ABSTRACT

The Arctic has warmed significantly over the past decades. However, the evolution of Arctic climate during the Holocene remains to be clarified in more detail, and regional factors controlling aquatic ecosystem evolution need to be better defined to grasp the sensitivity of lakes to rapid environmental change. Nettilling Lake was studied for changes in sedimentary diatom assemblages over the last 5 000 years. Lake water pH was reconstructed by applying a diatom-based lake water pH inference model. We hypothesized that the changes in diatom assemblages were driven by variations in lake water transparency and attendant water turbidity associated with the input of fine suspended solids from glacial meltwaters. Reduced underwater light resulted in greater abundance of planktonic over benthic taxa from ca. 5 000 to 3 000 yrs. cal. BP, followed by less turbid conditions and proliferation of benthic taxa during regional cooling. The lake water was slightly alkaline throughout the Holocene, ranging between pH 7.1 and 7.7. Our results support the notion that hydrological processes, dependent on climate variations, have a first-order influence on the regulation of the lake water pH through glacial meltwater inputs, which will likely continue to control the lake’s long-term chemical and biological evolution.

摘要

北极在过去几十年中显着变暖。然而，全新世期间北极气候的演变仍有待更详细的阐明，需要更好地界定控制水生生态系统演变的区域因素，以掌握湖泊对环境快速变化的敏感性。研究了 Nettilling 湖在过去 5000 年中沉积硅藻组合的变化。通过应用基于硅藻的湖水 pH 推理模型重建湖水 pH 值。我们假设硅藻组合的变化是由湖水透明度的变化和伴随的与冰川融水细悬浮固体输入相关的水浊度的变化驱动的。水下光线减少导致浮游生物比来自约 100 年的底栖类群更丰富。5 000 至 3 000 年。卡尔。血压计，其次是在区域冷却期间混浊条件减少和底栖类群的增殖。整个全新世湖水呈微碱性，pH值介于7.1和7.7之间。我们的研究结果支持这样一种观点，即取决于气候变化的水文过程通过冰川融水输入对湖水 pH 值的调节产生一级影响，这可能会继续控制湖泊的长期化学和生物演化。