Development of an In-situ Dissolved Oxygen Sensing Network to Map the Temporal Dynamics of the Oxic/Anoxic Interface in Ecosystems

环境传感器网络是地球科学研究中的一种新兴工具，它将使科学家能够研究气候对完整生态系统的影响。 传感器网络必须能够进行涵盖数分钟或数小时的快速波动以及季节性和年度过程的测量。所需要的是能够提供来自整个生态系统的24小时/天、365天/年的现场数据的仪器。溶解氧浓度是环境中的一个关键变量，它影响生态系统的可居住性、碳循环和固存，沿着陆地和水生系统中的基本生物化学反应。科学家需要追踪水中好氧（含氧）和缺氧（缺氧）区域之间的边界。 这一边界如何随时间演变，可以反映全球或当地的环境变化，包括不寻常的事件，如在墨西哥湾或伊利湖形成死亡区，从生物修复现场浸出有毒金属或在饮用水供应威尔斯井挥发性有机化合物的运输。目前用于监测氧气浓度的技术不具备在生态系统一级提供长期所需数据的能力。该项目将开发一种新的氧传感器系统，能够自主远程监测好氧/缺氧界面。除了仪器开发外，该项目还将为关注水质的当地利益攸关方建立一个社区资源。目的是以公众可以获得的方式提供关于现有技术的信息。项目科学家将与密歇根州湖泊和溪流协会合作，该协会的成员包括流域/水资源管理社区和湖泊协会。这些互动将导致创建一个网站，暂定标题？我的水？是项计划的智慧价值在于综合纳米尺度的金属卤化物团簇电子物理学、化学测量技术、光学和电子器件设计以及光纤工程，以开发一个实时氧气传感系统。密歇根州立大学开发的磷光MoCl发光体具有独特的光化学特性，可以在水生系统和部分饱和的多孔沉积物中使用相同的设备进行数月至数年的原位氧气监测。垂直分辨光纤氧气探头，毫米级分辨率，将部署24/7，而无需重新校准，尽管存在常见的污染物。利用目前的技术，这样的系统只能以高昂的货币成本部署，同时需要大量的劳动力来操作;这种新的光学氧传感器探头将规避这些现有技术的限制。

Environmental sensor networks are an emerging tool in earth science research that will enable scientists to study the effects of climate on a complete ecosystem. The sensor network must be capable of making measurements that cover rapid fluctuations spanning minutes or hours as well as seasonal and annual processes. What is needed is instrumentation that can provide in-situ data from an entire ecosystem 24 hours/day, 365 days/year. Dissolved oxygen concentration is a key variable in the environment that influences the habitability of ecosystems, carbon cycling and sequestration, along with the basic bio-chemical reactions in both terrestrial and aquatic systems. Scientists need to track the boundary between the oxic (oxygen containing) and anoxic (depleted of oxygen) regions in water. How this boundary evolves in time can reflect global or local environmental changes including unusual events such as formation of dead zones in the Gulf of Mexico or Lake Erie, leaching of toxic metals from bioremediation sites or the transport of volatile organic compounds in drinking water supply wells. Current technologies for monitoring oxygen concentration do not have the capability to provide the required data over extended periods at the ecosystem level. This project will develop a new oxygen sensor system capable of autonomous, remote monitoring of the oxic/anoxic interface. In addition to instrumentation development, the project will establish a community resource for local stakeholders concerned about water quality. The objective is to provide information on available technologies in a manner that is accessible to the general public. The project scientists will work with the Michigan Lakes and Streams Association, whose members include watershed/water resource management communities and lake associations. These interactions will lead to the creation of a website, tentatively titled ?MyMIwater?, on water quality monitoring methods accessible to the citizen environmentalist.The intellectual merit of this project lies in the synthesis of nano-scale metal-halide cluster photophysics, chemical measurement techniques, optical and electronic device design and fiber optic engineering to develop a real-time oxygen sensing system. The unique photochemistry of the phosphorescent MoCl luminophores developed at Michigan State University enables in-situ oxygen monitoring for months to years with the same device in both aquatic systems and partially saturated porous sediment. Vertically resolved fiber optic oxygen probes, with mm scale resolution, will be deployed 24/7 without need for recalibration despite the presence of common contaminants. With current technologies such a system could only be deployed at prohibitive monetary cost while requiring significant labor to operate; this new optical oxygen sensor probe will circumvents the limitations of these existing techniques.