The growing season greenhouse gas balance of a continental tundra site in the Indigirka lowlands, NE Siberia
Publishing year: 2007
Document type: Journal article
Publisher: Copernicus Publications
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 degrees 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.
- Physical Geography
- ISSN: 1726-4189
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