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

汞是一种有毒元素，它关系到环境和人类的健康。由于大气中的汞主要来自采矿业和工业区，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的汞(例如，黄金开采和化石燃料燃烧中的材料加工)，但也可能有大量的自然汞来源，这些来源可能会随着气候变暖而改变。格陵兰的冰川和冰盖是大型冰河，最近被确认为可能通过冰川物理碾磨(当它们在地貌中推土机)融化而进入北极的汞的来源，但数据仍然稀少，这些现有的数据集突显了重大的不确定性。在这个庞大的项目中，研究人员将采样(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)水样采样点旁边的空气，以了解这些自然汞输入是否重要和/或可能随着气候变暖冰川融化的增加而变化。这些新数据将提高我们对冰川和冰盖在地球系统中重要性的认识，并利用现代测量技术提供关键的过程信息。这个庞大的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的教师提供参与北极研究的独特机会。汞是一种有毒元素，在食物链中积累和放大，使其成为人类群体特别关注的问题。北极地区的汞浓度尤其令政策制定者担忧，因为它们在北极海洋生物中含量很高。对于依赖捕鱼和狩猎的北极社区来说，这一点很重要。北极汞的主要来源是来自较低纬度地区的人为汞在大气中的沉积(例如，手工开采黄金和燃烧化石燃料)，这些汞通过普遍的大气环流输送到极地地区。最近，汞的自然来源，例如来自永久冻土融化的汞，作为北极汞循环的潜在重要组成部分受到了关注，而北极汞循环可能会在气候变暖时发生变化。然而，这些对气候敏感但潜在重要的汞自然来源，特别是冰川和冰盖，在科学知识方面存在很大差距。格陵兰冰盖是迄今为止北半球最大的冰块，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，需要进行更多研究。这个庞大的项目将制作首个完整的汞动员、移动和从源(冰)到汇(海洋)的转化模型。研究人员将通过采样(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)可储存/运输汞的大气，来制定格陵兰汞的可靠数字预算。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。这个庞大的项目将支持一系列不同的研究人员，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。该项目还将促进美国研究人员/机构与格陵兰、丹麦、捷克共和国和德国的研究人员/机构之间的合作、联网和能力建设。Mega还将在实地工作中嵌入两名来自费城的K-12教育工作者，以培养人们对STEM、北极研究和地球系统科学的兴趣，帮助激励他们的教学课程和学生。这一奖项反映了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。

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.