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

Lakes are especially numerous in the arctic region, 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 their ice-covered period. However, under ice circulation affects the background hydrodynamic state 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. In this study, we propose to carry out several goals: (1) to quantify physical controls on under ice thermal structure and circulation, mixing of snow melt waters and mixing during spring and fall (2) to quantify respiration rates in arctic lakes of differing morphology and geological substrates (3) to illustrate the linkages and feedbacks between these physical and biogeochemical processes. The proposed research will be carried out in lakes being studied by the Artic Long Term Ecological Research (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. We measured time series of water temperatures, specific conductance and dissolved oxygen at several depths from a taut-line moored chain of loggers in different seasons (summer and winter) and across multiple years.北极地区湖泊分布广泛，约占该区域领土总面积的四分之一。一年之中，北极湖泊的水体有近九个月处于冰封状态。尽管冰封期漫长，但针对此类湖泊冰封期湖沼学（limnology）特征——包括生物学、化学与物理特性——的研究却相对匮乏。然而，冰下环流会对湖泊夏季的背景水动力状态产生影响。本研究旨在解析湖泊的全年环流循环，以量化水动力作用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研究背景之中。本研究设定了三项核心目标：（1）量化冰下热结构与环流、融雪水混合以及春秋季混合过程的物理控制机制；（2）量化不同形态与地质基底的北极湖泊的呼吸速率；（3）阐明上述物理过程与生物地球化学过程之间的关联及反馈机制。本项拟开展的研究将依托北极长期生态研究（Arctic Long Term Ecological Research, LTER）计划已开展监测的湖泊进行，所选湖泊包括图利克湖（Toolik Lake）、E1湖、E5湖、E6湖与N2湖。这些湖泊的面积介于1至1500公顷之间。本研究在不同季节（夏季与冬季）历经多年，通过张紧式锚定的多深度记录仪链，获取了不同水深下的水温、比电导率与溶解氧时间序列数据。