Collaborative Research: Investigating the Rate of Potential Biological in Situ Gas Production of CO and CH4 in Arctic Ice

合作研究：研究北极冰中 CO 和 CH4 的潜在生物原位产气率

• 批准号: 2139294
• 负责人: Christopher Carr
• 金额: $ 6.29万
• 依托单位: Georgia Tech Research Corporation
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-03-01 至 2025-02-28
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2139294&HistoricalAwards=false
• 关键词: Collaborative; Research; Investigating; Rate; Potential

Atmospheric gas records developed from polar ice cores are cornerstones of climate change science. The overarching goal of this project is to develop and apply new understanding of high-time-resolution Arctic records of methane and carbon monoxide. Methane is a powerful greenhouse gas and carbon monoxide is linked to the atmospheric lifetime of other greenhouse gases including carbon dioxide. Thus, developing reliable records of both gases is important for understanding past and future atmospheric chemistry and radiative forcing. High-depth-resolution records of carbon monoxide, and to a lesser extent methane, in Arctic ice cores show evidence of non-atmospheric anomalies that are poorly understood. One potential source of such anomalies is biological activity within the ice. Microbes can be active at temperatures well below freezing, and ice cores are subjected to relatively warm temperatures after the ice is extracted from glaciers and ice sheets while they are stored or transported prior to measurement. Special sample handling protocols will be used to evaluate the effects of post-collection ice temperature on methane and carbon monoxide production, and potentially allow development of methane and carbon monoxide records over recent centuries that are free from any artifacts. Funding will support early career investigators, graduate students and undergraduate students who will be involved in field work, laboratory analysis, and data interpretation. The investigators will involve undergraduates from underrepresented groups to foster diversity in earth sciences. Public outreach will be achieved through public lectures, lab tours, and media interactions. The specific goals of this project are to (1) investigate the rate and timing of temperature-dependent in situ biological production of carbon monoxide and methane in an Arctic ice core, (2) develop records of atmospheric carbon monoxide and methane spanning recent centuries that are free of in situ production artifacts, and (3) determine the roles that ice impurity concentration and microbial community structure play in situ gas production. To accomplish these goals, a 150-meter ice core will be collected at Summit, Greenland using the large-diameter Blue Ice Drill. To address goal (1), successive measurements of carbon monoxide and methane will be made in the field on eight parallel longitudinal samples from a 12 meter-long section of the core, with the different samples consistently stored and monitored at temperatures ranging from well below the -31 °C ice sheet temperature at Summit to well above the -26 °C cell vitrification temperature where cellular metabolism is possible. For goal (2), measurements of these two gases will be made in the field on ice that has been kept consistently at -40 °C after extraction. For goal (3), a portion of the entire ice core will be returned to the U.S. for microbial analyses, measurements of a range of elements and chemical species using a well-established, NSF-funded continuous ice core analytical system, and continuous carbon monoxide and methane measurements to complement the field measurements. Microbiological analysis will be conducted on ice samples characterized by high and low in situ gas anomalies to determine what microbes are present that may be responsible for creating the observed gas artifacts.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

极地冰芯形成的大气气体记录是气候变化科学的基石。该项目的首要目标是发展和应用对高时间分辨率的北极甲烷和一氧化碳记录的新理解。甲烷是一种强大的温室气体，一氧化碳与包括二氧化碳在内的其他温室气体的大气寿命有关。因此，开发这两种气体的可靠记录对于了解过去和未来的大气化学和辐射强迫非常重要。北极冰芯中一氧化碳和甲烷的高深度分辨率记录显示了人们对其知之甚少的非大气异常的证据。这种异常的一个潜在来源是冰层内的生物活动。微生物可以在远低于冰点的温度下活动，冰芯在测量之前储存或运输冰块时，从冰川和冰盖中提取冰后，会受到相对温暖的温度。将使用特殊的样本处理协议来评估采集后冰温对甲烷和一氧化碳产生的影响，并可能允许开发近几个世纪没有任何人工制品的甲烷和一氧化碳记录。资金将支持早期职业调查人员、研究生和本科生，他们将参与实地工作、实验室分析和数据解释。调查人员将包括来自代表性不足群体的本科生，以促进地球科学的多样性。将通过公开讲座、实验室参观和媒体互动来实现公众宣传。该项目的具体目标是：(1)调查北极冰芯中一氧化碳和甲烷的随温度变化的就地生物产生的速率和时间；(2)建立近几个世纪以来没有就地产生人工产物的大气一氧化碳和甲烷的记录；(3)确定冰杂质浓度和微生物群落结构在就地制气中所起的作用。为了实现这些目标，格陵兰岛顶峰将使用大直径蓝色冰钻收集150米长的冰芯。为了实现目标(1)，将在实地对来自岩心12米长部分的8个平行的纵向样本进行一氧化碳和甲烷的连续测量，不同的样本将在远低于顶峰冰盖温度-31摄氏度到远高于细胞新陈代谢的-26摄氏度玻璃化温度的温度范围内持续存储和监测。对于目标(2)，这两种气体的测量将在野外冰上进行，冰在提取后一直保持在-40°C。对于目标(3)，整个冰芯的一部分将被送回美国进行微生物分析，使用NSF资助的成熟的连续冰芯分析系统测量一系列元素和化学物种，并进行连续的一氧化碳和甲烷测量，以补充现场测量。将对具有高和低原位气体异常特征的冰样进行微生物分析，以确定存在哪些微生物可能导致观察到的气体人工制品的产生。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。