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.

加拿大的温带和寒带地区拥有地球上湖泊数量和密度最高的地区之一。这些湖泊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大气污染物沉积，从而扰乱从流域到水柱的碳和污染物循环。过去的研究表明，随着酸雨问题的广泛发生，立法发生了变化，湖泊的 pH 值和溶解有机碳 (DOC) 的浓度随着酸化的恢复而不断增加。这些增加原则上意味着恢复到酸化前的条件，但伴随着水透明度的丧失和热分层的变化、水生生态系统温室气体排放的增加以及与饮用水处理有关的经济和健康问题。在过去的几十年里，氮和汞的沉积也有所减少，但减少的时间和幅度有所不同，流域中汞的持久性可能与离子和碳的持久性不同。因此，大气沉降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。该提案旨在通过利用加拿大环境与气候变化部在不同时空范围内提供的广泛数据来填补这一知识空白，其中包括自 1984 年以来每年采样的 100 个湖泊和 4 个具有对比气候和树木覆盖率的流域，这些流域多年来一直在加拿大东部每周监测湖泊、溪流、土壤、径流和降水的水的地球化学特性。我们将通过添加湖泊水柱和关键流域分区中 DOC 成分以及营养物浓度以及不同形式的总汞和甲基化汞的测量来补充这些数据集。这样做，我们将能够更好地了解工业活动如何在不同时空尺度上影响水质的多个方面。