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

合作研究：泰勒冰川、南极洲、水平冰芯：探索变暖世界中自然甲烷预算的变化并扩大古档案

• 批准号: 1245659
• 负责人: Vasilii Petrenko
• 金额: $ 52万
• 依托单位: University of Rochester
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-08-01 至 2018-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1245659&HistoricalAwards=false
• 关键词: Collaborative; Research; Taylor; Glacier; Antarctica

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.

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本以进行一系列古环境研究的项目。将获得最后一次冰消期和全新世早期的大气甲烷碳14（14CH4）记录，以及CH4稳定同位素的支持记录。将以前所未有的精度在从表面至约 67 m 的冰中测定原位宇宙成因 14C 含量以及不同物种（14CH4、C-14 一氧化碳 (14CO) 和 C-14 二氧化碳 (14CO2)）之间 14C 的分配。将使用 CH4、CO2、氧气的 18O 和 H2O 稳定同位素的组合来对消融冰地层进行进一步的年龄测绘。获得末次冰消期和末次冰期间隔的高精度、高分辨率的CO2、CO2~13C、一氧化二氮（N2O）和N2O同位素的记录。将研究 14CO2 和 Krypton-81 (81Kr) 作为冰川冰绝对测年工具的潜力。拟议工作的智力价值包括以下事实：天然甲烷源对全球持续变暖的反应是不确定的，并且现有证据不足以排除大型 14C 贫化库（例如 CH4 包合物和永久冻土）发生灾难性释放的可能性。拟议的古大气 14CH4 记录将提高我们对大规模气候变暖期间这些水库中 CH4 释放的可能程度和时间的了解。目前还缺乏对冰川中原位宇宙生成 14C（不同机制的生产速率和物种之间的分配）的透彻了解。这种理解可能会使得在积聚地点的冰中使用原位 14CO 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，以及在冰积聚和冰消融中使用 14CO2网站作为绝对的约会工具。我们对自然碳循环及其对全球气候变化的反应的理解仍然存在重大差距。拟议的 13C CO2 高分辨率、高精度记录将提供有关碳循环变化的新信息，无论是在气候变暖时二氧化碳上升的时期还是在气候变冷时二氧化碳下降的时期。 N2O 是一种重要的温室气体，在末次冰消期期间增加了约 30%。这种增加的原因在很大程度上仍不确定，拟议的 N2O 浓度和同位素高精度记录将有助于进一步了解变暖世界中 N2O 来源的变化。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。泰勒冰川消融冰的持续年龄测绘将为这一高质量、易于获取的自然环境变化档案增加价值。将 14CO 建立为过去宇宙射线通量的强大新示踪剂将为古气候研究提供信息，并对气候变化这一社会重要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。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。 UR、OSU 和 SIO 各培养 1 名研究生，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。这项工作将为UR的新任初级教员Petrenko提供支持。所有 PI 都拥有通过媒体采访、参与实地项目拍摄以及向学校和公众讲述其研究等形式进行科学推广的悠久历史和承诺，并将继续将这些活动作为拟议工作的一部分。 该奖项在南极洲进行了实地考察。