Optical Logging for Dust and Microbes in Boreholes in Glacial Ice

该奖项支持使用新开发的光学钻孔记录仪在气候学、地球科学和极端环境中的生命方面进行研究。该记录仪适合在冰川冰中充满流体的钻孔中。它在水平面上发射370 nm的光，以便探测离钻孔几米远的冰层中嵌入的颗粒的光学性质。离开井眼后，光线被灰尘、生物分子或微生物部分吸收和散射。一部分光被散射回钻孔，并被一个由七个光管组成的系统探测到，每个光管在单独的波长波段以高效率收集光。其中一个收集从尘埃和气泡中散射出来的光，而不会发生波长变化，并充当尘埃记录器。其他六个覆盖着陷波滤光片，测量六个不同的波长带，并测量微生物和生物分子的荧光光谱的形状。因此，同一台仪器既可用作灰尘记录器，又可用作微生物记录器。应用包括：1)精确的年表和长周期的太阳变化。GISP2和Siple Dome的分辨率都为1到2厘米，记录仪将记录每年的尘埃最大值，并评估尘埃浓度调制的声称，周期从11年(太阳周期)到2300年；2)火山作用和年龄深度标记。数十个火山灰带将被探测到，并将作为其他钻孔的主要年龄深度标志；3)微生物和生物分子。可以记录活的、休眠的和死亡的微生物的垂直分布，并可以搜索古生菌和风成多芳烃。测井实验将在南极洲的Siple Dome和Dome C以及格陵兰的GISP2和GRIP进行。

0125794PriceThis award supports research in climatology, geosciences, and life in extreme environments to be carried out with a newly developed optical borehole logger. The logger fits into a fluid-filled borehole in glacial ice. It emits light at 370 nm in a horizontal plane in order to probe optical properties of particles embedded in the ice out to several meters from the borehole. After leaving the borehole, the light is partially absorbed and scattered by dust, biomolecules, or microbes. A fraction of the light is scattered back into the borehole and is detected by a system of seven phototubes, each of which collects light with high efficiency in a separate wavelength band. One of them collects light that scatters off of dust and air bubbles without wavelength shift, and serves as a dust logger. The other six are covered with notch filters that measure six different wavelength bands and measure the shape of the fluorescence spectrum of microbes and biomolecules. Thus, the same instrument serves as both a dust logger and a microbe logger. Applications include: 1) Precise chronologies and long-period solar variability. With a resolution of 1 to 2 cm for both GISP2 and Siple Dome, the logger will record annual dust maxima and evaluate claims of modulations of dust concentration with periods ranging from 11 yrs (the solar cycle) to 2300 yrs; 2) Volcanism and age-depth markers. Dozens of volcanic ash bands will be detectable and will serve as primary age-depth markers for other boreholes; 3) Microorganisms and biomolecules. The vertical distribution of living, dormant, and dead microbes can be logged, and searches for archaea and aeolian polyaromatic hydrocarbons can be made. The logging experiments will be carried out at Siple Dome and Dome C in Antarctica and at GISP2 and GRIP in Greenland.