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Coupled physical and biogeochemical dynamics in shallow aquatic systems: Observations, theory and models.

机译：浅水系统中的物理和生物地球化学动力学耦合：观测，理论和模型。

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摘要

Shallow (3m) water bodies are ubiquitous, receive considerable loads of carbon and nutrients and their internal processes can exert significant control on the downstream biogeochemical fluxes. These shallow systems are characterized by tight coupling between biogeochemical and physical dynamics. This work investigates these coupled dynamics through observation, theory and model results. Observations were made in Mirror Lake (mean depth=0.7m) at the University of Connecticut, using a novel system for high temporal and spatial resolution sampling with real-time data processing and display.; Diurnal stratification/destratification dynamics affect biogeochemical cycles by controlling the rates of vertical transport and mixing. Geochemically significant daytime stratification can be predicted with a single parameter based on the product of water depth and the diffuse attenuation coefficient of visible light. Nighttime destratification is controlled by surface cooling, particularly under light winds. Using the potential energy anomaly as an integrated measure of water column stratification, diurnal stratification/destratification dynamics can be modeled as a linear function of the heat fluxes across the air-water interface, water depth and the diffuse light attenuation coefficient.; Diurnal stratification/destratification dynamics can be quantified by the vertical eddy diffusivity (Kz). Using the Princeton Ocean Model (POM), a three-dimensional ocean circulation model adapted to shallow inland water bodies, it is shown that Kz varies over four orders of magnitude in response to diurnal stratification dynamics, and that transitions from low Kz (quiescent conditions) to high Kz (turbulent mixing) occur over very small time and space scales.; A one-dimensional biogeochemical model of dissolved oxygen and carbon dynamics for Mirror Lake was coupled to the Kz results from POM. The results indicate that aerobic and anaerobic decomposition of organic carbon occurs primarily in the water column, and the pond is thus under strong hydrological control. A "snow-globe" model for the physical transport of particle-associated bacteria is used to explain observations of the coupled physical and biogeochemical dynamics in Mirror Lake. This mode of coupled dynamics is likely to be significant for all shallow aquatic systems.
机译：浅水区（<3m）普遍存在，吸收大量的碳和养分，其内部过程可以对下游的生物地球化学通量产生重要的控制作用。这些浅层系统的特征是生物地球化学和物理动力学之间的紧密耦合。这项工作通过观察，理论和模型结果研究了这些耦合动力学。在康涅狄格大学的Mirror Lake（平均深度= 0.7m）上进行了观测，使用了一种新颖的系统，用于实时和实时数据处理和显示的高时空分辨率采样。日间分层/去铁化动力学通过控制垂直运输和混合的速率影响生物地球化学循环。可以根据水深和可见光的扩散衰减系数的乘积，用单个参数来预测地球化学意义上的白天分层。夜间分层是通过表面冷却来控制的，尤其是在微风下。使用势能异常作为水柱分层的综合量度，可以将昼夜分层/去饱和动力学建模为穿过空气-水界面的热通量，水深和漫射光衰减系数的线性函数。日间分层/去饱和动力学可以通过垂直涡流扩散率（Kz）进行量化。使用普林斯顿海洋模型（POM），这是一种适用于浅水内陆水体的三维海洋环流模型，表明Kz响应于昼间分层动态而在四个数量级上变化，并且从低Kz转变（静止状态） ）在很小的时间和空间尺度上达到高Kz（湍流混合）； Mirror Lake的一维溶解氧和碳动力学的生物地球化学模型与POM的Kz结果耦合。结果表明，有机碳的好氧和厌氧分解主要发生在水柱中，因此池塘受到了强大的水文控制。用于颗粒相关细菌物理传输的“雪球”模型用于解释对Mirror Lake中物理和生物地球化学动力学耦合的观察。这种耦合动力学模式对于所有浅水系统都可能很重要。

著录项

  • 作者

    Branco, Brett F.;

  • 作者单位

    University of Connecticut.;

  • 授予单位 University of Connecticut.;
  • 学科 Biogeochemistry.; Biology Limnology.
  • 学位 Ph.D.
  • 年度 2007
  • 页码 223 p.
  • 总页数 223
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 生物地球化学、气体地球化学;
  • 关键词

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