Impacts of stratified environmental flows upon the distribution of sediment and biology in lakes and the coastal ocean

分层环境流对湖泊和沿海海洋沉积物和生物分布的影响

• 批准号: RGPIN-2022-04820
• 负责人: Wells, Mathew
• 金额: $ 3.72万
• 依托单位: University of Toronto
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=762183
• 关键词: Impacts; stratified; environmental; flows; upon

A key feature of almost all lakes and coastal seas is that they are density stratified, with lighter water floating above the deep denser layers. This stratification has critical consequences for sediment deposition, under-ice circulation, and fish habitat. However, substantial questions remain about the fundamental fluid dynamics controlling stratification and mixing in Canadian waters. In order to accurately interpret sedimentary records, we need to know how stratification in coastal seas changes where sediment from a river is deposited. To investigate the food chain under the ice in the frozen lakes of Canada, we need to understand the impact on mixing principles of the inverted, winter stratification that occurs when water is between 0-4 Celsius. To identify where fish dwell in lakes during summer, we need to understand how internal waves in thermally-stratified layers affect the regimes of cold blooded animals. This proposal will determine fundamental physical processes of stratification of significant geological, ecological, and economic importance to Canada. To address real-world stratification problems, the applicant and team will use an innovative combination of laboratory fluid dynamics experiments, theory, modelling and field observations in three different environmental systems. We will employ novel lab experiments and field studies on the Fraser River in BC to quantify how convection controls particle sedimentation rates from river plumes, providing a conceptual framework to understand sediment transport from the land to the ocean. Fieldwork on frozen lakes in southern Ontario will probe under-ice circulation patterns to elucidate the consequences of changing thermal and light conditions upon winter food chains. Our deeper physical understanding of winter inverse stratification will then drive new collaborative work with investigators in other Northern countries. Finally, the proposed work will determine the influence of internal waves in stratified lakes upon fish species distribution, capitalizing on the very large acoustic fish telemetry datasets available for Lake Ontario and building on existing collaborations with fisheries scientists. Taken together, this research is essential and urgent to improve our understanding of how our many stratified lakes and marine systems function. These efforts will train at least 20 HQP in an environment committed to inclusion. They will receive high-level training in environmental fluid dynamics, lab and field-based studies, as well as in developing theory and in performing data analysis that will prepare them for a broad range of opportunities in academia, government or private industry. Ultimately, my research program on environmental fluid dynamics will identify how sediment and biology distributions in different water bodies could shift as the warming climate changes the density stratification of these systems.

几乎所有湖泊和沿海海域的一个主要特征是，它们是密度分层的，较浅的水漂浮在较深的密度较高的层之上。这种层化对沉积物沉积、冰下循环和鱼类栖息地具有严重影响。然而，关于控制加拿大水域分层和混合的基本流体动力学仍然存在实质性的问题。为了准确地解释沉积记录，我们需要知道沿海海域的层化如何改变河流沉积物的沉积位置。为了研究加拿大冰冻湖泊中冰下的食物链，我们需要了解当水在0-4摄氏度之间时发生的倒转的冬季层结对混合原理的影响。为了确定夏季鱼类在湖泊中的栖息地，我们需要了解热成层中的内波如何影响冷血动物的状况。这项提议将决定对加拿大具有重大地质、生态和经济重要性的分层的基本物理过程。为了解决真实世界的分层问题，申请者和团队将在三个不同的环境系统中使用实验室流体动力学实验、理论、建模和现场观测的创新组合。我们将在不列颠哥伦比亚省的弗雷泽河上进行新颖的实验室实验和实地研究，以量化对流如何控制河流羽流中的颗粒沉积速率，为理解沉积物从陆地到海洋的运输提供一个概念框架。对安大略省南部冰冻湖泊的实地考察将探索冰下循环模式，以阐明变化的热和光条件对冬季食物链的影响。我们对冬季逆层结的更深入的物理理解将推动与其他北方国家的研究人员进行新的合作。最后，拟议的工作将确定分层湖泊中的内波对鱼类物种分布的影响，利用安大略湖现有的非常大的声学鱼类遥测数据集，并建立在与渔业科学家现有合作的基础上。综上所述，这项研究对于提高我们对许多分层湖泊和海洋系统如何发挥作用的理解是必要和紧迫的。这些努力将在一个致力于包容的环境中培训至少20名HQP。他们将接受环境流体动力学、实验室和实地研究方面的高级培训，以及开发理论和执行数据分析方面的培训，这将使他们为学术界、政府或私营行业的广泛机会做好准备。最终，我的环境流体动力学研究项目将确定，随着气候变暖改变这些系统的密度分层，不同水体中的沉积物和生物分布可能会发生变化。