Developing and Testing a Robust and Reliable Field Method for In-Situ Analysis of Dissolved Gases in Streams

可靠地测量主要气体和微量气体的溶解浓度，可以评估水生系统中水通量和生化周转的动态。我们希望建立一种稳健可靠的方法，用于现场气体示踪剂测量和河流中连续气体监测，使用能够以准连续方式测量溶解气体浓度的气体平衡膜入口质谱仪。我们进一步想开发一种一致的方法来确定再速率系数的溪流使用上述现场气体分析仪，以确定溶解气体示踪剂的损失和溶解氧的浓度在溪流和低循环区。为此，我们将使仪器适应溪流中的气体示踪剂测试，并测试不同气体示踪剂化合物（即惰性气体和丙烷）的适用性，在靠近t<s:1>宾根的溪流中进行和评估气体示踪剂测试，并使该方法适应小水量，使其与河床中的微型压力表一起应用可行。注入气体示踪剂和溶解氧的可靠测量将有助于解开溪流中气体交换、光合作用和溶解氧有氧代谢的相互作用过程。

Reliably measuring dissolved concentrations of major and trace gases enables assessing the dynamics of water fluxes and biochemical turnover in aquatic systems. We want to establish a robust and reliable method for on-site gas-tracer measurements and continuous gas monitoring in rivers using a gas-equilibrium membrane inlet mass spectrometer capable of measuring concentrations of dissolved gases in a quasi-continuous manner. We further want to develop a consistent method for the determination of reaeration rate coefficients in streams using the mentioned field gas analyzer to determine the loss of dissolved gas tracers and the concentration of dissolved oxygen in streams and the hyporheic zone. Towards this ends we will adapt the instrument for gas-tracer tests in streams and test the applicability of different gas tracer compounds (namely noble gases and propane), conduct and evaluate gas-tracer tests in streams close to Tübingen, and adapt the method for small water volumes to make the application together with mini piezometers in the streambed feasible. The reliable measurements of injected gas tracers and dissolved oxygen will help to disentangle the interacting processes of gas-exchange, photosynthesis, and aerobic metabolism of dissolved oxygen in streams.