P5 Paleoclimatology - Stable oxygen (18O/16O) and hydrogen (2H/1H) isotopic composition of plants, soils and rainfall along altitudinal transects, and in paleoclimate archives of the Bale Mountains

P5 古气候学 - 沿海拔样带以及贝尔山脉古气候档案中植物、土壤和降雨的稳定氧 (18O/16O) 和氢 (2H/1H) 同位素组成

• 批准号: 290546751
• 负责人: Professor Dr. Michael Zech
• 金额: --
• 依托单位: Professur für Physische Geographie mit Schwerpunkt Paläoumweltforschung
• 依托单位国家: 德国
• 项目类别: Research Units
• 财政年份: 2016
• 资助国家: 德国
• 起止时间: 2015-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/290546751?language=en
• 关键词: P5; Paleoclimatology; Stable; oxygen; 18O

Ethiopia receives most of its precipitation from southerly winds provided by the East African Summer Monsoon system during Northern Hemispheric summer months. However, the strength of the East African Summer Monsoon varied during the Late Quaternary and the amount of precipitation provided by the westerlies may have been considerably higher in the past as well. During the last decade, certain biomarker and stable isotope techniques emerged as highly innovative and promising tools for (semi-)quantitative paleoclimate/hydrological research. By evaluating and applying such biomarker and stable isotope tools, this project aims at contributing to a (semi-)quantitative reconstruction of the paleoclimate/-hydrological history of the Bale Mountains, Ethiopia. More specifically, temperature, relative air humidity and precipitation source and amount shall be reconstructed.One work package will focus on the spatial and temporal/seasonal isotopic characterisation (2H/1H and 18O/16O) of modern day precipitation. The obtained data shall help to improve the understanding of the modern day atmospheric circulation patterns including their specific isotopic signatures affecting the Bale Mountains. A second work package will evaluate how accurately the isotopic signature of precipitation as well as relative air humidity and temperature are imprinted on the biomarker and stable isotopic composition of plants and soils. This will be achieved by studying climate and altitudinal transects on the Bale Mountains. The methodological focus will lay on compound-specific 2H-analyses of leaf wax-derived n-alkane and fatty acid biomarkers, on compound-specific 18O-analyses of hemicellulose-derived sugar biomarkers and on soil bacteria-derived glycerol dialkyl glycerol tetraether (GDGT) lipid biomarkers. The third work package contributes to the retrieval of sediment cores and the establishment of chronostratigraphies. These cores will be jointly investigated with the subprojects P2-Anthrosols and P4-Paleoecology as archives for the reconstruction of the human occupation history as well as the Late Quaternary paleoenvironmental/climate/hydrological history of the Bale Mountains. The above specified biomarker and stable isotope techniques will therefore be applied within this subproject.

埃塞俄比亚的大部分降水来自北半球夏季东非夏季季风系统提供的南风。然而，东非夏季风的强度在第四纪晚期有所不同，西风带提供的降水量在过去也可能要高得多。在过去的十年中，某些生物标志物和稳定同位素技术成为（半）定量古气候/水文研究的高度创新和有前途的工具。通过评估和应用此类生物标志物和稳定同位素工具，该项目旨在促进（半）定量重建埃塞俄比亚贝尔山脉的古气候/水文历史。更具体地说，应重建温度、相对空气湿度以及降水源和降水量。一个工作包将重点关注现代降水的空间和时间/季节同位素特征（2H/1H 和 18O/16O）。获得的数据将有助于增进对现代大气环流模式的了解，包括影响贝尔山脉的特定同位素特征。第二个工作包将评估降水的同位素特征以及相对空气湿度和温度在植物和土壤的生物标记和稳定同位素组成上的准确程度。这将通过研究贝尔山脉的气候和海拔断面来实现。方法学重点将放在叶蜡衍生的正烷烃和脂肪酸生物标志物的化合物特异性 2H 分析、半纤维素衍生的糖生物标志物的化合物特异性 18O 分析以及土壤细菌衍生的甘油二烷基甘油四醚 (GDGT) 上。 ）脂质生物标志物。第三个工作包有助于沉积物岩心的检索和年代地层的建立。这些核心将与子项目 P2-Anthrosols 和 P4-Paleoecology 联合研究，作为重建人类占领历史以及贝尔山脉晚第四纪古环境/气候/水文历史的档案。因此，上述指定的生物标志物和稳定同位素技术将应用于该子项目。