ABSTRACT

Northern lakes provide many ecosystem services, including the provision of traditional foods and clean water. These systems are vulnerable to climate-driven changes in hydrology and contaminant accumulation, but the direction and magnitude of projected changes are poorly constrained. One contaminant of concern is mercury; currently, we cannot accurately predict how mercury accumulation in lakes will respond to climate-induced changes, especially in lakes with glacial inflows and complex hydrology. Sediment cores collected from two regions of a glacially fed lake (Lhù’ààn Mân’; Kluane Lake, Yukon, Canada) were analyzed to investigate controls on sediment mercury accumulation in the context of previously described hydrological changes. Differences in catchment contributions drove differences in sediment mercury accumulation between lake regions during the Duke River hydrological period (ca. 750–1650). During the more recent Slims River hydrological period (ca. 1650–2015), mercury accumulation did not differ between regions, and mercury was delivered to the lake primarily via catchment organic matter and carbonate-rich sediments from the largest, glacially derived inflow (Slims River). Recent climate-induced geomorphic change caused loss of the main lake inflow (Slims River) in 2016, making Kluane Lake an ideal system for future investigations of how loss of glacial inflow will affect mercury accumulation in northern lakes.

摘要

北部湖泊提供许多生态系统服务，包括提供传统食物和清洁水。这些系统容易受到气候驱动的水文变化和污染物积累的影响，但预测变化的方向和幅度受到很大限制。一种值得关注的污染物是汞；目前，我们无法准确预测湖泊中的汞积累将如何应对气候引起的变化，特别是在有冰川流入和复杂水文的湖泊中。分析了从冰川补给湖 (Lhù'ààn Mân'; Kluane Lake, Yukon, Canada) 的两个区域收集的沉积物核心，以研究在先前描述的水文变化背景下对沉积物汞积累的控制。在杜克河水文时期（约 750-1650 年），流域贡献的差异导致湖泊区域之间沉积物汞积累的差异。在最近的斯利姆斯河水文时期（约 1650 年至 2015 年），汞的积累在地区之间没有差异，汞主要通过集水区有机物和来自最大的冰川来源的流入（斯利姆斯）的富含碳酸盐的沉积物输送到湖中。河）。最近气候引起的地貌变化导致 2016 年主要湖泊流入量（斯利姆斯河）的损失，使克鲁恩湖成为未来研究冰川流入量减少将如何影响北部湖泊中汞积累的理想系统。不同地区的汞积累没有差异，汞主要通过集水区有机物和来自最大的冰川流入（斯利姆斯河）的富含碳酸盐的沉积物输送到湖中。最近气候引起的地貌变化导致 2016 年主要湖泊流入量（斯利姆斯河）的损失，使克鲁恩湖成为未来研究冰川流入量减少将如何影响北部湖泊中汞积累的理想系统。不同地区的汞积累没有差异，汞主要通过集水区有机物和来自最大的冰川流入（斯利姆斯河）的富含碳酸盐的沉积物输送到湖中。最近气候引起的地貌变化导致 2016 年主要湖泊流入量（斯利姆斯河）的丧失，使克鲁恩湖成为未来研究冰川流入量减少将如何影响北部湖泊中汞积累的理想系统。