Collaborative Research: Year-round autonomous sampling of methane in Arctic lakes

研究人员建议在整个北极冬季使用自主采样设备连续测量冰冻湖泊中的甲烷浓度，以更彻底地解决从北极湖泊到大气的甲烷通量的变化。甲烷是一种强有力的温室气体，随着气候变暖，北极地区甲烷的释放将会增加。该项目将在成功的试点研究基础上进行扩展，包括自主连续流体采样器和传感器系统的初步测试。拟议中的扩展将涉及额外的能力，并在加拿大北极麦肯齐河三角洲南北梯度的六个小湖泊中分别部署一个采样单元，为期9个月，跨越冬季。有了这些数据，研究人员的目标是描述水柱中的物理、化学和微生物条件，以阐明冬季期间的水文、微生物和风化过程，此时冰层下的湖水中会产生甲烷。研究人员假设，在春季洪水和冰盖破裂之后，突然（一周、几天甚至几小时）释放的甲烷产生了明显的北极湖泊大气通量，否则就会被遗漏，因为大多数合理的采样发生在夏季，这些湖泊的甲烷浓度很低或低于检测值。据估计，北极大气中的大部分甲烷通量来自土壤和小湖泊，尽管这些估计是基于很少的直接观测，具有很大的不确定性。这项拟议的研究，使用原位采样器和传感器，将允许广泛的微生物，气体和离子分析程序与物理和化学传感器数据网络相结合，以评估冬季的时间条件；确定基本过程和速率；确定微生物、地球化学和物理过程之间的相互作用；并制定一个更具包容性的研究计划，利用低成本的代用物来最好地表征湖泊条件的时间方面的重要过程。该项目将通过开发新的实地采样技术，加强北极未来研究的基础设施。该项目将支持几名本科生和研究生，为来自非研究密集型机构的学生提供宝贵的实验室经验。调查人员还将进行两次非正式的外联活动，向小学生传达北极气候变化的重要性，同时教他们设计和工程知识。他们还打算与加拿大因努维克的奥罗拉学院和奥罗拉研究所密切合作，吸引原住民青年。

The investigators propose to measure methane concentrations in frozen lakes continuously throughout the Arctic winter using autonomous sampling devices, to more thoroughly address the variability in the methane flux from Arctic lakes to the atmosphere. Methane is a potent greenhouse gas, the release of which from Arctic sources is poised to increase with climate warming. This project will expand upon a successful pilot study that included the initial testing of autonomous continuous fluid sampler and sensor systems. The proposed expansion will involve additional capabilities and the deployment of a sampling unit in each of six small lakes along a north-south gradient in the Mackenzie River delta in the Canadian Arctic for a nine-month period, spanning the winter season. With these data the investigators aim to characterize the physical, chemical, and microbial conditions in the water column to elucidate hydrologic, microbial, and weathering processes during the winter season, when methane builds in lake water under the ice cover. The investigators hypothesize that sudden (week, days, or even hours) releases of methane, following spring flooding and ice cover breakup, produce a distinct atmospheric flux from Arctic lakes that would otherwise be missed, since most logistically reasonable sampling occurs in the summer months when methane concentrations in these lakes are low or below detection.The majority of methane flux to the Arctic atmosphere is estimated to come from soils and small lakes, although these estimates are based on few direct observations with large uncertainties. This proposed study, using in situ samplers and sensors, will allow an extensive microbial, gas and ion analytical program coupled with a network of physical and chemical sensor data to assess temporal conditions during winter months; to confirm fundamental processes and rates; to determine the interplay among microbial, geochemical and physical processes; and to develop a plan for a more inclusive study that takes advantage of low cost proxies for significant processes that best characterize temporal aspects of lake conditions. The project will enhance infrastructure for future research in the Arctic through the development of novel in situ sampling. The project will support several undergraduate and graduate students, providing valuable lab-based experience for students from non-research-intensive institutions. The investigators also will conduct two informal outreach activities to communicate the importance of Arctic climate change to primary school students while also teaching them about design and engineering. They also intend to work closely with Aurora College and Aurora Research Institute based in Inuvik, Canada, to engage First Nations youth.