MRI: Acquisition of a Cavity Ring-Down Spectrometer for Analyzing Stable Isotopes in Water Samples at Middlebury College

该重大研究仪器（MRI）计划奖支持获得用于分析水样中氧稳定同位素的腔衰荡光谱仪（CRDS）。CRDS将支持米德尔伯里学院地质系的研究和研究培训。授予机构。本科生在这个非博士-授予机构将使用CRDS进行所需的高级论文的体验式学习。 总的来说，地质系通常提供约300个座位/年在各级班级，预计这些学生中的大多数将有机会在他们的课程和研究中使用这种仪器。CRDS还将为来自周边机构的同事和学生提供服务，他们将被邀请来米德尔伯里进行分析，作为他们自己研究的一部分。因此，在Middlebury购买用于分析水同位素的CRDS将为该地区的本科生提供重要的学习机会和实践研究培训。该仪器将广泛用于地质学系Jeffrey Munroe和Peter Ryan博士的研究项目。CRDS促进的研究将包括：调查全新世古气候，如记录在多年洞穴冰沉积物的稳定氧和同位素中;研究岩石冰川作为高山景观的地表水资源;岩溶过程;以及研究裂缝地下含水层中有害化合物的运输和归宿。门罗正在积极研究稳定同位素组成和常年洞穴冰沉积物的冰川化学，以发展全新世古气候记录，正在调查岩石冰川作为高山景观地表水来源的重要性，以及融化的常年冰对岩石冰川流出的贡献，并正在努力从洞穴洞穴沉积物的稳定同位素中发展长期的古气候记录。正确解释这些记录需要有关现代降水和洞穴中滴水的稳定同位素组成的信息。该系统将用于分析最近使用的自动滴水采样器收集的水样本。Ryan是一位低温地球化学家，他将在佛蒙特州的含水层补给、流动和排放的各种研究中使用该仪器，因为它涉及到渗透和成分。Ryan和本科生合作者调查了断裂岩石含水层中地质砷的来源，评估了富含铀的碳酸盐含水层的异质性，并考虑了农业和工业污染物的运输和命运。获得CRDS将是所有这些项目向前迈出的重要一步，它允许测量水中的稳定同位素，并促进其作为地下水流示踪剂的使用。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This Major Research Instrumentation (MRI) Program award supports acquisition of a cavity ring-down spectrometer (CRDS) for analysis of stable isotopes of oxygen in water samples. The CRDS will support research and research training in the Geology Department at Middlebury College, a non-Ph.D. granting institution. Undergraduate students at this non-Ph.D.-granting institution will be engaged in experiential learning using the CRDS for required senior theses. In total, the Geology Department typically offers ~300 seats/year in classes at all levels, and it is expected that the majority of these students will have the opportunity to use this instrument during their coursework and research. The CRDS will also serve colleagues and their students from surrounding institutions who will be invited to come to Middlebury to make analyses as part of their own research. Acquisition of a CRDS for analyzing water isotopes at Middlebury will, therefore, catalyze significant learning opportunities and hands-on research training for undergraduate students in this region.The instrument will be used extensively in the research programs of Drs. Jeffrey Munroe and Peter Ryan in the Department of Geology. Research to be facilitated by the CRDS will include: investigations of Holocene paleoclimate as recorded in in the stable oxygen and isotopes of perennial cave ice deposits; studies of rock glaciers as surface water resources in alpine landscapes; karst processes; and studies of the transport and fate of deleterious compounds in fractured groundwater aquifers. Munroe is actively studying the stable isotopic composition and glaciochemistry of perennial cave ice deposits in order to develop Holocene paleoclimate records, is investigating the significance of rock glaciers as sources of surface water in alpine landscapes, and the contribution of melting perennial ice to rock glacier outflow, and is working to develop a long-term paleoclimate records from stable isotopes in cave speleothems. Properly interpreting these records requires information about the stable isotopic composition of modern precipitation and dripwater in the caves with the speleothems were collected. The CRDS will be used in analyzing water samples collected with a recently deployed automatic drip water sampler. Ryan is low-temperature geochemist who will use the instrument in a variety of studies of aquifer recharge, flow and discharge in Vermont, as it relates to transmissivity and composition. Ryan and undergraduate student collaborators have investigated the sources of geogenic arsenic in fractured rock aquifers, evaluated heterogeneity in a uranium-rich carbonate aquifer, and considered the transport and fate of agricultural and industrial contaminants. Acquisition of a CRDS will be a major step forward for all of these projects, allowing measurements of stable isotopes in water and facilitating their use as tracers of groundwater flow.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.