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方半球夏季月份东非夏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变化，西风带提供的降水量可能在过去也相当高。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。通过评估和应用这种生物标志物和稳定同位素工具，该项目旨在促进（半）定量重建的古气候/水文历史的Bale山脉，埃塞俄比亚。具体而言，应重建温度、空气相对湿度和降水来源和数量。一个工作包将侧重于现代降水的空间和时间/季节同位素特征（2 H/1H和18 O/16 O）。所获得的数据将有助于提高对现代大气环流模式的理解，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如何准确地印在植物和土壤的生物标志物和稳定同位素组成上。这将通过研究巴莱山脉的气候和海拔剖面来实现。方法的重点将放在化合物特定的2 H-分析叶蜡衍生的正烷烃和脂肪酸生物标志物，化合物特定的18 O-分析半纤维素衍生的糖生物标志物和土壤细菌衍生的甘油二烷基甘油四醚（GDGT）脂质生物标志物。第三个工作包有助于检索沉积物岩心和建立年代地层学。这些岩心将与子项目P2-人为土壤和P4-古生态学联合调查，作为重建人类占领历史以及Bale山脉晚第四纪古环境/气候/水文历史的档案。因此，上述生物标志物和稳定同位素技术将应用于该子项目。