Acquisition of a Stable Isotope Ratio Mass Spectrometer System for Environmental and Paleoclimatic Research

这项拨款支持购置一台稳定同位素比质谱仪（SIRMS），用于明尼苏达大学的环境和古气候研究以及现代生态研究、水文学、湖沼学和水地球化学。将购买一台连续流（CF）质谱仪，该质谱仪带有在线外围设备，可自动制备样品并将纯化气体直接引入离子源，以取代2001年退役的20年历史的Finnigan MAT delta E。CF-SIRMS将减少需要处理的样品的大小，因此允许对样品序列进行更高分辨率的研究，并提高样品吞吐量和精度。将立即受益于所要求的SIMRS能力的研究包括：1)研究美国中部大陆地表水和地下水之间的现代相互作用，这些相互作用记录在湖栖浮游微生物群和动物群遗骸的同位素组成中，以及相关的古记录研究，这些研究对理解中部大陆过去的气候变化具有重要意义；2)湖泊湿地碳平衡研究；3)利用生物源磷灰石化石的稳定同位素分析研究新生代哺乳动物的古饮食，揭示灭绝生物的古环境；4)基于岩洞方解石稳定同位素分析的区域第四纪古气候研究。该仪器还将用于培养来自各个部门的博士后和研究生。为了促进跨学科工作，将每两年举办一次研讨会，教师和学生将讨论他们的研究，重点是同位素分析的作用。参加该大学REU项目的本科生将参与使用新仪器的研究。还将访问印第安人保留地，并就食物网和水文/沉积物循环进行讨论。＊＊＊

0549633ItoThis grant supports acquisition of a stable isotope ratio mass spectrometer (SIRMS) for environmental and paleoclimate research as well as modern ecological studies, hydrology, limnology, and aqueous geochemistry at the University of Minnesota. A continuous flow (CF) mass spectrometer with on-line peripheral devices that prepare samples automatically and introduce the purified gases directly into the ion source will be purchased, replacing a 20-year old Finnigan MAT delta E that was decommissioned in 2001. The CF-SIRMS will reduce the size of samples needed to be processed and therefore allow higher resolution studies of sample sequences to take place and increase sample throughput and precision. Research that will immediately benefit from the capabilities of the requested SIMRS include: 1) studies of modern interactions between surface and groundwaters in the mid-continental U.S. as recorded in the isotopic composition of the remains of lacustrine dwelling planktonic microflora and fauna and related paleorecords studies with implications for understanding past climate variability in the mid-continent; 2) carbon balance investigations in lakes and wetlands; 3) investigations of Cenozoic mammalian paleodiets through stable isotopic analysis of fossil biogenic apatite with implications for elucidating the paleoenvironments of extinct organisms; and 4) regional Quaternary paleoclimate investigations based on stable isotopic analysis of speleothem calcite. The instrument will be also used to train postdocs and graduate students from a variety of departments. To foster interdisciplinary work, a seminar will be offered every two years where faculty and students will talk about their research, focusing on the role of isotope analyses. Undergraduate students participating in the university's REU program will be involved in research that uses the new instrumentation. Indian reservations will also be visited where talks on the food web and hydrologic/sediment cycle will be presented. ***