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.

需要从古气候档案中获得来自陆地和海洋领域的广泛环境信息，以便更好地了解气候系统，并为预测未来气候变化速率、影响和地球系统敏感性提供古气候背景。总体而言，由于缺乏普遍存在的具有定量古气候效用的生物标志物，与海洋领域相比，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指标来重建温度、pH和降水。革兰氏阴性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篇论文，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（Wang等，提交）。该博士项目将在这些生物标记物的开发中开展下一个令人兴奋的步骤：-生产新的全球尺度校准，以扩展和完善pH和温度的新代用物，并确保古气候群落广泛采用。-首次将新的代用指标应用于不同时间尺度（全新世到新生代）的各种古气候档案，而不仅仅是洞穴主题（湖泊沉积物、海洋钻探沉积物岩心）。方法：地质工作：收集土壤和沉积物样本，这些样本跨越温度、水文和细菌和植物群落的多样性梯度。新的样本将在实地考察中从区域样带（在美国和欧洲）获得。此外，我们已经从ISRIC土壤库获得了样本，联合主管Griffiths拥有来自英国各地的土壤冷冻档案，作为全国土壤调查的一部分，以及最近NERC资助的土壤安全计划下的项目（U-GRASS）。实验工作：所有样品将进行有机地球化学提取和清理和分析方法：酸水解和消化（Wang et al., 2012），有机溶剂提取，分离成化学组分，GC-FID， GC-MS分析。