Collaborative Research: MEGA - Mercury biogeochemical cycling and export from Greenland to the Arctic

汞是一种有毒元素，对环境和人类的健康都有影响。由于大气中的汞主要从采矿和工业区迁移到北极，北极食物网中的汞含量特别高。北极汞的主要来源被认为是人类排放到大气中（例如，来自金矿开采和化石燃料燃烧中的材料加工），但也可能存在大量的汞自然来源，这些汞可能会随着气候变暖而发生变化。格陵兰岛的冰川和冰盖、大型冰河最近被确定为通过冰川物理研磨（当它们在景观中推平时）和融化而进入北极的汞的可能来源，但数据仍然稀少，这些现有的数据集突出了重大的不确定性。在MEGA项目中，研究人员将对（i）格陵兰岛上的一系列冰川融水河流，（ii）这些融水流入的海洋，以及（iii）水采样点附近的空气进行采样，以了解这些天然汞输入是否重要和/或是否可能随着气候变暖中冰川融化的增加而变化。这些新数据将提高我们对地球系统中冰川和冰盖重要性的认识，并利用现代测量技术提供关键的过程信息。MEGA项目最终将帮助我们了解汞如何在北极系统中移动和变化。MEGA将支持两名博士生，几名本科生和一些早期职业科学研究人员。它将建立美国、丹麦、德国、捷克和格陵兰研究人员之间的国际合作，并为西费城资源不足的高中教师提供参与北极研究的独特机会。汞是一种有毒元素，在食物网中积累和放大，使其成为人类特别关注的问题。北极地区的汞浓度尤其令决策者感到关切，因为北极海洋生物体内的汞浓度很高。这对北极社区来说很重要，因为他们的饮食很大程度上依赖于捕鱼和狩猎。北极地区汞的主要来源是低纬度地区人为汞的大气沉积（例如，手工采金和化石燃料燃烧），并通过主要的大气环流输送到极地地区。最近，来自永久冻土融化等自然来源的汞作为北极汞循环的潜在重要组成部分而受到关注，北极汞循环可能会在气候变暖时发生变化。然而，围绕这些对气候敏感但具有潜在重要性的汞自然来源，特别是冰川和冰盖，科学知识存在巨大差距。格陵兰冰盖是迄今为止北方最大的冰块，覆盖了北极20%以上的陆地表面。最近的研究表明，冰盖可能是周围海洋生态系统汞的重要来源，但数据有限，需要进行更多的研究。MEGA项目将制作第一个完整的汞从源（冰）到汇（海洋）的流动、移动和转化模型。调查人员将通过采样（i）从冰盖流出的融水河流，（ii）这些河流进入的沿海地区，以及（iii）汞可以沉积/运输的大气，为格陵兰岛的汞制定一个强大的数字预算。MEGA将使用创新的方法技术，如汞的化学指纹（例如，汞同位素比率），以提供信息，说明格陵兰冰盖过程在北极汞循环中的重要性。MEGA项目将支持各种各样的研究人员，包括本科生，两名研究生，一名早期职业博士后研究员和四名早期职业教师。该项目还将发展美国研究人员/机构与格陵兰、丹麦、捷克共和国和德国研究人员/机构之间的合作、网络和能力建设。MEGA还将安排两名来自费城的K-12教育工作者进行实地考察，以培养他们对STEM、北极研究和地球系统科学的兴趣，帮助激发他们的教学课程和学生。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

Mercury is a toxic element that is of concern for the health of the environment and humans. There are particularly high amounts of mercury in Arctic food webs due to the transport of mercury in the atmosphere to the Arctic, primarily from mining and industrial regions. The main source of mercury to the Arctic is thought to be human emissions to the atmosphere (for example, from processing of material in gold mining and fossil fuel burning), but there may also be large natural sources of mercury that could change with climate warming. Glaciers and ice sheets, large rivers of ice, have recently been identified in Greenland as possible sources of mercury to the Arctic through glacier physical grinding (as they bulldoze their way through the landscape) and melt, but data is still sparse and these existing datasets highlight significant uncertainty. In the MEGA project, the investigators will sample (i) a range of glacial meltwater rivers across Greenland, (ii) the oceans these meltwaters flow into, and (iii) the air next to the water sampling sites, to understand whether these natural mercury inputs are important and/or are likely to change with increased glacier melting in a warming climate. This new data will improve our knowledge of the importance of glaciers and ice sheets in the Earth System, and provide critical process information using modern measurement techniques. The MEGA project will ultimately help us understand how mercury moves and changes through Arctic systems. MEGA will support two PhD students, several undergraduates, and a number of early career scientific researchers. It will establish an international collaboration between US, Danish, German, Czech and Greenlandic researchers, and provide unique opportunities for teachers from under resourced high schools in West Philadelphia to participate in Arctic research.Mercury is a toxic element that accumulates and magnifies in food webs, making it of particular concern to human populations. Concentrations of mercury in the Arctic region are of particular concern for policymakers because they are high in Arctic marine organisms. This is important for Arctic communities that rely on fishing and hunting for significant proportions of their diet. The major source of mercury to the Arctic is atmospheric deposition of anthropogenic mercury from lower latitudes (for example, from artisanal gold mining and fossil fuel burning), transported to the polar regions by prevailing atmospheric circulation. More recently, natural sources of mercury, such as from permafrost melting, have received attention as potentially important components of the Arctic mercury cycle that could change in a warming climate. However, large gaps in scientific knowledge surround these climatically sensitive but potentially significant natural sources of mercury, particularly glaciers and ice sheets. The Greenland Ice Sheet is by far the largest ice mass in the northern hemisphere, covering over 20% of the land surface in the Arctic. Recent research suggests the ice sheet may be an important source of mercury to surrounding ocean ecosystems, but the data is limited and additional research is needed. The MEGA project will produce the first complete model of mercury mobilization, movement and transformations from source (ice) to sink (ocean). The investigators will develop a robust numerical budget for mercury in Greenland by sampling (i) meltwater rivers flowing from the ice sheet, (ii) the coastal areas these rivers enter, and (iii) the atmosphere from where mercury can be deposited/transported. MEGA will use innovative methodological techniques like the chemical fingerprint of the mercury (e.g., mercury isotope ratios) to provide information that contextualizes the importance of the Greenland Ice Sheet processes in the Arctic mercury cycle. The MEGA project will support a diverse range of researchers, including undergraduate students, two graduate students, an early career postdoctoral researcher, and four early career faculty. The project will also develop collaborations, networking and capacity building between US researchers/institutions and researchers/institutions from Greenland, Denmark, the Czech Republic and Germany. MEGA will also embed two K-12 educators from Philadelphia in fieldwork to cultivate interests in STEM, Arctic research, and Earth systems science, helping inspire their teaching curriculum and their students.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.