Lake biogeochemical dynamics: the conveyor belt between physics and biology

建议的研究项目侧重于北方湖泊的耦合生物地球化学循环。本研究的背景是湖泊水质受到多种压力因素的影响，导致湖泊的地球化学和生态变化。这些压力因素包括气候变化（影响温度、辐照度、风和降水）和元素负荷的变化。我们缺乏预测湖泊对这些持续变化的反应的知识和定量工具，这限制了我们采取行动防止或减轻其恶化的能力。我们的目标是利用数据和模型，定量了解耦合生物地球化学循环及其对影响湖泊的外部和内部压力的响应之间的复杂相互作用。具有化学、生物学、生物信息学和工程学背景的学生将获得研究机会和国际视野。研究计划的总体目标是了解湖泊中耦合生物地球化学循环对跨空间尺度多重压力的响应。它将侧重于化学元素的循环，即碳（溶解和颗粒C， CO2和CH4）， O，营养物质（P和N），金属（Fe， Mn和Al）和微量元素（例如As， Se, Mo）。从理论的角度来看，我们感兴趣的是确定生物地球化学循环中维持不同湖泊水质的耦合过程网络，并量化未来湖泊的功能如何取决于它们的过去历史。利用模型，我们将把不断变化的外部环境压力与累积的内部压力区分开来。拟开展的研究活动分为三个主题：(1)受外部和内部营养负荷影响的湖泊沉积地球化学；(2)湖泊氧动力学，特别是季节性缺氧，对辐射、冰物候和有机质负荷的响应，沿着纬度生物气候梯度到达加拿大北极；(3)区域尺度上的湖泊物理和生物地球化学动力学面向过程的建模。

The proposed research program focuses on coupled biogeochemical cycles in northern lakes. The context of this research is that water quality in lakes is impacted by multiple stressors, causing geochemical and ecological changes in lakes. Such stressors include climate change (impacting temperature, irradiance, wind and precipitation), and changing loads of elements. We lack the knowledge and quantitative tools to predict lake responses to these ongoing changes, which limits our capacity to act to either prevent or mitigate their deterioration. Our aim is to acquire, using data and models, a quantitative understanding of the complex interplay between coupled biogeochemical cycles and their responses to external and internal pressures affecting lakes. Students with backgrounds in chemistry, biology, bioinformatics and engineering will be provided with research opportunities and an international outlook. The overarching objective of the research program is to understand the response of coupled biogeochemical cycles in lakes to multiple pressures across spatial scales. It will focus on the cycles of chemical elements, namely carbon (dissolved and particulate C, CO2 and CH4), O, nutrients (P and N), metals (Fe, Mn and Al) and trace elements (e.g., As, Se, Mo). From a theoretical standpoint, we are interested in identifying the network of coupled processes in biogeochemical cycles that sustain water quality in contrasting lakes, and in quantifying how future lake functioning depends on their past history. Using models, we will disentangle changing external environmental pressures from accumulated internal pressures. The proposed research activities are distributed across three themes: (1) the sedimentary geochemistry of lakes affected by external and internal nutrient loads, (2) the response of lake oxygen dynamics, and in particular seasonal anoxia, to irradiance, ice phenology and organic matter loads along a latitudinal bioclimatic gradient reaching the Canadian arctic, and (3) the process-oriented modelling of physical and biogeochemical lake dynamics at the regional scale.