Time series of water temperature, specific conductance and oxygen from Lake E1, North Slope, Alaska, 2012-2013

Lakes are abundant in the terrestrial arctic, extending over about one quarter of the territory. For approximately nine months of the year, the waters of arctic lakes are under ice. Despite the duration of the ice-covered period, few studies have addressed the limnology (biological, chemical, and physical features) of these lakes during winter and how conditions under ice affects the stratification of lakes during the summer. We aim to look at the full year cycle lake circulation in order to quantify the effects of hydrodynamics on nutrient and gas fluxes and place the results within the context of climate change in the Arctic. The goals of our study include: (1) quantifying physical and biogeochemical controls on under ice thermal structure and circulation, the flowpath of snow melt, and mixing during spring and fall (2) quantifying respiration rates in arctic lakes of differing morphology and on geological substrates (3) illustrating the linkages and feedbacks between these physical and biogeochemical processes. Our research is being conducted in lakes studied by the Arctic Long Term Ecological Research (ARC LTER). The selected lakes are: Toolik Lake, Lake E1, Lake E5, Lake E6 and Lake N2. The Lakes range in size from 1 to 1500 hectares. Time series of water temperatures, specific conductance and dissolved oxygen at several depths were obtained from a taut-line mooring in different seasons (summer and winter) across multiple years (between fall 2012 and fall 2016).

陆地北极地区湖泊广布，水域面积约占该区域总面积的四分之一。北极湖泊全年有约九个月处于冰封状态。尽管冰封期漫长，但目前鲜有研究聚焦北极湖泊冬季的湖沼学（limnology，涵盖生物、化学及物理特征研究）特征，以及冰封期水下环境如何影响夏季湖泊的水体分层现象。本研究旨在探究湖泊全年环流周期，以量化水动力过程对营养盐与气体通量的影响，并将研究结果置于北极气候变化的背景下进行分析。本研究的目标包括：（1）量化冰封期热结构与环流、融雪径流路径以及春秋季混合过程的物理与生物地球化学调控机制；（2）量化不同形态特征且发育于不同地质基底上的北极湖泊的呼吸速率；（3）阐明上述物理与生物地球化学过程之间的关联与反馈机制。本研究依托北极长期生态研究计划（Arctic Long Term Ecological Research, ARC LTER）项目已调研的湖泊开展。入选的湖泊包括：图利克湖（Toolik Lake）、E1湖、E5湖、E6湖以及N2湖。这些湖泊的面积介于1至1500公顷之间。研究团队于2012年秋季至2016年秋季的多个年份，在夏季与冬季等不同季节，通过张紧式锚系设备获取了不同深度的水温、比电导率以及溶解氧时间序列数据。