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Tundra landscape heterogeneity, not interannual variability, controls the decadal regional carbon balance in the Western Russian Arctic

Treat, Claire C.; Marushchak, Maija E.; Voigt, Carolina; Zhang, Yu; Tan, Zeli; Zhuang, Qianlai; Virtanen, Tarmo A.; Räsänen, Aleksi; Biasi, Christina and Hugelius, Gustaf, et al. (2018) In Global Change Biology 24(11). p.5188-5204
Abstract

Across the Arctic, the net ecosystem carbon (C) balance of tundra ecosystems is highly uncertain due to substantial temporal variability of C fluxes and to landscape heterogeneity. We modeled both carbon dioxide (CO2) and methane (CH4) fluxes for the dominant land cover types in a ~100-km2 sub-Arctic tundra region in northeast European Russia for the period of 2006–2015 using process-based biogeochemical models. Modeled net annual CO2 fluxes ranged from −300 g C m−2 year−1 [net uptake] in a willow fen to 3 g C m−2 year−1 [net source] in dry lichen tundra. Modeled annual CH4 emissions ranged from −0.2 to 22.3 g C m−2... (More)

Across the Arctic, the net ecosystem carbon (C) balance of tundra ecosystems is highly uncertain due to substantial temporal variability of C fluxes and to landscape heterogeneity. We modeled both carbon dioxide (CO2) and methane (CH4) fluxes for the dominant land cover types in a ~100-km2 sub-Arctic tundra region in northeast European Russia for the period of 2006–2015 using process-based biogeochemical models. Modeled net annual CO2 fluxes ranged from −300 g C m−2 year−1 [net uptake] in a willow fen to 3 g C m−2 year−1 [net source] in dry lichen tundra. Modeled annual CH4 emissions ranged from −0.2 to 22.3 g C m−2 year−1 at a peat plateau site and a willow fen site, respectively. Interannual variability over the decade was relatively small (20%–25%) in comparison with variability among the land cover types (150%). Using high-resolution land cover classification, the region was a net sink of atmospheric CO2 across most land cover types but a net source of CH4 to the atmosphere due to high emissions from permafrost-free fens. Using a lower resolution for land cover classification resulted in a 20%–65% underestimation of regional CH4 flux relative to high-resolution classification and smaller (10%) overestimation of regional CO2 uptake due to the underestimation of wetland area by 60%. The relative fraction of uplands versus wetlands was key to determining the net regional C balance at this and other Arctic tundra sites because wetlands were hot spots for C cycling in Arctic tundra ecosystems.

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@article{044df730-3a5f-4641-a15e-fce16a4f0bc0,
  abstract     = {<p>Across the Arctic, the net ecosystem carbon (C) balance of tundra ecosystems is highly uncertain due to substantial temporal variability of C fluxes and to landscape heterogeneity. We modeled both carbon dioxide (CO<sub>2</sub>) and methane (CH<sub>4</sub>) fluxes for the dominant land cover types in a ~100-km<sup>2</sup> sub-Arctic tundra region in northeast European Russia for the period of 2006–2015 using process-based biogeochemical models. Modeled net annual CO<sub>2</sub> fluxes ranged from −300 g C m<sup>−2</sup> year<sup>−1</sup> [net uptake] in a willow fen to 3 g C m<sup>−2</sup> year<sup>−1</sup> [net source] in dry lichen tundra. Modeled annual CH<sub>4</sub> emissions ranged from −0.2 to 22.3 g C m<sup>−2</sup> year<sup>−1</sup> at a peat plateau site and a willow fen site, respectively. Interannual variability over the decade was relatively small (20%–25%) in comparison with variability among the land cover types (150%). Using high-resolution land cover classification, the region was a net sink of atmospheric CO<sub>2</sub> across most land cover types but a net source of CH<sub>4</sub> to the atmosphere due to high emissions from permafrost-free fens. Using a lower resolution for land cover classification resulted in a 20%–65% underestimation of regional CH<sub>4</sub> flux relative to high-resolution classification and smaller (10%) overestimation of regional CO<sub>2</sub> uptake due to the underestimation of wetland area by 60%. The relative fraction of uplands versus wetlands was key to determining the net regional C balance at this and other Arctic tundra sites because wetlands were hot spots for C cycling in Arctic tundra ecosystems.</p>},
  author       = {Treat, Claire C. and Marushchak, Maija E. and Voigt, Carolina and Zhang, Yu and Tan, Zeli and Zhuang, Qianlai and Virtanen, Tarmo A. and Räsänen, Aleksi and Biasi, Christina and Hugelius, Gustaf and Kaverin, Dmitry and Miller, Paul A. and Stendel, Martin and Romanovsky, Vladimir and Rivkin, Felix and Martikainen, Pertti J. and Shurpali, Narasinha J.},
  issn         = {1354-1013},
  keyword      = {ecosystem modeling,methane,net ecosystem CO exchange,peatland,permafrost,regional carbon balance,Russia,Tundra},
  language     = {eng},
  number       = {11},
  pages        = {5188--5204},
  publisher    = {Wiley-Blackwell},
  series       = {Global Change Biology},
  title        = {Tundra landscape heterogeneity, not interannual variability, controls the decadal regional carbon balance in the Western Russian Arctic},
  url          = {http://dx.doi.org/10.1111/gcb.14421},
  volume       = {24},
  year         = {2018},
}