High-Frequency CO2 Monitoring of the Soil and Vegetation Gas Exchange with the Atmosphere to Assess the Local Carbon Balance of a Green Infrastructure Elementстатья
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Аннотация:Assessment of the local carbon balance of green infrastructure elements, relevant to the Environmental, Social, and Governance green agenda, is successfully solvable using state-of-the-art programmed loggers with NDIR CO2 detection in the air. The main idea underlying fully automated continuous monitoring of carbon gas exchange consists in a periodic pumping of the atmospheric air through closed chambers for soil and vegetation with subsequent exposure to assess the trends of carbon increase (CO2 emission) or sink (photosynthesis) using in-chamber CO2 loggers. This know-how has been implemented in the Serebryanyi Bor Experimental Forestry with the Institute of Forest Science, Russian Academy of Sciences, in Moscow in the case study of a blue spruce (Picea pungens Engelm.) plantation on cultivated soddy-podzolic loamy sandy soil (Cambisol). HT-401/5 (China) low-cost gas analyzers with a minute-wise recording have been used as CO2 loggers. The monitoring results demonstrate pronounced changes in the plant and soil components of carbon gas exchange, including repeated interannual variation in the local carbon balance from source to sink. The carbon emission losses from soil in the cold season amount to 8%; from vegetation, exceed 17% of the annual fluxes and do not cease even in severe frosts. The share of gross photosynthesis in evergreen plants exceeds 15% at the expense of periodic winter warm spells. Despite a positive annual integral estimate of about 100 g C/(m2 year), the dynamics of carbon balance follows a complex oscillatory pattern with nonlinear responses of carbon fluxes to temperature, which devalues the widespread estimate based on infrequent measurements of gas fluxes followed by temperature extrapolation.
