Theory, hypothesis and application advance in chamber-based technology and methods for flux measurement

doi:10.17521/cjpe.2019.0201

Abstract

Abstract:

The exchange flux of greenhouse gases, such as carbon (CO₂, CH₄), nitrogen (N₂O) and water vapour (H₂O), is the core of material cycle in the ecosystem and the bond of interaction among geosphere, biosphere and atmosphere. The development of stable isotope infrared spectroscopy and mass spectrometry technology and methods makes it possible to measure carbon stable isotopic composition (δ ¹³C) and oxygen stable isotopic composition (δ ¹⁸O)(CO₂), δ ¹³C (CH₄), nitrogen stable isotope composition (δ ¹⁵N) and δ ¹⁸O (N₂O), hydrogen stable isotopic composition (δD) and δ ¹⁸O (H₂O), which realizes the observation of greenhouse gas and its isotope flux at the soil, plant and ecosystem scales in combined with chamber-based technology and methods for flux measurement. Taking the chamber-based technology and methods for CO₂ and its δ ¹³C flux measurement as an example, this review which summarizes the basic principle and classification of the flux measurement system, expounds the theory requirements and assumptions of system design, summarizes the application advance and problems of chamber-based technology and methods for flux measurement in soil, plants (leaf, stem, and root) and ecosystem scales from the field to indoor, and prospects the importance of precision and accuracy of gas analysis and measurement data and the representativeness of measurement data in chamber-based flux measurement.

Key words: greenhouse gas, stable isotope, precision, accuracy, representative

WEI Jie, CHEN Chang-Hua, WANG Jing-Yuan, WEN Xue-Fa. Theory, hypothesis and application advance in chamber-based technology and methods for flux measurement[J]. Chin J Plant Ecol, 2020, 44(4): 318-329.

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https://www.plant-ecology.com/EN/Y2020/V44/I4/318

Figures/Tables 2

Fig. 1 System characteristics and CO2 concentration change inside of chamber at non-steady-state (A, B) and steady-state (C, D). Cc and Ca represent the CO2 concentration inside and outside of the chamber, respectively; Pc and Pa represent the atmosphere pressure inside and outside of the chamber, respectively; Tc and Wc represent the air temperature and moisture inside the chamber, respectively.

Fig. 2 Diagram on cooperative observation system of the CO2 carbon stable isotope composition (δ13C) flux of soil and plant (A) and observation system of the CO2 δ13C flux of canopy and ecosystem (B). In A, we only take leaf and soil chambers as an example to show the flow diagram of gas system (stem and root chambers same as leaf chamber).

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