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

• Published in: Global Change Biology
• Main Authors: Treat, CC, Marushchak, ME, Voigt, C, Zhang, Y, Tan, Z, Zhuang, Q, Virtanen, TA, Räsänen, A, Biasi, C, Hugelius, G, Kaverin, D, Miller, PA, Stendel, M, Romanovsky, V, Rivkin, F, Martikainen, PJ, Shurpali, NJ
• Other Authors: Ympäristö- ja biotieteiden laitos / Toiminta
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Wiley 2018
• Subjects: tundra; Russia; regional carbon balance; net ecosystem CO2 exchange; methane; 37 ecosystem modeling; permafrost; peatland; Arctic; Peat; Peat plateau; Tundra
• Online Access: https://erepo.uef.fi/handle/123456789/6953

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. final draft peerReviewed