Oxygen dynamics in large reservoirs: A new framework for understanding the formation of metalimnetic oxygen minima

溶解氧(DO)是湖泊、水库水质管理中的一个重要指标。它对这些Lentium生态系统的生态系统功能至关重要。太低的浓度(缺氧)限制了饮用水和其他用途的水的可用性。更多的健康问题是由缺氧水引起的。最后也是同样重要的一点，水处理变得昂贵。因此，我们的淡水水体的健康和可持续运作是最符合公众利益的。因此，我们建议中德两国从事水研究的领先研究机构的科学家开展合作，这些研究机构以在国内外解决新颖和具有挑战性的环境问题而闻名。数值模拟工具以及现场实验和测量都将在现有设备的前沿进行操作。通过这次合作，我们期待着就现有的水问题达成相互理解，就现代现场设备和在数值模拟中实施这些数据进行密集的交流，最终更敏感地了解有关水问题和水库管理的新知识如何在另一个国家付诸实践。水是一个核心的健康问题，公众从改善水质中受益。氧气对有机污染、富营养化或气候变化等环境应激源反应高度敏感。由于生态、生物地球化学和物理过程的复杂相互作用，对其动态的预测是一项具有挑战性的任务。虽然亚磁DO的动力学已经得到了深入的研究，因此可以很准确地预测许多目的，但对金属离子中DO的动力学(即温暖的上表层和冷的深层底层之间的层)的了解还远远不够。金属磁最低氧(MOM)是一种在淡水和海洋系统中已知的现象，它是由高需氧量和低垂直交换共同引起的。金属中DO需求增加的原因受到推测，并涉及其他机制，如浮游生物呼吸、进口异地物质、混浊限制的呼吸或沉积物质的分解。这项建议的目的是在德国和中国的水库(拉普博德水库和潘家口水库)实施高分辨率的DO监测，并进行现场和实验室实验，以检验关于DO消耗驱动因素的各种假说。野外和实验室实验以及高分辨率监测研究的结果通过嵌入一维和三维水动力-生物地球化学耦合湖泊模型的数学过程描述来概念化。开发的模型工具在基于开放源代码的模型框架中提供给科学界。

Dissolved oxygen (DO) is a key quantity in water quality management of lakes and reservoirs. It is essential for the ecosystem functioning of these lentic ecosystems. Too low concentrations (anoxia) limit the usability of water for drinking and other purposes. Additional health issues arise from anoxic waters. Last and not least, water treatment becomes expensive. Hence, a healthy and sustainable operation of our freshwater bodies is of prime public interest. Therefore, we propose cooperation between scientists of a leading Chinese and German research institutions involved in water research with a reputation for approaching novel and challenging environmental concerns inside and outside their own countries. Both, numerical simulation tools as well as field experiments & measurements will be operated at the forefront of currently available equipment. From this collaboration, we anticipate a mutual understanding for existing water issues, an intensive exchange about modern field equipment and the implementation of such data in numerical simulations and finally more sensibility of how new knowledge about water issues and reservoir management are put into practice in the other country. Water is a central health issue and the public profits from improved water quality. Oxygen reacts highly sensitive against environmental stressors like organic pollution, eutrophication or climate change. The prediction of its dynamics is a challenging task due to the complex interaction of ecological, biogeochemical, and physical processes. While the dynamics of hypolimnetic DO have been studied intensively and, as a consequence, can be predicted with sufficient accuracy for many purposes, the dynamics of DO in the metalimnion (i.e. the layer between the warm upper epilimnion and the cold, deep hypolimnion) have been understood far less. Metalimnetic oxygen minima (MOM), a phenomenon known from freshwater and marine systems, arise from a combination of high oxygen demand and low vertical exchange. The causal factors of the increased DO demand within the metalimnion are subjected to speculation and involve alternative mechanisms like plankton respiration, imported allochthonous material, turbidity-bound respiration or the breakdown of sedimenting material. The aim of this proposal is the implementation of high-resolution DO-monitoring in German and Chinese Reservoirs (Rappbode Reservoir and Panjiakou Reservoir) together with field and laboratory experiments for testing various hypotheses about the drivers of DO consumption. Results of the field and lab experiments as well as high-resolution monitoring studies are conceptualized by mathematical process descriptions that are embedded in 1D and 3D coupled hydrodynamic-biogeochemical lake models. The developed model tools are provided to the scientific community in model frameworks based on open source codes.