Bridging local processes and broad-scale patterns in aquatic biogeochemistry under rapid environmental changes

水生生态系统是复杂景观中的生物地球化学热点，它经历了土地利用、土地覆盖、水文和气候的快速自然和人类驱动的变化。然而，这些变化影响水生生态系统功能的途径仍然知之甚少，因为规模脱节限制了水生生物地球化学中基于过程的局部研究和基于模式的大范围研究之间的知识转移。在景观生态学和水生生物地球化学的界面上进行研究时，我建议制定尺度原理，以便在水生碳和养分循环中连接局部过程和大范围模式。主要侧重于沿共同环境梯度的生态和生物地球化学过程之间的耦合，这些过程决定了水生溶解有机物(DOM)的时间和空间格局，DOM是一个主变量，对湖泊和河流水柱中发生的几乎每一个过程都有直接和间接的影响。该计划的主要目标是：1)确定变化的DOM化学计量比对跨时间水文梯度的水生生物地球化学的影响；2)评估跨空间景观梯度的水文格局的可伸缩性；3)比较气候、土地覆盖和土地利用对大陆尺度DOM格局的影响。依托分析方法、协作网络、建模能力和自动化传感器的快速发展，我的项目将结合魁北克劳伦蒂斯地区蒙特雷亚尔大学野外站设施周围的时间和空间野外工作组件，以及对收集的美国东北部、安大略省和魁北克省50,000多个湖泊的现有湖水和地理数据进行分析。该计划代表着朝着解开气候和土地利用快速变化推动大陆流域陆地碳和养分命运的路径迈出的关键一步。这一认识反过来将使科学家和管理人员能够更好地预测湖泊和河流对气候、土地覆盖、土地利用和水文的复杂和相互作用的变化的反应，从而针对从地方到大陆规模的景观管理的最紧迫问题。

Aquatic ecosystems are biogeochemical hotspots in a complex landscape that undergoes rapid natural and human-driven changes in land-use, land-cover, hydrology, and climate. The pathways by which these changes affect aquatic ecosystem functioning, however, remain poorly understood due to the scale disconnect that limits knowledge transfer between local, process-based studies and broad-scale, pattern-based studies in aquatic biogeochemistry. Conducting research at the interface of landscape ecology and aquatic biogeochemistry, I propose to develop scaling principles that will allow to bridge local processes and broad-scale patterns in aquatic carbon and nutrient cycling. The main focus is on the coupling between ecological and biogeochemical processes along common environmental gradients that dictate the temporal and spatial patterns in aquatic dissolved organic matter (DOM), a master variable with direct and indirect influence on virtually every process occurring in the water column of lakes and rivers. The main objectives of the program are to: 1) determine the effects of changing DOM stoichiometry on aquatic biogeochemistry across temporal hydrological gradients, 2) assess the scalability of hydrological patterns across spatial landscape gradients and 3) compare the effects of climate, land cover and land use on DOM patterns at continental scale. Relying on the fast-growing development of analytical methods, collaboration networks, modeling capacity and automated sensors, my program will combine a temporal and a spatial field work components around the Université de Montréal field station facilities in the Laurentians region, Québec, with the analysis of existing limnological and geographical data assembled for over 50 000 lakes across the NE US, Ontario and Québec. This program represents a crucial step toward disentangling the pathways through which rapid changes in climate and land-use drive the fate of terrestrial carbon and nutrients in continental watersheds. This understanding, in turn, will allow scientists and managers to better forecast the response of lakes and rivers to complex and interacting changes in climate, land-cover, land-use and hydrology, and thus to target the most pressing issues for landscape management from local to continental scales.