Time series of water temperature, specific conductance and oxygen from Lake E1, North Slope, Alaska, 2014-2015

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).

北极陆地区域湖泊分布广泛，覆盖区域总面积的近四分之一。每年约有九个月的时间，北极湖泊的水体均处于冰封状态。尽管冰封期持续时间较长，但目前鲜有研究聚焦于冬季北极湖泊的湖沼学（limnology，即研究湖泊生物学、化学与物理特征的学科）特征，以及冰封条件如何影响夏季湖泊的分层现象。

本研究旨在探究湖泊全年循环过程，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开展分析。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) 测定不同形态学特征与地质基底条件下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（Arctic Long Term Ecological Research, ARC LTER）已开展调查的湖泊进行。本次选取的研究湖泊包括图利克湖（Toolik Lake）、E1湖、E5湖、E6湖与N2湖，湖泊面积介于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（taut-line mooring）设备获取了多深度点位的水温、比电导率（specific conductance）与溶解氧时间序列数据。