The growing season greenhouse gas balance of a continental tundra site in the Indigirka lowlands, NE Siberia

• Published in: Biogeosciences
• Main Authors: Molen, M. K., Huissteden, J., Parmentier, F. J. W., Petrescu, A. M. R., Dolman, A. J., Maximov, T. C., Kononov, A. V., Karsanaev, S. V., Suzdalov, D. A.
• Format: Text
• Language: English
• Published: 2018
• Subjects: Indigirka; Tundra; Siberia
• Online Access: https://doi.org/10.5194/bg-4-985-2007; https://www.biogeosciences.net/4/985/2007/

Carbon dioxide and methane fluxes were measured at a tundra site near Chokurdakh, in the lowlands of the Indigirka river in north-east Siberia. This site is one of the few stations on Russian tundra and it is different from most other tundra flux stations in its continentality. A suite of methods was applied to determine the fluxes of NEE, GPP, R eco and methane, including eddy covariance, chambers and leaf cuvettes. Net carbon dioxide fluxes were high compared with other tundra sites, with NEE=−92 g C m −2 yr −1 , which is composed of an R eco =+141 g C m −2 yr −1 and GPP=−232 g C m −2 yr −1 . This large carbon dioxide sink may be explained by the continental climate, that is reflected in low winter soil temperatures (−14°C), reducing the respiration rates, and short, relatively warm summers, stimulating high photosynthesis rates. Interannual variability in GPP was dominated by the frequency of light limitation ( R g <200 W m −2 ), whereas R eco depends most directly on soil temperature and time in the growing season, which serves as a proxy of the combined effects of active layer depth, leaf area index, soil moisture and substrate availability. The methane flux, in units of global warming potential, was +28 g C-CO 2 e m −2 yr −1 , so that the greenhouse gas balance was −64 g C-CO 2 e m −2 yr −1 . Methane fluxes depended only slightly on soil temperature and were highly sensitive to hydrological conditions and vegetation composition.