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，将冰芯中气体的研究扩展到那些分子直径小，导致它们迅速从冰样品中逃逸的气体（所谓的“逃逸气体”）。 这项工作将采用氦，氖，氩和氧测量WAIS分水岭冰芯，以更好地了解气体封闭分馏的机制，而气泡被纳入冰。 这项工作的智力价值在于，使用氖（在大气中是恒定的）对这种分馏进行校正，最终可能会使第一个基于冰芯的大气氧和氦记录成为可能。氖也可能阐明当地日照和用于冰芯天文定年的氧气之间的机械联系。在冰芯最深~100 m处进行的氦测量也将揭示底冰的地层完整性，并作为西南极冰盖底部固体地球-冰相互作用的探测器。 过去的大气氧记录，目前无法在1989 CE之前，将揭示陆地生物圈碳库的大小变化，伴随着气候变化和地方的地球化学反馈响应未来变暖的限制。大气中氦-3/氦-4的记录将检验太阳风（高度富集氦-3）直接凝结到地球上的假设？在41，000年前发生的地磁场崩溃期间，被称为Laschamp事件。 在现有项目的保护下，PI和一名博士后学者将在冰芯回收后立即现场采集散逸气体样本，以支持重复取芯和钻孔加深。这项工作将增加野外工作活动的科学回报的价值，而后勤资源的额外费用很少。 这项工作对大气氧的更广泛影响是，它可能会增加对陆地碳库和大气温室气体源如何在反馈意义上对即将到来的变暖作出反应的理解。长期的大气氧趋势对于理解地球化学调节机制和大气演变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收支及其对空间天气和太阳活动的影响具有价值。 该项目将培养一名研究生和一名博士后。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，而将地球作为一个整体相互关联的系统来理解的努力将为所有年龄段的外联工作提供动力。

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.