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该奖项支持一个利用南极洲泰勒冰川消融区收集冰样用于一系列古环境研究的项目。将获得末次冰消期和全新世早期大气甲烷（14 CH 4）的碳-14记录，以及CH 4稳定同位素的支持记录。将以前所未有的精度在冰表面下至~67 m处测定原位宇宙成因14 C含量和14 C在不同物种（14 CH 4、C-14一氧化碳（14 CO）和C-14二氧化碳（14 CO2））之间的分配。消融冰地层的进一步年龄测绘将使用甲烷，二氧化碳，#948; 18 O的氧气和H2O稳定同位素的组合。将获得末次冰消期和末次冰期间隔期的CO2、CO2的#948; 13 C、一氧化二氮（N2 O）和N2 O同位素的高精度、高分辨率记录。14 CO2和氪-81（81 Kr）作为冰川绝对定年工具的潜力将被研究。拟议工作的智力价值包括天然甲烷源对持续全球变暖的反应是不确定的，现有证据不足以排除甲烷笼形物和永久冻土等大型14 C耗尽水库发生灾难性释放的可能性。拟议的古大气14 CH 4记录将提高我们的理解可能的规模和时间的CH 4释放从这些水库在一个大的气候变暖。目前缺乏对冰川冰中原位宇宙成因14 C（不同机制的生产率和物种间的分配）的透彻了解。这样的理解将可能使在积累地点的冰中原位使用14 CO作为过去宇宙射线通量和可能过去太阳活动的可靠，简单的示踪剂，以及在冰积累和冰消融地点使用14 CO2作为绝对定年工具。在我们对自然碳循环的理解及其对全球气候变化的反应方面仍然存在重大差距。建议的高分辨率，高精度记录δ 13 C的CO2将提供有关碳循环变化的新信息，无论是在气候变暖时CO2上升还是在气候变冷时CO2下降。N2 O是一种重要的温室气体，在末次冰消期增加了约30%。这种增加的原因在很大程度上仍然不确定，拟议的N2 O浓度和同位素的高精度记录将提供进一步了解N2 O源在变暖的世界中的变化。拟议工作的更广泛影响包括提高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社会重要模型预测提供信息。继续绘制泰勒冰川消融冰的年龄图将增加这一高质量、易于获取的自然环境变化档案的价值。将14 CO确定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，并对研究气候变化的社会重要问题做出宝贵贡献。拟议的工作将有助于开发新的实验室和实地分析系统。该研究的数据将通过NSIDC和NOAA古气候学数据中心提供给科学界和广大公众。1名研究生将分别在UR，OSU和SIO接受培训，这项工作将有助于OSU博士后的培训。3名UR本科生将参与实地考察和研究。这项工作将支持一个新的，初级UR教师，彼得连科。所有PI都有很强的历史和承诺，以媒体采访的形式进行科学宣传，参与实地项目的拍摄，以及向学校和公众介绍他们的研究，并将继续这些活动作为拟议工作的一部分。 这个奖项在南极洲有实地工作。

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.