A process-based model for assessing the impacts of reservoirs and forest harvesting on the carbon budget of aquatic aquatic ecosystems

森林采伐和水库蓄水等人类活动对全球碳循环产生了深刻影响，特别是对陆地生态系统的大气二氧化碳（CO2）排放产生了深刻影响。水库蓄水导致发生在水柱和沉积物中的地球化学过程的瞬态和永久性的变化，而森林采伐强烈修改陆地有机质（TOM）的水生生态系统的通量。作为与政府伙伴合作努力的一部分，（加拿大环境部，Ministère du Dédépement Durable，de l 'Environnement et des Parcs du Québec），我们建议利用分析有机地球化学的最新进展，对（i）负责水生系统中TOM降解或螯合的因素，以及（ii）森林采伐和水库蓄水对这些因素在流域尺度上的温室气体（GHG）排放预算变化的影响。为了推广我们的方法，并验证我们的结论在全国各地的水生生态系统，我们将开发一个新的基于过程的模型（集成碳循环模型- ICC模型）连接陆地和水生生态系统。该模型将使用一个简短的水生生物地球化学示踪剂清单，以整合（i）湖泊或水库中的碳动态，以及（ii）由于森林采伐而导致的TOM输出的修改，最终提供这些对比环境中的温室气体排放预算估计值。最终目标是生成并向我们的政府合作伙伴转移生物地球化学和建模知识，以帮助他们确定此类干扰对水生生态系统人为温室气体排放或清除的长期影响和重要性。

Human activities such as forest harvesting and reservoir impoundment have profoundly impacted the global carbon cycle and, in particular, the atmospheric carbon dioxide (CO2) emissions of land ecosystems. Reservoir impoundment leads to transient and permanent changes in the biogeochemical processes taking place in the water column and the sediments, while forest harvesting strongly modifies the fluxes of terrestrial organic matter (TOM) to aquatic ecosystems. As part of a collaborative effort with governmental partners (Environment Canada, Ministère du Développement Durable, de l'Environnement et des Parcs du Québec), we propose to exploit the latest advances in analytical organic biogeochemistry to develop a fine molecular understanding of (i) the factors responsible for the degradation or sequestration of TOM in aquatic systems, and (ii) the impact of forest harvesting and reservoir impoundment on these factors in terms of changes in the greenhouse gas (GHG) emissions budget at the watershed scale. To generalize our approach and verify our conclusions in aquatic ecosystems across the country, we will develop a new process-based model (Integrated Carbon Cycle Model - ICC model) linking the terrestrial and aquatic ecosystems. This model will use a short list of aquatic biogeochemical tracers to integrate (i) carbon dynamics in lakes or reservoirs, and (ii) modifications in TOM exports due to forest harvesting, to ultimately provide estimates of GHG emission budgets in these contrasting environments. The ultimate goal is to generate and transfer biogeochemical and modeling knowledge to our governmental partners to assist them in determining the long-term effects and significance of such disturbances in relation to anthropogenic GHG emissions or removals from aquatic ecosystems.