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地球化学热点，在土地利用、土地覆盖、水文和气候方面经历着快速的自然和人为变化。这些变化影响水生生态系统功能的途径，但是，仍然知之甚少，由于规模脱节，限制了知识转移之间的地方，过程为基础的研究和大规模，模式为基础的研究，在水生生物地球化学。在景观生态学和水生生态地球化学的接口进行研究，我建议制定缩放原则，将允许桥梁的本地过程和大尺度的模式，在水生碳和养分循环。主要的重点是生态和地球化学过程之间的耦合，沿着共同的环境梯度，决定了时间和空间格局的水生溶解有机物（DOM），一个主变量，直接和间接的影响，几乎每一个过程中发生的水柱的湖泊和河流。该计划的主要目标是：1）确定改变DOM化学计量对跨时间水文梯度的水生生态化学的影响，2）评估跨空间景观梯度的水文格局的可扩展性和3）比较气候，土地覆盖和土地利用对DOM格局的影响在大陆尺度。依靠分析方法，协作网络，建模能力和自动化传感器的快速发展，我的计划将结合联合收割机的时间和空间的实地工作组件周围的蒙特利尔大学在魁北克省劳伦特地区的野外站设施，与现有的湖沼学和地理数据的分析，收集了超过50 000个湖泊在美国东北部，安大略和魁北克省。这一计划代表着朝着解开气候和土地利用的快速变化驱动大陆流域陆地碳和营养物命运的途径迈出了关键一步。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、土地使用和水文方面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.