Collaborative Research: The Taylor Glacier, Antarctica, Horizontal Ice Core: Exploring changes in the Natural Methane Budget in a Warming World and Expanding the Paleo-archive

1245659/Petrenko该奖项支持一个项目，该项目利用南极洲泰勒冰川消融带收集冰样，用于一系列古环境研究。将获得最后一次冰川消融和全新世早期大气甲烷(14CH4)的碳-14记录，以及CH4稳定同位素的支持记录。从地表到67米的冰层中，将以前所未有的精度测定宇宙成因的14C含量和14C在不同物种(14CH4、C-14一氧化碳(14CO)和C-14二氧化碳(14CO2))之间的分配。进一步的消融冰层年龄填图将使用CH4、CO2和氧气和H2O稳定同位素的组合进行。高精度、高分辨率的二氧化碳、一氧化二氮(N2O)和一氧化二氮(N2O)同位素记录将在最后一次冰川消融期间和最后一次冰期期间获得。14CO2和氪-81(81Kr)作为冰川冰的绝对测年工具的潜力将被调查。拟议工作的学术价值包括这样一个事实，即天然甲烷源对持续的全球变暖的反应是不确定的，现有证据不足以排除甲烷笼状化合物和永久冻土等耗尽14C的大型水库灾难性释放的可能性。拟议的古大气14CH4记录将提高我们对这些水库在大规模气候变暖期间释放CH4的可能规模和时间的理解。目前尚缺乏对冰川冰中原位宇宙成因14C(不同机制和物种间分配的产生率)的透彻了解。这样的理解可能会使在聚集点的冰中原位14CO用作过去宇宙射线流量和可能过去的太阳活动的可靠、简单的示踪剂，以及在冰聚集和冰消融地点使用14CO2作为绝对测年工具。在我们对自然碳循环及其对全球气候变化的反应方面，仍然存在重大差距。拟议的高分辨率、高精度的二氧化碳13C记录将提供有关气候变暖时二氧化碳上升和气候变冷时二氧化碳下降期间碳循环变化的新信息。N2O是一种重要的温室气体，在最后一次冰川消融期间增加了约30%。这种增加的原因在很大程度上仍然不确定，拟议的N2O浓度和同位素的高精度记录将提供对全球变暖中N2O来源变化的进一步洞察。拟议工作的更广泛影响包括改善我们对这些温室气体预算对全球变暖的反应的理解，并为未来气候变化的具有社会重要性的模型预测提供信息。继续绘制泰勒冰川消融冰的年龄图将为这份高质量、易于获取的自然环境变异性档案增添价值。建立14CO作为过去宇宙射线通量的强有力的新示踪剂将为古气候研究提供信息，并对气候变化这一具有重要社会意义的问题的研究做出宝贵贡献。拟议的工作将有助于开发新的实验室和现场分析系统。这项研究的数据将通过NSIDC和NOAA古气候学数据中心提供给科学界和广大公众。每名研究生将在俄勒冈大学、俄勒冈州立大学和SIO接受培训，这项工作将有助于在俄勒冈州州立大学培养一名博士后。3 UR本科生将参与实地考察和研究。这项工作将支持UR的一名新的初级教职员工Petrenko。所有私人投资机构都有通过媒体采访、参与实地项目拍摄以及向学校和公众介绍其研究情况等形式开展科学宣传的良好历史和承诺，并将继续开展这些活动，作为拟议工作的一部分。这一奖项在南极洲进行了实地考察。

1245659/PetrenkoThis award supports a project to use the Taylor Glacier, Antarctica, ablation zone to collect ice samples for a range of paleoenvironmental studies. A record of carbon-14 of atmospheric methane (14CH4) will be obtained for the last deglaciation and the Early Holocene, together with a supporting record of CH4 stable isotopes. In-situ cosmogenic 14C content and partitioning of 14C between different species (14CH4, C-14 carbon monoxide (14CO) and C-14 carbon dioxide (14CO2)) will be determined with unprecedented precision in ice from the surface down to ~67 m. Further age-mapping of the ablating ice stratigraphy will take place using a combination of CH4, CO2, δ18O of oxygen gas and H2O stable isotopes. High precision, high-resolution records of CO2, δ13C of CO2, nitrous oxide (N2O) and N2O isotopes will be obtained for the last deglaciation and intervals during the last glacial period. The potential of 14CO2 and Krypton-81 (81Kr) as absolute dating tools for glacial ice will be investigated. The intellectual merit of proposed work includes the fact that the response of natural methane sources to continuing global warming is uncertain, and available evidence is insufficient to rule out the possibility of catastrophic releases from large 14C-depleted reservoirs such as CH4 clathrates and permafrost. The proposed paleoatmospheric 14CH4 record will improve our understanding of the possible magnitude and timing of CH4 release from these reservoirs during a large climatic warming. A thorough understanding of in-situ cosmogenic 14C in glacial ice (production rates by different mechanisms and partitioning between species) is currently lacking. Such an understanding will likely enable the use of in-situ 14CO in ice at accumulation sites as a reliable, uncomplicated tracer of the past cosmic ray flux and possibly past solar activity, as well as the use of 14CO2 at both ice accumulation and ice ablation sites as an absolute dating tool. Significant gaps remain in our understanding of the natural carbon cycle, as well as in its responses to global climate change. The proposed high-resolution, high-precision records of δ13C of CO2 would provide new information on carbon cycle changes both during times of rising CO2 in a warming climate and falling CO2 in a cooling climate. N2O is an important greenhouse gas that increased by ~30% during the last deglaciation. The causes of this increase are still largely uncertain, and the proposed high-precision record of N2O concentration and isotopes would provide further insights into N2O source changes in a warming world. The broader impacts of proposed work include an improvement in our understanding of the response of these greenhouse gas budgets to global warming and inform societally important model projections of future climate change. The continued age-mapping of Taylor Glacier ablation ice will add value to this high-quality, easily accessible archive of natural environmental variability. Establishing 14CO as a robust new tracer for past cosmic ray flux would inform paleoclimate studies and constitute a valuable contribution to the study of the societally important issue of climate change. The proposed work will contribute to the development of new laboratory and field analytical systems. The data from the study will be made available to the scientific community and the broad public through the NSIDC and NOAA Paleoclimatology data centers. 1 graduate student each will be trained at UR, OSU and SIO, and the work will contribute to the training of a postdoc at OSU. 3 UR undergraduates will be involved in fieldwork and research. The work will support a new, junior UR faculty member, Petrenko. All PIs have a strong history of and commitment to scientific outreach in the forms of media interviews, participation in filming of field projects, as well as speaking to schools and the public about their research, and will continue these activities as part of the proposed work. This award has field work in Antarctica.