Technical Note: Semi-rigid chambers for methane gas flux measurements on tree stems
Technical Note: Semi-rigid chambers for methane gas flux measurements on tree stems
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DOI：
10.5194/bg-13-1197-2016
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发表时间：
2016-01-01
期刊：
影响因子：
4.9
通讯作者：
Gauci, Vincent
中科院分区：
文献类型：
--
作者：
Siegenthaler, Andy;Welch, Bertie;Gauci, Vincent
在广泛的生态系统中，测量树干的甲烷（CH 4）排放量，以确定它们对总生态系统通量的贡献越来越受到关注。迄今为止，树木CH 4通量通常使用刚性封闭室（静态或动态）进行测量，这通常会带来挑战，因为这些体积庞大，并且将CH 4通量的测量限制在非常窄的树干尺寸和形状范围内。为了克服这些挑战，我们的目标是设计和测试新的半刚性杆通量室（或套筒）。我们比较了新的半刚性室的甲烷渗透性与传统的刚性室的方法，在实验室和现场，连续流动或注射器注射。我们发现，半刚性腔室具有降低的气体渗透性和最佳的杆气体交换表面与总腔室体积比（S-c / V-tot），从而允许更好的顶部空间混合，特别是当以动态模式连接到连续流动气体分析仪时。半刚性套管可以很容易地以多种尺寸构造和运输，非常轻，建造成本低，部署速度快。这使得它们非常适合用于接入物流复杂的偏远生态系统。
There is increasing interest in the measurement of methane (CH4) emissions from tree stems in a wide range of ecosystems so as to determine how they contribute to the total ecosystem flux. To date, tree CH4 fluxes are commonly measured using rigid closed chambers (static or dynamic), which often pose challenges as these are bulky and limit measurement of CH4 fluxes to only a very narrow range of tree stem sizes and shapes. To overcome these challenges we aimed to design and test new semi-rigid stem-flux chambers (or sleeves). We compared the CH4 permeability of the new semi-rigid chambers with that of the traditional rigid chamber approach, in the laboratory and in the field, with continuous flow or syringe injections. We found that the semi-rigid chambers had reduced gas permeability and optimal stem gas exchange surface to total chamber volume ratio (S-c / V-tot) allowing better headspace mixing, especially when connected in a dynamic mode to a continuous flow gas analyser. Semirigid sleeves can easily be constructed and transported in multiple sizes, are extremely light, cheap to build and fast to deploy. This makes them ideal for use in remote ecosystems where access logistics is complicated.