WAIS Divide: Fluorimetry, Dust Logs, Climatology, Glaciology, Volcanology

价格/1142178该奖项支持一个项目，继续测量叶绿素（Chl）和色氨酸（trp）在WAIS分水岭冰下降到3330米，或更深，如果钻探继续低于3330米。将使用一种新型的微生物活/死染色剂来观察这种减少是否与导致强度随深度缓慢下降的微生物的死亡率有关。先前对GISP 2冰的研究表明，核心深处的甲烷浓度比气候变化引起的变化高出一个数量级。先前工作的结论表明，甲烷峰值是由于那些深处的产甲烷菌在冰中冻结时代谢。利用伯克利荧光分光光度计（BFS），将在国家冰芯实验室（NICL）的WAIS分水岭冰上进行测量，以寻找Trp和Chl的异常大峰值，这将通知气体化学家寻找气体异常的确切深度（即，浓度峰值可能与气候无关）。在荧光扫描GISP 2冰在NICL，色氨酸的增加被发现在许多深度，对应的深度与一氧化二氮（N2 O）尖峰。 通过405 nm激光激发的流式细胞术也将用于寻找在~465 nm处的F420自发荧光发射作为产甲烷菌的特征。以前使用光学记录仪进行的测量使圆顶C冰芯中发现的火山灰层比其他方法发现的要多得多。最近的发现是，对一个新钻的钻孔进行测井，直到WAIS分水岭的底部，结果发现了一个分辨率更高的灰尘模式，以及比在旧钻孔中发现的更高浓度的清晰可分辨的火山灰层，这将是一个值得探索的问题。利用这些新的冰芯测井结果，将有可能了解是否有任何灰层与在其他地点发现的火山灰层在时间上吻合，并将加强现有证据，证明大规模火山爆发与表明气候突变的灰尘记录峰值之间存在因果关系。 这项工作的智力价值在于，这些数据将有助于更好地了解促成冰中气体杂质的过程，并有助于更好地了解全球火山活动与气候之间的联系。最后，47个微型倾斜仪安装在冰中的不同深度和横向位置的光学模块中，这些模块被冻结成IceCube阵列。他们已经记录了将近一年的倾斜。这些数据将再分析三年，这将提供一个独特的机会来研究大量寒冷冰川冰的剪切应变率作为剪切应力的函数。这项工作的更广泛影响包括应用于火星探测、古冰生命研究、海洋学、湖沼学、气象学、气候和火山学的可能性。该项目将有助于教育和培训范围广泛的本科生和研究生和博士后从美国。S.等国

Price/1142178This award supports a project to continue the measurements of chlorophyll (Chl) and tryptophan (trp) in WAIS Divide ice down to 3330 m, or deeper if drilling continues below 3330 m. A new type of live/dead stain for microbes will be used to see if the decrease is related to the death rate of microbes responsible for the slow decrease of intensity with depth. Previous work on GISP2 ice has shown that methane concentrations in deeper sections of the core were an order of magnitude higher than the variations due to climate change. The conclusion from the prior work suggested that the methane spikes were due to methanogens at those depths that were metabolizing while frozen in the ice. With the Berkeley Fluorescence Spectrophotometer (BFS) measurements will be made on WAIS Divide ice at the National Ice Core Laboratory (NICL) to look for unusually large spikes of Trp and Chl that will inform gas chemists of the exact depths to look for gas anomalies (i.e., concentration spikes that may not be related to climate). In fluorimetric scanning of GISP2 ice at NICL, increases in Trp were found at many depths, corresponding to depths with nitrous oxide (N2O) spikes. Flow cytometry with excitation by a 405 nm laser will also be used to look for F420 autofluorescence emission at ~465 nm as a signature of methanogens. Previous measurements with the optical logger enabled many more volcanic ash layers to be found in the Dome C ice core than had been found with other methods. The recent discovery that logging of a freshly drilled borehole, to the bottom of WAIS Divide, resulted in a higher-resolution dust pattern and a far greater concentration of clearly resolvable volcanic ash layers than had been found in older boreholes is something that will be explored. Using these new ice core logging results, it will be possible to see if any ash layers coincide in time with volcanic ash layers that have been found at other sites and will strengthen existing evidence for a causal relationship between large volcanic eruptions and spikes in the dust log, indicative of abrupt climate changes. The intellectual merit of the work is that the data will contribute to a better understanding of the processes that contribute to gaseous impurities in the ice and to developing a better understanding of the link between global volcanism and climate. Finally, 47 micro-inclinometers are installed in the ice at various depths and lateral positions in optical modules that are frozen into the IceCube array. They have been recording tilt for nearly a year. These data will be analyzed for an additional three years which will provide an unique opportunity to study the shear-strain rate of a huge volume of cold glacial ice as a function of shear stress. The broader impacts of the work include the possibility of applications to Mars exploration, studies of life in ancient ice, oceanography, limnology, meteorology, climate and volcanology. The project will contribute to the education and training of a broad range of undergraduate and graduate students and post-docs from the U. S. and other countries.