The release of carbon and pollutants from eastern canadian watersheds in response to atmospheric deposition and climate change

加拿大东部流域因大气沉降和气候变化而释放的碳和污染物

• 批准号: 576724-2022
• 负责人: Lapierre, JeanFrançoisJF
• 金额: $ 2.7万
• 依托单位: Université de Montréal
• 依托单位国家: 加拿大
• 项目类别: Alliance Grants
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=765156
• 关键词: release; carbon; pollutants; eastern; canadian

Canada's temperate and boreal landscapes host among the highest amounts and densities of lakes on earth. These lakes, most of them being hundreds to thousands of kilometers away from direct human activities, are experiencing changes in climate and atmospheric deposition of pollutants that disrupt the carbon and contaminant cycles, from their watershed to their water column. Past research has shown that lakes pH and concentrations of dissolved organic carbon (DOC) have been increasing in response to recovery from acidification, following legislation changes in the wake of widespread acid rain issues. These increases, which would in principle represent a return to pre-acidification conditions, have been accompanied by a loss in water transparency and shifts in thermal stratification, an increase in greenhouse gases emissions from aquatic ecosystems, and economic and health issues regarding drinking water treatment. Deposition of nitrogen and mercury have also decreased over the last decades, but the timing and amplitude of this decrease differed, and mercury persistence in watersheds may differ from that of ions and carbon. The cumulative effects of these trends in atmospheric deposition on the carbon and mercury cycles of Canadian temperate and boreal watersheds and lakes thus remain poorly understood. This proposal aims at filling this knowledge gap by building on extensive data available at Environment and Climate Change Canada at different spatial and temporal extents, including 100 lakes that have been sampled yearly since 1984 and 4 watersheds with contrasting climate and tree cover that have been monitored on a weekly basis since for several years in eastern Canada for geochemical properties in the water of lakes, streams, soils, throughfall and precipitation. We will complement these datasets by adding measurements of the composition of DOC as well as the concentrations of nutrients and different forms of total and methylated mercury in the water column of lakes and in key watershed compartments. Doing so, we will be able to better understand how industrial activities affect multiple facets of water quality at different spatial and temporal scales.

加拿大的温带和北方景观是地球上湖泊数量和密度最高的地方。这些湖泊，其中大多数距离人类直接活动数百至数千公里，正在经历气候变化和污染物的大气沉积，破坏了从流域到水体的碳和污染物循环。过去的研究表明，湖泊的pH值和溶解有机碳（DOC）的浓度一直在增加，以应对酸化的恢复，在广泛的酸雨问题之后，立法的变化。这些增加在原则上代表着回到酸化前的状况，伴随着水透明度的丧失和热分层的变化，水生生态系统的温室气体排放增加，以及饮用水处理方面的经济和健康问题。氮和汞的沉积在过去几十年中也有所减少，但这种减少的时间和幅度不同，汞在流域中的持久性可能不同于离子和碳。因此，对大气沉积的这些趋势对加拿大温带和北方流域和湖泊的碳和汞循环的累积影响仍然知之甚少。该提案旨在填补这一知识空白，方法是利用加拿大环境和气候变化部在不同空间和时间范围内提供的大量数据，包括自1984年以来每年对100个湖泊进行采样的数据，以及自几年来每周在加拿大东部监测4个气候和树木覆盖情况截然不同的流域，以了解湖泊、溪流、土壤、穿透雨和降水。我们将补充这些数据集，增加测量DOC的组成以及营养物质的浓度和不同形式的总汞和甲基化汞在湖泊的水柱和关键的分水岭隔间。这样，我们将能够更好地了解工业活动如何在不同的空间和时间尺度上影响水质的多个方面。