Terrestrial ecosystem and climate dynamics during the Paleocene–Eocene Thermal Maximum (~56 Ma) in the high southern latitudes: An integrated palynological/ organic geochemical study of the Margaret Point section, Southern Australia

由于人为排放，如果排放继续不减，大气中的二氧化碳浓度可能在2300年左右达到1800 ppmv。地球历史上最后一次出现如此极端的二氧化碳浓度是在古新世晚期到始新世早期（约公元前200年）。60-50 Ma前），特别是在几个短暂的高温，打断了这个温室间隔。在这些高温过程中的快速变暖和高碳输入与今天的人为碳释放及其气候后果类似。在这些高温中，古新世-始新世热最大值（PETM; c。#25656;引起了特别的关注。它的特征是向海洋-大气系统中大量注入同位素轻碳，是当前气候变化的一个很好的古模拟，而有关PETM对陆地生态系统影响的信息主要来自北方半球中纬度地区。对于南半球，它仅限于来自新西兰和塔斯马尼亚附近的大洋钻探计划1172号站点的花粉数据。由于这些数据不仅是有限的时间分辨率，但也不能完全代表PETM引起的植被变化在高纬度南半球，有必要从这些纬度额外的，时间上高度分辨率的代理数据。因此，本项目旨在通过分析维多利亚玛格丽特角（古纬度：c. 60 ° S）。因为博士职位的资金已经被授予，否则，这里只要求学生助手，消费品和旅行的资金。广泛的试点工作表明，玛格丽特点部分包含了PETM的开始，并延伸到身体的碳同位素漂移（CIE）。孢子形态的数据将允许建立一个详细的，时间上高分辨率的植被记录，最新的古新世以及到PETM CIE。基于孢子形态的定量气候估计将有助于确定当地PETM变暖的幅度。将孢粉学数据与合作伙伴提供的有机地球化学（MBT-CBT）温度数据和国际照明委员会（CIE）进行比较，将有助于确定碳循环扰动、植被变化和温度变化之间的相位关系。将为玛格丽特角部分生成的数据不仅将使人们对高纬度陆地生态系统对极热断层运动引起的气候变化的反应有前所未有的深入了解，而且还将有助于促进对陆地生态系统对温室气体浓度和温度大幅增加的长期反应的普遍了解。

Due to anthropogenic emissions, atmospheric CO2 concentrations may reach 1800 ppmv around the year 2300 should emissions continue unabated. The last time in Earth’s history when such extreme CO2 concentrations prevailed was the late Paleocene to early Eocene (c. 60-50 Ma ago), and particularly during the several transient hyperthermals that punctuated this greenhouse interval. The rapid warming and high carbon input during these hyperthermals bear analogies to today’s anthropogenic carbon release and its climatic consequences. Among these hyperthermals, the Paleocene-Eocene Thermal Maximum (PETM; c. 56 Ma) has reached particular attention. Characterized by a massive injection of isotopically light carbon into the ocean-atmosphere system, it represents an excellent paleoanalog for present climate change as a result of excess carbon emissions.Information on the consequences of the PETM for terrestrial ecosystems is yet mainly from the mid-latitudes of the Northern Hemisphere. For the Southern Hemisphere, it is restricted to pollen data from New Zealand and Ocean Drilling Program Site 1172 off Tasmania. Because these data are not only of limited temporal resolution, but also not fully representative of PETM-induced vegetation change in the high-latitude Southern Hemisphere, there is a need for additional, temporally highly resolved proxy data from these latitudes. This project therefore aims to reconstruct PETM-induced terrestrial ecosystem dynamics in southern Australia via the analysis of sporomorphs from an outcrop at Point Margaret, Victoria (paleolatitude: c. 60 deg S). Because funding for a PhD position has already been granted otherwise, here only funds for student helpers, consumables and travel are asked for. Extensive pilote work has shown that the Point Margaret section contains the onset of the PETM and extends into the body of the carbon-isotope excursion (CIE). The sporomorph data will allow to establish a detailed, temporally highly resolved vegetation record for the latest Paleocene well into the PETM CIE. Quantitative sporomorph-based climate estimates will allow to determine the magnitude of local PETM warming. Comparison of the palynological data with organic geochemical (MBT-CBT) temperature data that will be provided by collaboration partners, and the CIE will allow to identify the phase relationships between carbon-cycle perturbation, vegetation change and temperature change. The data to be generated for the Point Margaret section will not only yield yield unprecedented insight into the response of terrestrial ecosystems in the high outhern latitudes to PETM-induced climate change; they will also help to advance the general understanding of the long-term reaction of terrestrial ecosystems to major increases in greenhouse-gas concentrations and temperature.