Transport and mixing of particles in stratified environmental flows.

加拿大毗邻世界上最大的内陆湖泊系统，并拥有世界上最长的海洋海岸线。要对这些重要的水生系统进行成功的环境管理，就需要清楚地了解沉积物、营养物质和化学物质是如何被稀释并从人口密集地区转移到敏感的生态栖息地的。在这笔拨款中，我们将重点关注粒子运输的三个基本方面的潜在物理过程：沉积物在海底积聚的地方，河流沉积物如何填充港口和河口，以及微塑料的扩散，这些微塑料会伤害我们湖泊中的鱼类。我的研究项目通过实验室实验、数学建模和实地研究来研究这些过程。在第一个目标中，我们将为海底一些最大沉积物的演变开发新的概念模型，并确定这些大型沉积物的形状如何受到洋流速度的影响。在第二个目标中，我们将解决河流中含有沉积物的水流进入分层湖泊或沿海海洋的情况，了解沉积物沉积的速度是很重要的，因为这决定了沉积物形成的规模。在第三个目标中，我们将确定风力驱动的湍流和洋流如何控制五大湖中浮力微塑料颗粒的垂直和水平扩散，这将是帮助政府机构管理这种形式的污染对环境影响的重要一步。

Canada borders the world's largest inland lake system, and has the world's longest ocean coastline. The successful environmental management of these important aquatic systems requires a clear understanding of how sediment, nutrients, and chemicals are diluted and transported from high-density population areas to sensitive ecological habitats. In this grant, we focus on the underlying physical processes of three basic aspects of particle transport: where sediment accumulates on the ocean floor, how sediments from rivers fill in harbours and estuaries, and the spread of micro-plastics, which hurt fish in our lakes. My research program studies these processes with laboratory experiments, mathematical modeling, and field studies. In the first aim, we will develop new conceptual models for the evolution of some of the largest sediment deposits on the ocean floor and determine how the shape of these large sediment deposits is influenced by the speed of the ocean currents. In the second aim, we will address the situation where a sediment-laden flow of a river enters into a stratified lake or the coastal ocean and it is important to know how fast the sediment settles, as this determines the scale over which sediments deposits form. In the third aim, we will establish how wind-driven turbulence and currents control the vertical and horizontal spread of buoyant micro-plastic particles in the Great Lakes, which will be an important step in helping government agencies manage the environmental impacts of this form of pollution. Overall, my internationally-recognized NSERC program of research is directed at understanding the physical processes that control transport and mixing of particles, chemicals and biology in stratified lakes and the coastal ocean. To keep my research rooted in urgent, practical concerns, I collaborate with environmental agencies at the federal, provincial and municipal levels. These partnerships have also allowed me to leverage additional funds for a larger program of fieldwork, and to ensure that our new science is used by relevant authorities to help formulate their management decisions. The proposed research will advance our understanding of environmental fluid dynamics relevant to Canada's socioeconomic and environmental needs.