Lake biogeochemical dynamics: the conveyor belt between physics and biology

建议的研究计划侧重于耦合的地球化学循环在北方湖泊。本研究的背景是，在湖泊水质受到多重压力，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）以及元素负荷的变化。我们缺乏知识和定量工具来预测湖泊对这些持续变化的反应，这限制了我们采取行动防止或减轻其恶化的能力。我们的目标是获得，使用数据和模型，耦合地球化学循环之间的复杂的相互作用和他们的外部和内部的压力影响湖泊的响应的定量理解。具有化学，生物学，生物信息学和工程背景的学生将获得研究机会和国际视野。** 研究计划的首要目标是了解湖泊中耦合地球化学循环对空间尺度上多种压力的响应。它将侧重于化学元素的循环，即碳（溶解和颗粒碳、二氧化碳和甲烷）、氧、营养物（磷和氮）、金属（铁、锰和铝）和微量元素（如，As、Se、Mo）。从理论的角度来看，我们感兴趣的是确定网络的耦合过程在地球化学循环，维持水质对比湖泊，并在量化未来的湖泊功能取决于他们过去的历史。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分开。拟议的研究活动涉及三个主题：（1）湖泊沉积地球化学受外部和内部营养负荷的影响，（2）湖泊氧动力学，特别是季节性缺氧，对辐照度，冰物候和有机物负荷的响应，沿着纬度生物气候梯度到达加拿大北极，（3）区域尺度湖泊物理和地球化学动态过程模拟。**

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. **