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

最近在大盆地的研究表明，需要定量的、高分辨率的温度重建，以进一步了解过去10000年的热状态。本博士论文研究将评估最近的环境变化和人类活动对中部大盆地一套湖泊的影响，并将开发过去8000年的高分辨率温度重建，重点是最近的两个温暖间隔，中世纪气候异常和全新世热最大值。博士生将从大盆地中部的一个站点网络中收集数据，并分析这些材料，以寻找过去气候变化的信号。从该网络收集的湖泊沉积物将测量各种物理和生物指标，包括亚化石chironomids，沉积物有机质含量，生物成因二氧化硅，汞浓度，球形碳质颗粒，粒度和宏观木炭。这些指标将用于描述该地区近期的温度变化和污染负荷，以及该地区生产力、温度和火灾历史的长期变化。精确的时间控制将通过铅210测定最近沉积物的年代和加速器质谱仪测定沉积木炭和可识别的植物遗骸的放射性碳年代来确保。研究结果将与其他古气候重建结果进行比较，以更好地了解大盆地的时空气候变化。该项目的结果将有助于更彻底地研究过去8000年来温度对大盆地有效水分和干旱的影响。这将有助于进一步了解水生生态系统对过去和可能的未来环境变化的响应。项目结果还应有助于确定最近几个世纪以来各种与人类有关的因素是如何影响这些湖泊的结构和组成的。大盆地的城市地区需要不断增加的淡水供应，近几十年来，这些地区的人口急剧增长。这项研究将有助于了解该地区长期的热力和水分状况的自然变化。该项目还应有助于加强有关水政策的决策，并协助适应未来的气候变率和变化。作为博士论文研究改进奖，该奖项还将提供支持，使有前途的学生建立一个强大的独立研究生涯。

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.