Continuous Holocene Climate Records from Equatorial Pacific Islands

来自赤道太平洋岛屿的连续全新世气候记录PI将产生跨越过去10,000年的赤道太平洋气候变化的连续、高分辨率记录。将在帕劳、基里巴斯和加拉帕戈斯的淡水、咸水和高盐度湖泊中测量一套新开发的分子和同位素降雨指标，以重建全新世期间厄尔尼诺南方涛动(ENSO)的变化。由于H2O的蒸汽压高于HDO，闭合盆地和高盐度湖泊中的氢同位素比值是降水和蒸发平衡的敏感指标。之前在PIS实验室进行的实验研究表明，藻类类脂D/H比率是环境水D/H比率近乎完美的记录器。因此，通过在湖泊和高含盐盆地的沉积物岩心中进行类脂D/H测量，有可能产生连续的水文变化记录。帕劳、基里巴斯和加拉帕戈斯的水文变化的连贯模式，例如在现代厄尔尼诺事件期间观察到的模式，将坚定地支持ENSO的变化和过去热带太平洋气候的平均状态。这项研究将促进教师、学生、政府和非政府机构以及来自热带太平洋广泛不同发展中国家的居民之间的动态互动。评估热带太平洋气候的历史和敏感性具有重大的社会意义，因为全球70%的人口生活在热带地区，厄尔尼诺期间的洪水和干旱加剧了本已紧张的水资源。该项目将涉及研究生、一名博士后研究员和现场和实验室研究的本科生助理。

0602170AbstractSachsContinuous Holocene Climate Records from Equatorial Pacific IslandsThe PI will produce continuous, highly resolved records of climate change across the equatorial Pacific that span the last 10,000 years. A newly developed suite of molecular and isotopic indicators of rainfall will be measured in well-dated, rapidly accumulating sediments from freshwater, saline and hypersaline lakes in Palau, Kiribati and the Galapagos to reconstruct El Nino Southern Oscillation (ENSO) variations during the Holocene. Owing to the higher vapor pressure of H2O relative to HDO, hydrogen isotopic ratios in closed basin and hypersaline lakes are sensitive indicators of the balance between precipitation and evaporation. Prior experimental studies performed in the PIs laboratory demonstrated that algal lipid D/H ratios are near-perfect recorders of environmental water D/H ratios. Thus, by conducting lipid D/H measurements in sediment cores from lakes and hypersaline basins, it is possible to produce a continuous record of hydrologic changes. Coherent patterns of hydrologic change in Palau, Kiribati and the Galapagos, such as those observed during modern El Nino events, would firmly support changes in ENSO and the mean state of tropical Pacific climate in the past.This research will foster dynamic interactions between faculty, students, government and non-government institutions, and residents from a wide diversity of developing nations spanning the tropical Pacific. Evaluating the history and sensitivity of the tropical Pacific climate is of great societal relevance because 70% of global population lives in the tropics where flood and drought during El Nino exacerbate already-strained water resources. This project will involve graduate students, a post-doctoral researcher and undergraduate assistants in the field and laboratory research.