Three dimensional hydrodynamic and ecological models for water quality problems in Lake Erie

美国和加拿大已经花费了数十亿美元来控制伊利湖的营养物质负荷，消除伊利湖中央盆地的深水缺氧(低氧水平)是一个重要目标。尽管近海湖水的叶绿素和磷水平有所改善，但近年来缺氧情况似乎有所恶化。造成这种情况的原因有几种假设，包括气候条件的变化，河流输入的营养物质的变化，以及20世纪80年代入侵伊利湖的非本地贻贝的影响。深水缺氧发生在湖的较低层，称为Hypolimnion，位于随深度快速变化的温度快速变化的薄层Metalimnion之下。金属离子是氧气向下流动的屏障。近年来，人们认识到，打破金属离子中的内波是这种向下流动的重要机制。这是湖泊中的物理过程对生物和化学过程产生影响的几种方式之一。在这项研究中，数据将被用来验证湖泊尺度的水动力-生物地球化学数值模型，然后该模型将被用来证明当前假设的含义，并探索未来气候变化情景的可能含义。为了阐明破裂内波在温跃层中的作用，将进行一个现场计划，以获得高时间和空间分辨率的数据。这将是伊利湖第一次进行这样的研究。将进行物理、化学和生物测量，以便在各种过程之间建立联系，并确定它们在低氧水形成中的作用。将进行湖泊规模和高分辨率的数值模拟，以提供这些重要过程的更全面的图景。这项研究将全面了解大小尺度过程在深水缺氧形成中的作用，并为这一重要湖泊的未来管理提供有用的工具，这些工具也可以应用于其他湖泊。

Billions of dollars have been spent on the control of nutrient loading to Lake Erie in the U.S. and Canada with the elimination of deep water hypoxia (low oxygen levels) in the central basin of the lake an important goal. In spite of improvements in chlorophyll and phosphorus levels in offshore lake waters, hypoxia appears to have worsened in recent years. There are several hypotheses for the cause of this, including changing climatic conditions, changes in nutrient input from rivers, and the effects of non-native mussels which invaded Lake Erie in the 1980s.Deep water hypoxia occurs in the lower layer of the lake, called the hypolimnion, which lies beneath a thin layer of rapid temperature change with depth called the metalimnion. The metalimnion represents a barrier for the downward flux of oxygen. In recent years it has become appreciated that breaking internal waves in the metalimnion are an important mechanism for this downward flux. This is one of several ways in which physical processes in the lake have an impact on biological and chemical processes.In this research data will be used to validate a lake-scale hydrodynamic-biogeochemical numerical model which will then be used to demonstrate the implications of current hypotheses and to explore the possible implications of future climate change scenarios. In order to elucidate the role of breaking internal waves in the thermocline a field program will be conducted to obtain data with high temporal and spatial resolution. This will be the first such study in Lake Erie. Physical, chemical and biological measurements will be made enabling links between various processes to be made and to establish their role in the formation of hypoxic water. Lake-scale and high-resolution numerical simulations will be undertaken to provide a fuller picture of these important processes. This research will result in a synthesized picture of the role of large and small scale processes in the formation of deep water hypoxia and provide useful tools for the future management of this important lake, tools which can also be applied to other lakes.