Fugitive Gases (Helium, Neon, and Oxygen) in the WAIS Divide Ice Core as Tracers of Basal Processes and Past Biospheric Carbon Storage

1143619/Severinghaus该奖项支持一个项目，该项目旨在将对冰芯中气体的研究扩展到那些小分子直径导致它们迅速从冰样中逸出的气体(即所谓的“逃逸气体”)。这项工作将使用WAIS Divide冰芯中的氦、Ne、Ar和氧的测量，以更好地了解气体关闭分馏的机制，这种分馏是在气泡被合并到冰中时发生的。这项拟议工作的学术价值在于，使用霓虹灯(在大气中是恒定的)对这种分馏进行修正，最终可能实现第一个基于冰核的大气氧和氦记录。霓虹灯还可能阐明局部辐射和用于冰芯天文测年的氧气之间的机械联系。岩心最深处~100m处的氦测量也将揭示基冰的地层完整性，并作为西南极冰盖底部固体地冰相互作用的探测器。过去的大气氧记录(目前在CE之前无法获得)将揭示伴随着气候变化的陆地生物圈碳库大小的变化，并对生物地球化学对未来变暖的反馈反应施加限制。大气中的氦-3/氦-4记录将检验这样一种假设，即在4.1万年前发生的被称为拉尚事件的地磁场崩溃期间，太阳风(高度浓缩的氦-3)直接凝聚到地球上的S大气中。在回收冰芯后，逃逸气体样本将由PI和一名博士后学者在一个支持重复取心和加深井眼的现有项目的保护伞下立即现场采集。这项工作将在不增加后勤资源额外费用的情况下，为实地工作活动的科学回报增加价值。这项工作对大气氧气的更广泛影响是，它可能增加对陆地碳库和大气温室气体源将如何对即将到来的气候变暖做出反馈的理解。大气氧的长期趋势对于理解生物地球化学调控机制和大气演化对生命的影响也很有意义。氦记录对于了解这种不可再生气体的预算及其对空间天气和太阳活动的影响很有价值。该项目将培养一名研究生和一名博士后学者。将固体地球、冰冻圈、大气层和空间天气联系起来的魅力将有助于吸引和激发年轻科学家，将地球作为一个相互关联的系统来理解的努力将为所有年龄段的外展工作提供燃料。

1143619/SeveringhausThis award supports a project to extend the study of gases in ice cores to those gases whose small molecular diameters cause them to escape rapidly from ice samples (the so-called "fugitive gases"). The work will employ helium, neon, argon, and oxygen measurements in the WAIS Divide ice core to better understand the mechanism of the gas close-off fractionation that occurs while air bubbles are incorporated into ice. The intellectual merit of the proposed work is that corrections for this fractionation using neon (which is constant in the atmosphere) may ultimately enable the first ice core-based atmospheric oxygen and helium records. Neon may also illuminate the mechanistic link between local insolation and oxygen used for astronomical dating of ice cores. Helium measure-ments in the deepest ~100 m of the core will also shed light on the stratigraphic integrity of the basal ice, and serve as a probe of solid earth-ice interaction at the base of the West Antarctic ice sheet. Past atmospheric oxygen records, currently unavailable prior to 1989 CE, would reveal changes in the size of the terrestrial biosphere carbon pool that accompany climate variations and place constraints on the biogeochemical feedback response to future warming. An atmospheric helium-3/helium-4 record would test the hypothesis that the solar wind (which is highly enriched in helium-3) condensed directly into Earth?s atmosphere during the collapse of the geomagnetic field that occurred 41,000 years ago, known as the Laschamp Event. Fugitive-gas samples will be taken on-site immediately after recovery of the ice core by the PI and one postdoctoral scholar, under the umbrella of an existing project to support replicate coring and borehole deepening. This work will add value to the scientific return from field work activity with little additional cost to logistical resources. The broader impacts of the work on atmospheric oxygen are that it may increase understanding of how terrestrial carbon pools and atmospheric greenhouse gas sources will respond in a feedback sense to the coming warming. Long-term atmospheric oxygen trends are also of interest for understanding biogeochemical regulatory mechanisms and the impact of atmospheric evolution on life. Helium records have value in understanding the budget of this non-renewable gas and its implications for space weather and solar activity. The project will train one graduate student and one postdoctoral scholar. The fascination of linking solid earth, cryosphere, atmosphere, and space weather will help to entrain and excite young scientists and efforts to understand the Earth as a whole interlinked system will provide fuel to outreach efforts at all ages.