Abstract Understanding transport and biogeochemical turnover processes of solutes in riverine systems is vital in order to preserve aquatic and terrestrial ecosystem health. The hyporheic zone is the well-studied interface between stream water and underlying aquifer. It acts as a hydrodynamically driven bioreactor, i.e. its reactivity is strongly controlled by its dynamic subsurface flow patterns. Fibre optic sensing techniques and, in particular, fluorescence spectroscopy using a suite of fluorescent substances can provide unique information about physical, chemical, and biological processes occurring in the hyporheic zone. However, current devices for in situ fluorescence measurements in sediment pore water are insufficient in measurement reproducibility due to significant shortcomings of their mechanical design. Therefore, a novel design concept for a robust fluorescence sensor system performing reproducible real-time in situ fluorescence measurements in sediment pore water was developed. The holistic design concept includes the mechanical protection of the fibre optic tip, constant optical properties of the measurement environment, significantly reduced turbidity effects, and de-risk the formation of interfering gas bubbles. The study demonstrates the robustness and suitability of the prototype for in situ fluorescence measurements in laboratory and field using the fluorescence dye uranine. The presented proof of concept for the fluorescence sensor system may provide a fundamental basis for a sensor system performing any fluorescence spectroscopy analysis in sediment pore water in real time.

中文翻译：

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沉积物孔隙水中荧光示踪剂原位测量的新型装置

摘要 了解河流系统中溶质的运输和生物地球化学周转过程对于保护水生和陆地生态系统健康至关重要。潜流带是经过充分研究的河流水和下伏含水层之间的界面。它充当流体动力学驱动的生物反应器，即其反应性受到其动态地下流动模式的强烈控制。光纤传感技术，特别是使用一组荧光物质的荧光光谱，可以提供关于发生在低流带中的物理、化学和生物过程的独特信息。然而，目前用于沉积物孔隙水中原位荧光测量的装置由于其机械设计的显着缺陷而在测量再现性方面不足。所以，开发了一种新颖的设计概念，用于在沉积物孔隙水中执行可重现的实时原位荧光测量的稳健荧光传感器系统。整体设计理念包括光纤尖端的机械保护、测量环境的恒定光学特性、显着降低的浊度影响以及消除干扰气泡形成的风险。该研究证明了原型在实验室和现场使​​用荧光染料铀进行原位荧光测量的稳健性和适用性。所提出的荧光传感器系统的概念证明可以为传感器系统在沉积物孔隙水中实时执行任何荧光光谱分析提供基本基础。