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Abstract:
Direct measurements of CO2 fluxes by the eddy covariance method have demonstrated that the
examined middletaiga pine forest, raised bog, true steppe, and southern tundra along the Yenisei meridian
(~90° E) are carbon sinks of different capacities according to annual output. The tundra acts as a carbon sink
starting from June; forest and bog, from May; and steppe, from the end of April. In transitional seasons and
winter, the ecosystems are a weak source of carbon; this commences from September in the tundra, from
October in the forest and bog, and from November in the steppe. The photosynthetic productivity of forest
and steppe ecosystems, amounting to 480–530 g C/(m2 year), exceeds by 2–2.5 times that of bogs and tun
dras, 200–220 g C/(m2 year). The relationships between the heat balance structure and CO2 exchange are
shown. Possible feedback of carbon exchange between the ecosystems and atmosphere as a result of climate
warming in the region are assessed.
