Climate change in the Holocene: A multi-proxy case study

人们普遍认为海洋和极地海冰在全球气候变化中起着至关重要的作用。因此，海表温度和极地海冰重建对于确定地质过去的气候演化具有至关重要的意义。虽然过去200年的海冰直接记录被认为是相当准确的（利用过去30年的卫星成像），但只有通过使用“代理”措施（海冰的化学、物理或生物指标）才能获得更广泛的记录。目前项目的主要目的是测量从北冰岛大陆架获得的北极沉积物核心中一种不寻常的海冰化学标志物的浓度。由于这种化学物质，即所谓的高度支化的类异戊二烯（HBI），已经被我们证明是特定于海冰起源的，并且在极地沉积物中是稳定的，它在沉积物中的存在可以直接归因于以前的海冰覆盖。同样，海表温度（SST）的重建也可以通过分析沉积物中的长链不饱和酮来实现。在这个合作项目中，我们将对北冰岛大陆架的海洋核心进行多代理分析，该分析具有前所未有的时间分辨率。海温数据将由项目合作伙伴完成。这项调查的结果将根据已经从该岩心的其他代理获得的数据进行评估。鉴于现有数据的多样性，加上高时间分辨率，该项目代表了一个独特的“案例研究”机会，可以建立不同代理之间的关系，并使将来的古气候重建研究得到更充分的理解。这个项目的数据也将被气候变化建模者直接使用。该项目与理事会计划的其他方面配合得很好，显然与“极北”分类和“全球变化”ENRI都有100%的相关性。该项目性价比极高，特别是考虑到项目合作伙伴的承诺。所有必要的化学和分析要求都在普利茅斯大学的石油和环境地球化学小组内部进行。该项目还将受益于当地和国际上现有的额外工作人员专业知识。

It is widely acknowledged that the oceans and polar sea-ice play critical roles in global climate change. As such, sea surface temperature and polar sea-ice reconstruction should be of paramount importance in establishing climatic evolution of the geological past. Although direct records of sea-ice are considered to be reasonably accurate over the last 200 years (with satellite imaging for the past 30 years), it is only through the use of 'proxy' measures (chemical, physical or biological indicators of sea-ice) that a more extended record is achievable. The main aim of the current project is to measure the concentrations of an unusual chemical marker of sea ice in an Arctic sediment core obtained from the North Icelandic Shelf. Since this chemical, a so-called highly branched isoprenoid (HBI), has already been shown by us to be specific to a sea ice origin and is stable in polar sediments, its presence in sediments can be directly attributable to previous sea ice cover. Similarly, sea surface temperature (SST) reconstruction can be achieved by analysis of long chain unsaturated ketones in sediments. In this collaborative project, we will carry out a multi-proxy analysis of a marine core from the North Icelandic Shelf which has unprecendented temporal resolution. The SST data will be completed by the project partners. The results of this investigation will be evaluated against data already obtained from other proxies for this core. Given the diversity of the data available, together with the high temporal resolution, this project represents a unique 'case study' opportunity to establish the relationships between different proxies and to enable future studies in palaeoclimate reconstruction to be more fully understood. The data from this project will also be used directly by modellers of climate change.This project fits well with other aspects of the Council's programme and clearly has a 100% relevance to both the 'Polar North' classification and the 'Global Change' ENRI. The project represents excellent value for money, especially considering the commitment of the project partners. All of the necessary chemical and analytical requirements are held in-house within the Petroleum and Environmental Geochemistry Group at the University of Plymouth. The project will also benefit from additional staff expertise available both locally and internationally.