Aquatic Eddy covariance system for ecological and environmental research

水流向水生生物和海底沉积物输送溶解气体，如氧气、营养物质和化学信号，并向它们施加力。了解水生植物如何产生氧气，通过生物地球化学过程在沉积物中消耗氧气，或从地表水中输送氧气，是水生生态系统中至关重要的问题。此外，这种了解可以提供水生环境健康状况的指示，并有助于评价控制战略的有效性。申请资金用于购买涡流相关系统，以测量湖泊、河流和海洋水下栖息地的氧通量。在野外湍流条件下测量氧气通量的能力是对涉及实验室孵育或野外室的传统技术的重大改进，这些技术是侵入性的，不能应用于大空间尺度或复杂形状。涡动相关系统结合了专门设计的25 ？m直径氧传感器和快速响应放大器与快速响应声学多普勒测速仪。该系统的工作原理是在相同的采样体积内快速（例如，64赫兹）同时测量水速（三维）和溶解氧浓度。这些测量值可以分解为平均和波动分量，波动分量的乘积的平均值（u'c'）提供净湍流通量。就地测量氧通量的能力将代表我们在确定湖泊低氧水平的原因、濒危淡水贻贝物种的健康以及水生植被生产力方面的能力取得重大进展。这些信息还将导致水生环境的生物物理和数学模型的发展取得进展。

Water flow delivers dissolved gases such as oxygen, nutrients, and chemical signals to and from aquatic organisms and bottom sediments, as well as imparting forces on them.  An understanding of how oxygen is produced by aquatic plants, consumed in sediments by biogeochemical processes, or delivered from surface waters are vital and essential questions to ask about aquatic ecosystems. Moreover, such understanding can provide an indication of the health of aquatic environments and help to evaluate the effectiveness of control strategies.  Funds are requested for the purchases of an Eddy Covariance System to measure the oxygen flux in underwater habitats in lakes, rivers, and oceans.  The ability to measure the flux of oxygen under turbulent conditions in the field represents a significant improvement over traditional techniques involving laboratory incubations or field chambers, which are invasive and cannot be applied at large spatial scales or to complex shapes.  The eddy covariance system combines a specially designed 25 ?m diameter oxygen sensor and fast-response amplifier with a fast-response acoustic Doppler velocimeter.  The system works by making rapid (e.g., 64 Hz) and simultaneous measurements of water velocity (in three dimensions) and dissolved oxygen concentration in the same sampling volume.  These measurements can be decomposed into average and fluctuating components and the average of the product of the fluctuation components (u'c') provides the net turbulent flux.  The ability to measure oxygen flux in situ will represents a significant advance in our ability to determine the causes of low oxygen levels in lakes, the health of endangered freshwater mussel species, as well as the productivity of aquatic vegetation. This information will also lead to advances in the development of bio-physical and mathematical models of aquatic environments.