The development of novel terrestrial palaeoclimate proxies based on 3-hydroxy fatty acids

基于3-羟基脂肪酸的新型陆地古气候代理的开发

• 批准号: 2744743
• 金额: --
• 依托单位: University of Birmingham
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2019
• 资助国家: 英国
• 起止时间: 2019 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2744743
• 关键词: development; novel; terrestrial; palaeoclimate; proxies

A wide range of environmental information from both terrestrial and marine realms is required from palaeoclimate archives to better understand the climate system and to provide a palaeoclimatic context for predictions of future rates of climate change, impact and Earth system sensitivity. Overall, far less attention has been paid to terrestrial environments, compared to the marine realm, due to the paucity of ubiquitous biomarkers with quantitative palaeoclimatic utility. We have recently found strong correlations between 3-hydroxy fatty acid (3-OH-FA) distributions, synthesised within Gram-negative bacterial membranes, and environmental parameters (Wang et al., 2016). Based on this discovery we have defined new geochemical proxies for reconstructing temperature, pH and precipitation. The ubiquitous natural distribution of Gram-negative bacteria means that these new techniques for reconstructing past climate have huge potential.We have recently submitted the first manuscript to demonstrate that 3-OH-FA biomarkers can successfully reconstruct temperature and precipitation signals from an individual stalagmite (Wang et al, submitted). This PhD project will undertake the next exciting steps in the development of these biomarkers: - The production of new global scale calibrations to expand and refine the new proxies for pH and temperature and ensure wide uptake by the palaeoclimate community.- First applications of new proxies to a variety of palaeoclimate archives beyond speleothems (lake sediments, ocean drilling sediment cores) on a variety of time-scales (Holocene to Cenozoic). Methodology: Geological work: Compile a collection of soil and sediment samples which span gradients in temperature, hydrology and a diversity of bacterial and plant communities. Fresh samples will be obtained on field expeditions from regional transects (in the USA and Europe). In addition we have already obtained samples from the ISRIC soil repository and co-supervisor Griffiths possesses a frozen archive of soils from across the UK collected as part of nationwide soil surveys, and a recent NERC funded project (U-GRASS) under the Soil Security Programme.Experimental work: All samples will be subjected to organic geochemical extraction and clean-up and analytical methods: i.e. acid hydrolysis and digestion Wang et al., 2012), extraction with organic solvents, separation into chemical fractions and analysis by GC-FID, GC-MS.

古气候档案需要来自陆地和海洋领域的广泛环境信息，以更好地了解气候系统，并为预测未来气候变化率、影响和地球系统敏感性提供古气候背景。总体而言，与海洋领域相比，由于缺乏具有定量古气候效用的普遍存在的生物标志物，对陆地环境的关注要少得多。我们最近发现革兰氏阴性细菌膜内合成的 3-羟基脂肪酸 (3-OH-FA) 分布与环境参数之间存在很强的相关性 (Wang et al., 2016)。基于这一发现，我们定义了新的地球化学代理来重建温度、pH 值和降水量。革兰氏阴性细菌无处不在的自然分布意味着这些重建过去气候的新技术具有巨大的潜力。我们最近提交了第一份手稿，证明 3-OH-FA 生物标志物可以成功地重建单个石笋的温度和降水信号（王等人提交）。该博士项目将在这些生物标志物的开发中采取接下来令人兴奋的步骤： - 生产新的全球尺度校准，以扩展和完善 pH 和温度的新代理，并确保古气候界的广泛采用。 - 新代理的首次应用各种时间尺度（全新世到新生代）的古气候档案（湖泊沉积物、海洋钻探沉积岩芯）。方法：地质工作：收集土壤和沉积物样本，涵盖温度、水文梯度以及细菌和植物群落的多样性。新鲜样品将通过区域样带（美国和欧洲）的实地考察获得。此外，我们已经从 ISRIC 土壤储存库获取了样本，联合主管 Griffiths 拥有作为全国土壤调查的一部分收集的英国各地土壤的冷冻档案，以及最近由 NERC 资助的土壤安全项目 (U-GRASS)方案.实验工作：所有样品均进行有机地球化学萃取净化和分析方法：即酸水解和消解Wang et al., 2012)，用有机溶剂萃取，分离成化学组分并通过 GC-FID、GC-MS 进行分析。