Doctoral Dissertation Research: Holocene Climate and Environmental Change in the Great Basin of the Western United States: A Paleolimnological Approach

Ohio State University, The, Columbus OH

Investigators

Abstract

Recent research in the Great Basin has demonstrated the need for quantitative, high-resolution temperature reconstructions that extend understanding of past thermal regimes further into the last 10,000 years. This doctoral dissertation research will assess recent environmental change and human-related influences on a suite of lakes in the central Great Basin, and it will develop high-resolution temperature reconstructions spanning the past 8,000 years, with an emphasis on the two most recent warm intervals, the Medieval Climate Anomaly and the Holocene Thermal Maximum. The doctoral student will gather data from a network of sites will be collected in the central Great Basin and analyze these materials in search of signals of past climatic changes. Lake sediments collected from this network will be measured for a variety of physical and biological indicators to include sub-fossil chironomids, sediment organic content, biogenic silica, mercury concentration, spheroidal carbonaceous particles, grain size, and macroscopic charcoal. These indicators will be used to characterize the recent temperature changes and pollution loadings along with long-term changes to productivity, temperatures, and fire histories in the region. Accurate chronological control will be ensured through lead-210 dating the recent sediment and accelerator mass spectrometer radiocarbon dates on sedimentary charcoal and identifiable plant remains. The results from the research will be compared with other paleoclimate reconstructions to gain a better understanding of the spatial and temporal climatic changes in the Great Basin. The results of this project will facilitate a more thorough examination of the influence of temperature on effective moisture and aridity in the Great Basin over the past 8,000 years. This will further contribute to basic understanding of the response of aquatic ecosystems to past and possibly future environmental change. Project results also should help identify how various human-related factors have influenced the structure and composition of these lakes during the most recent centuries. An ever-increasing supply of freshwater is required for the urban areas in the Great Basin, which have experienced dramatic population growth in recent decades. This research will help understand the long-term natural variability of thermal and moisture regimes for this region. The project also should help enhance decision making with regard to water policy and assist in adaptations to future climate variability and change. As a Doctoral Dissertation Research Improvement award, this award also will provide support to enable a promising student to establish a strong independent research career.