Aquatic greenhouse gas cycling in the face of global change: refining process-based understanding for enhanced predictive capabilities

淡水排放大量的温室气体（GHG），即二氧化碳（CO2）、甲烷（CH4）和一氧化二氮（N2O）。在全球范围内，这些排放量相当于化石燃料燃烧产生的碳排放量的6%，相当于土地利用变化产生的碳排放量的33%。最近的证据表明，人为（即人类引起的）活动和气候变化正在加剧水生温室气体排放，特别是通过富营养化，这是一种导致藻类过度生长的养分积累。这种生产降低了水质，分解后产生了大量的温室气体。营养物质的积累通常来自农业施肥或城市人口排放的废水，并因气候变化导致的径流增加而加剧。南安大略是一个人口稠密的农业区，但人们对安大略水域的温室气体状况知之甚少。这些知识对于制定解决方案以减轻淡水对气候的影响是必要的。我的研究项目的目标是促进我们对人类活动和气候变化如何改变这三种水生温室气体预算的理解，并开发预测预算的工具。为此，我将量化从滑铁卢-基奇纳和多伦多地区到阿尔冈昆省立公园附近更无人居住的地区的一系列湖泊中的水生温室气体排放和积累。此外，我们对冰下温室气体动力学的了解非常有限，除了在结冰时排放是显著的。因此，我建议在多塞特环境科学中心（DESC）的两个湖泊中量化和定义冰下温室气体动态，该中心配备了收集全年数据的浮标。联合国最近认识到水与气候之间的密切联系，敦促各国推行气候友好型水政策。加拿大拥有世界上约40%的淡水资源，可以成为水气候科学的领导者。目前的加拿大联邦可持续发展战略建议采取行动应对气候变化和保护水道，但这两个目标是相互排斥的，而且重点关注的大多是大型湖泊。我的研究将帮助加拿大环境和气候变化部实现他们的目标，通过使用我的项目结果确定其他地区较小的脆弱系统，并确定管理减少淡水对气候影响的流域活动的政策。此外，我在这里提出的研究将涉及几名本科生和研究生，他们将在实地和/或实验室接受有关水质、温室气体和环境数据和样本的实践培训。他们将在碳预算、建模和书面和口头媒体交流他们的研究方面获得经验。我小组的学生将获得的技术和软技能将为他们在政府，工业或学术界的职位做好准备，他们可以帮助推进加拿大的环境议程。

Freshwaters emit significant amounts of greenhouse gases (GHG), namely carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). Globally, these emissions are equivalent to ~6% of carbon emissions from fossil fuel burning and ~33% of that from land use change. Recent evidence suggests that anthropogenic (i.e., human-induced) activities and climate change are exacerbating aquatic GHG emissions, particularly via eutrophication, which is nutrient buildup that leads to excessive algal growth. This production reduces water quality and upon decomposition of it significant quantities of GHGs are produced. The nutrient buildup is typically sourced from fertilizer use in agriculture or wastewater release from urban populations and enhanced by increased runoff due to climate change. Southern Ontario is a populated region with much agriculture, yet little is known about the state of GHGs from Ontario waters. This knowledge is necessary to develop solutions to mitigate the climatic impact of our freshwaters. The goal of my research program is to advance our understanding of how human activities and climate change alter the budgets of all three aquatic GHGs and develop predictive tools for estimating budgets. To do this, I will quantify aquatic GHG emissions and accumulation in a series of lakes from the Waterloo-Kitchener and Toronto areas up to the more uninhabited regions near Algonquin Provincial Park. In addition, our understanding of GHG dynamics under ice is highly limited except that emissions at ice-off are significant. Therefore, I propose to quantify and define under ice GHG dynamics at two lakes at Dorset Environmental Science Centre (DESC) outfitted with buoys collecting year-round data. The United Nations recently recognized the intimate link between water and climate, urgin nations to pursue climate-friendly water policies. With ~40% of the world's freshwater, Canada can become a leader in water-climate science. The current Federal Sustainable Development Strategy of Canada recommends action on climate change and protection of waterways, but these are mutually exclusive goals and the lakes focused on are mostly large ones. My research will aid Environment and Climate Change Canada in fulfilling their goals by identifying smaller vulnerable systems in other regions using the results from my project and identify policies to manage watershed activities that reduce the climatic impact of our freshwaters. Also, the research I propose here will involve several undergraduate and graduate students who will receive hands-on training in the field and/or laboratory working on water quality, GHG and environmental data and samples. They will gain experience in carbon budgeting, modeling and communicating their research in written and oral media. The technical and soft skills that students in my group will obtain will prepare them for positions within government, industry or academia where they can help advance the environmental agenda of Canada.