Carbon Dioxide and Water Exchange Between Spruce and Atmosphere in the Spring-Summer in Different Weather Conditions
S. V. ZAGIROVA, O. A. MIKHAILOV, V. V. ELSAKOV
Institute of Biology of Komi Scientific Centre, Ural Branch of RAS, 167982, Syktyvkar, Kommunisticheskaya str., 28
Keywords: еловое насаждение, атмосфера, средняя тайга, нетто-обмен диоксида углерода, гросс-фотосинтез, экосистемное дыхание, эвапотранспирация, метод микровихревых пульсаций, spruce forest ecosystem, atmosphere, middle taiga, ecosystem net exchange of carbon dioxide, gross photosynthesis, ecosystem respiration, evapotranspiration, eddy covariance measurements
Abstract
The results of eddy covariance measurements of carbon dioxide and water fluxes above spruce forest in the middle taiga subzone from April to August in 2013 and 2016 are presented. The ecosystem of spruce forest turned from source to sink of CO2 at average daily air temperatures below zero in late March and early April, in 2016 it was two weeks earlier than in 2013. The maximum net ecosystem exchange (NEE) of CO2 was recorded at the end of June and the beginning of July. In 2016 the average daily NEE of spruce forest decreased at high air temperature and a low amount of precipitation at the beginning of the growing season, and turning from the sink of CO2 to the source was observed in early August. Net exchange of CO2 between spruce and the atmosphere from April to August in 2013 reached -327 g C/m2, and in 2016 -174 g C/m2. Seasonal evapotranspiration of spruce forest in those years was 239-247 mm / m2, and the average value of the water use efficiency (WUE) for photosynthesis in the season was 2.3-3.3 g C/kg H2O. WUE was relatively constant during the growing season as a result of a close relationship between the exchange of CO2 and water, the main processes ensuring the production of organic matter in the spruce forest ecosystem.
|
