Dissertation Research: High-resolution Reconstruction of Recent and Late-Holocene Climate Change in Equatorial East Africa

来自热带东非气候敏感的封闭盆地湖泊的晚第四纪沉积物记录证明了千年至千年时间尺度上气候历史的复杂性。由于间接气候效应、湖泊水位和盐度的变化，湖泊对短期气候变化的个体反应使非洲大陆古气候潜在历史的高分辨率重建变得复杂。本论文将通过以下方法提高复杂沉积记录的高分辨率解译：(1)在四个相互关联的湖泊流域系统中对近期气候引起的环境变化进行详细的古湖泊学研究；(2)研究这些浅湖生态系统中湖泊无脊椎动物群落的生态敏感性和物种替代模式；(3)建立湖相无脊椎动物化石组合分析作为高分辨率古气候重建的工具。本论文的研究结果将应用于东非和其他热带地区气候史上一个备受争议但文献记录不足的时期的高分辨率重建：最后一千年，其中可能包括与中世纪温暖期和小冰河期相当的热带时期。我们对小空间尺度气候变化模型的了解，大部分来自于这样的古湖泊学研究。提高气候重建的时间分辨率的尝试对于理解和预测自然短期气候变化背景下的未来气候变化模式将是非常宝贵的。＊＊＊

9320324 Wright Late-Quaternary sediment records from climate sensitive, closed basin lakes in tropical East Africa are testimony to the complexity of climate history at time scales ranging from millennia to years. High resolution reconstruction of the underlying history of African continental paleoclimates is complicated by individualistic response of the lakes to short-term climate change because of variation in indirect climate effects, lake levels, and salinity. This dissertation research will improve high resolution interpretation of complex sedimentary records by (1) conducting a detailed paleolimnological study of recent climate-caused environmental change in a system of four interconnected lake basins, (2) investigating the ecological sensitivity and patterns of species replacement in the lacustrine invertebrate communities of these shallow lake ecosystems, and (3) establishing the analysis of fossil assemblages of these lacustrine invertebrates as a tool in high resolution paleoclimate reconstruction. %%% Results from this dissertation research will be applied to the high resolution reconstruction of a strongly debated but poorly documented episode in climatic history of east Africa and other tropical regions: the last millennium which may include tropical equivalents of the Midieval Warm Epoch and the Little Ice Age. Much of what we know about climate change modeling at small spatial scales derives from paleolimnological studies such as this. The attempts to increase the temporal resolution of climate reconstruction will be invaluable for understanding and predicting future patterns of climate change within the the context of natural, short-term climatic variation. ***