The carbon cycling of eastern Quebec boreal forests in the context of climate change and hydropower production

水电是魁北克人和加拿大人的主要电力来源，也是对美国越来越重要的出口产品。用于水电生产的水库洪水会排放二氧化碳和甲烷，这是两种重要的温室气体。与非可再生资源发电相比，这些排放量较低，但它们必须放在由于气候变化而迅速变化的环境中。事实上，除了水生和湿地生态系统外，水库还淹没了以前主要是森林的地区。人们通常认为这些是净碳汇，但在气候变暖时，这种情况可能会改变，那里的干旱、火灾和虫害疫情可能会变得更加频繁。因此，为了能够预测水电站对气候的净影响，我们需要了解完整的周围景观对气候的影响，以及这种影响是如何演变的。我们建议对位于魁北克省北部科特迪瓦地区的La Romaine分水岭这样做。La Romaine建筑群项目于2009年启动。2021年竣工后，该综合体将包括四座年产8.5太瓦时的水电站和四座水库，总面积为280平方公里。我们将监测拉罗缅纳河一个分流域的碳通量，确定该分流域内的碳储存热点，并确定从该分流域输出的碳在水中的去向。我们将使用这一详尽的实地研究结果来模拟拉罗曼因下游分水岭的碳功能，最终能够预测这一森林景观在碳循环中的作用。我们的项目不仅将有助于魁北克省(魁北克省)负责发电、输电和配电的公用事业公司评估水电生产的真实环境成本，还将更好地为加拿大部分依赖其森林的碳汇功能来缓解未来气候变化的战略提供参考。

Hydropower is the main source of electricity to Quebecers and to Canadians, and is an increasingly important export product to the US. Reservoir flooding for hydropower production emits carbon dioxide and methane, two important greenhouse gases. These emissions are low compared to electricity production from non-renewable resources, but they have to be put in the context of a rapidly changing environment due to climate change. Indeed, reservoirs flood areas that were previously largely forests, in addition to aquatic and wetland ecosystems. It is generally assumed that these are net carbon sinks, but this may change in a warmer climate, where droughts, fire and insect epidemics may become more frequent. Hence, to be able to project the net impact of hydropower reservoirs on the climate, we need to understand the impact of intact, surrounding landscapes on the climate, and how this impact evolves. We propose to do this for the La Romaine watershed located on the Côte Nord region of the province of Quebec. The La Romaine complex project was initiated in 2009. At completion in 2021, the complex will comprise four hydroelectric power plants yielding 8.5 TWh of energy per year and four reservoirs covering a total area of 280 km2. We will monitor the carbon fluxes of a subwatershed of La Romaine river, determine the carbon storage hotspots within the subwatershed, and determine the fate of carbon exported in the water from the subwatershed. We will use the results from this exhaustive field study to model the carbon functions of the lower La Romaine watershed, to eventually be able to project the role of this forested landscape in the carbon cycle. Our project will not only be useful to the utility responsible for generation, transmission, and distribution of electricity in the province of Quebec (Hydro-Québec) to assess the true environmental cost of hydropower production, but also to better inform Canada's strategy to partly rely on the carbon sink function of its forests to mitigate future climate change.