RII Track-4: NSF: Source fingerprinting of mercury isotopes in thermokarst lake systems

存在于北半球大部分地区的永久冻土是汞的巨大储存库。目前尚不清楚永冻层中的汞在多大程度上可被生物体和食物网吸收。因此，这项研究将为一项为期两年的研究金提供资金，以通过访问、培训和在美国地质调查局汞研究实验室(USGS MRL)进行合作，提高阿拉斯加大学费尔班克斯大学(UAF)一名非终身教职研究助理教授的研究能力。这项研究将通过测量环境样品中汞的自然丰度同位素比率来调查沿永久冻土梯度的湖泊系统中汞的去向。USGS MRL的研究小组是国际公认的，并拥有一个国家最先进的实验室，配备有专门的仪器，用于高精度和精确地测量汞同位素比率。首席研究员将参加延长的访问，以学习适当的采样技术，并与美国地质调查局的科学家合作，分析从北部湖泊系统收集的环境样本。在合作访问期间获得的技能将使UAF和阿拉斯加州在处理与气候变化有关的复杂问题时受益。此外，这项研究将填补与永冻层释放的汞的去向有关的知识空白。这项研究基础设施改进Track-4 EPSCoR研究人员(RII Track-4)项目将为阿拉斯加大学费尔班克斯大学的一名研究助理教授提供奖学金。这项工作将与威斯康星州麦迪逊的美国地质调查局汞研究实验室(USGS MRL)的研究人员合作进行。最近的估计表明，永久冻土是汞的重要储存库，由于气候变化，汞很容易释放出来。热岩溶湖泊迅速降解永久冻土，因此，热岩溶湖泊在动员永久冻土储存的汞方面可能特别重要。这些系统中汞的环境命运仍然是一个重大的知识空白。自然丰度汞同位素比值的测量处于当前汞研究的前沿，是汞来源识别的有力工具，可以提供对汞生物地球化学循环的更多了解。到目前为止，大多数汞同位素研究都是在较低纬度系统进行的。因此，描述永冻层汞的同位素端元的信息有限，这将对研究人员大有裨益，因为他们试图确定这一潜在的重要汞来源对北极食物网的命运。首席研究员将对USGS MRL进行长期访问，在那里他将利用最先进的科学仪器，并学习与汞同位素分析有关的适当环境采样、分析和解释技能。在USGS MRL，首席研究员还将与USGS专家合作，分析从横跨纬度和融化梯度的热喀斯特湖泊收集的空气、水、沉积物、永久冻土和新兴昆虫样本中汞的自然丰度同位素比率。通过这些分析，研究小组将确定永久冻土汞进入当代热岩溶湖泊食物网的程度。这项研究的结果将被广泛传播。首席研究员将访问阿拉斯加原住民社区，讨论环境汞研究，并将在会议报告和同行评议出版物中传播项目结果。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Permafrost soils, which are present across a large portion of the Northern Hemisphere, are a vast reservoir for mercury. It remains unclear to what extent permafrost-derived mercury is available for uptake into organisms and food webs. Accordingly, this research will provide funding for a two-year fellowship to increase the research capacity of a non-tenure track Research Assistant Professor at the University of Alaska Fairbanks (UAF) through visits, training, and collaboration at the United States Geological Survey Mercury Research Laboratory (USGS MRL). This research will investigate the fate of mercury in lake systems along a permafrost gradient through the measurement of natural abundance isotope ratios of mercury in environmental samples. The USGS MRL’s research group is internationally recognized and maintains a state-of-the-science laboratory equipped with dedicated instrumentation for high accuracy and precision measurements of mercury isotope ratios. The lead researcher will participate in extended visits to learn appropriate sampling techniques and collaborate with USGS scientists to analyze environmental samples collected from the northern lake systems. The skills gained during the collaborative visits will benefit UAF and the State of Alaska as they tackle the complex problems associated with climate change. Additionally, the research will fill knowledge gaps related to the fate of mercury released from permafrost.This Research Infrastructure Improvement Track-4 EPSCoR Research Fellows (RII Track-4) project would provide a fellowship to a Research Assistant Professor at the University of Alaska Fairbanks. This work would be conducted in collaboration with researchers at the United States Geological Survey Mercury Research Laboratory (USGS MRL) in Madison, Wisconsin. Recent estimates indicate that permafrost soils are a significant reservoir of mercury, which is vulnerable to release due to climate change. Thermokarst lakes degrade permafrost rapidly and thus, thermokarst lakes may be particularly important in mobilizing mercury from permafrost stores. The environmental fate of mercury in these systems remains a major knowledge gap. The measurement of natural abundance mercury isotope ratios, which is at the forefront of current mercury research, is a powerful tool for mercury source identification and can provide additional understanding of mercury biogeochemical cycling. To date, most mercury isotope studies have been carried out in lower latitude systems. Thus, there is limited information characterizing the isotopic endmember of permafrost mercury, which would be of great benefit to researchers as they attempt to determine the fate of this potentially important source of mercury to Arctic food webs. The lead researcher will make extended visits to the USGS MRL, where he will make use of state-of-the science instrumentation and learn the appropriate environmental sampling, analytical, and interpretation skills related to mercury isotope analyses. While at the USGS MRL, the lead researcher will also work collaboratively with USGS experts to analyze natural abundance isotope ratios of mercury in samples of air, water, sediment, permafrost soil, and emergent insects collected from thermokarst lakes spanning a latitudinal and thaw gradient. By means of these analyses, the research team will identify to what extent permafrost mercury is entering contemporary thermokarst lake food webs. Results of this research will be communicated broadly. The lead researcher will make visits to an Alaska Native community to discuss environmental mercury research and will disseminate project results in conference presentations and peer-reviewed publications.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.