Methane (CH₄) emissions from aquatic ecosystems require accurate monitoring in the context of climate change. Among the several methods for CH₄ flux measurement, open dynamic chambers (ODC) are a reliable option. This method consists of a floating chamber through which a carrier gas is constantly flowing, providing accurate flux measurement with high temporal resolution. However, this method requires expensive and heavy CH₄ analyzers with high sensitivity, as well as a carrier gas system that comprises a gas cylinder and a gas flow controller, among other components. This system involves significant weight and cost challenges, limiting method implementation in certain settings and hindering its wider adoption. To address these limitations, we developed a simplified ODC configuration using atmospheric air as the carrier gas and a light and relatively less expensive detector. We applied this method to a 450-ha urban lake with CH₄ emissions ranging from moderate diffusive to high ebullitive fluxes. Concurrent measurements using a high-sensitivity CH₄ analyzer allowed us to compare the accuracy of the simplified ODC method and to assess its advantages and disadvantages. Results show that our method provides accurate CH₄ flux measurements with a spatial resolution comparable to high-sensitivity analyzers. This offers a more cost-effective, straightforward, and lightweight alternative to high-sensitivity detectors and carrier gas systems, simplifying ODC deployment in aquatic ecosystems.

中文翻译：

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一种简单且低成本的开放式动态室，用于多功能测定水生表面的甲烷排放

在气候变化的背景下，需要准确监测水生生态系统的甲烷（CH _{4 ）排放。在 CH 4}通量测量的多种方法中，开放式动态室 (ODC) 是一种可靠的选择。该方法由一个载气不断流过的浮室组成，提供具有高时间分辨率的精确通量测量。然而，该方法需要昂贵且笨重的高灵敏度CH ₄分析仪，以及包括气瓶和气体流量控制器等部件的载气系统。该系统涉及重大的重量和成本挑战，限制了方法在某些环境下的实施并阻碍了其更广泛的采用。为了解决这些限制，我们开发了一种简化的 ODC 配置，使用大气作为载气和轻型且相对便宜的检测器。我们将此方法应用于一个 450 公顷的城市湖泊，其 CH ₄排放量范围从中等扩散通量到高沸腾通量。使用高灵敏度 CH ₄分析仪进行并行测量使我们能够比较简化 ODC 方法的准确性并评估其优点和缺点。结果表明，我们的方法提供了准确的 CH ₄通量测量，其空间分辨率与高灵敏度分析仪相当。这为高灵敏度探测器和载气系统提供了一种更具成本效益、简单且轻便的替代方案，简化了 ODC 在水生生态系统中的部署。