs. −79 g C m-2; growing season 2008) justified the integration of the plot-scale measurements over the larger area. The regional CO2 balance based on area-integrated plot-scale measurements was −41 or −79 g C m-2 yr-1 according to the two upscaling methods, the land cover classification and the LAI map, respectively. Due to the heterogeneity of tundra, the effect of climate change on CO2 uptake will vary strongly according to the land cover type and, moreover, likely changes in their relative coverage in the future will have great impact on the regional CO2 balance.

AB - We report here the carbon dioxide (CO2) budget of a 98.6 km2 subarctic tundra area in northeast European Russia based on measurements at two different scales and two independent upscaling approaches. Plot-scale measurements (chambers on terrestrial surfaces, gas gradient method and bubble collectors on lakes) were carried out from July 2007 to October 2008. The landscape-scale eddy covariance (EC) measurements covered the snow-free period of 2008. The annual net ecosystem exchange (NEE) of different land cover types ranged from −251 to 84 g C m-2. Leaf area index (LAI) was an excellent predictor of the spatial variability in gross photosynthesis (GP), NEE and ecosystem respiration (ER). The plot-scale CO2 fluxes were first scaled up to the EC source area and then to the whole study area using two data sets: a land cover classification and a LAI map, both based on field data and a 2.4 m pixel-sized QuickBird satellite image. The good agreement of the CO2 balances for the EC footprint based on the different measuring techniques (−105 to −81 g C m-2 vs. −79 g C m-2; growing season 2008) justified the integration of the plot-scale measurements over the larger area. The regional CO2 balance based on area-integrated plot-scale measurements was −41 or −79 g C m-2 yr-1 according to the two upscaling methods, the land cover classification and the LAI map, respectively. Due to the heterogeneity of tundra, the effect of climate change on CO2 uptake will vary strongly according to the land cover type and, moreover, likely changes in their relative coverage in the future will have great impact on the regional CO2 balance.

U2 - 10.5194/bg-10-437-2013

DO - 10.5194/bg-10-437-2013

M3 - Journal article

SN - 1726-4170

VL - 10

SP - 437

EP - 452

JO - Biogeosciences

JF - Biogeosciences

IS - 1

ER -