"Warm Times, Cold Times:-Quantitative Reconstructions of Near-Shore Environments Over the Last 2000 Years in Vestfirdir, NW Iceland: Natural Changes and Human Responses

“温暖时期，寒冷时期：冰岛西北部韦斯特菲尔过去 2000 年近岸环境的定量重建：自然变化和人类反应

• 批准号: 0326776
• 负责人: John Andrews
• 金额: --
• 依托单位: University of Colorado at Boulder
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-08-15 至 2007-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0326776&HistoricalAwards=false
• 关键词: Warm; Times; Cold; Quantitative; Reconstructions

ABSTRACTAndrewsOPP-0327187A better understanding of future environmental change is a pressing need of human society today and projections can be tested and evaluated by reconstructing the ranges and rates of past changes. The goal of this project is to develop a quantitative reconstruction of the marine climate Vestfirdir, north Iceland over the last 2000 years. Northern Iceland was chosen because of its sensitive location. This small area encapsulates climatic changes throughout much of the North Atlantic because it lies at the boundary between the Atlantic and Polar/Arctic realms, which drive much of the change. In addition, this is ideal area for climate reconstruction because it has 1) an extensive database of modern instrumental climate data, 2) a 1,200 year historical documentary climate record, and 3) well dated, high-resolution sediment cores containing an archive of natural climate variability. The research will reconstruct seasonal and annual temperature variations based on the stable isotopic composition of marine molluscs from three marine cores in Vestfirdir. The isotope data will be calibrated against the modern instrumental record and applied to molluscs in the cores. Seasonal to annual temperature estimates will be achieved through analysis of 60 individuals, with life spans of two to ten years, that lived during modern times, through the Settlement of Iceland (AD 871) and beyond the interval of human impact to c. 2000 years ago. The use of the micromilled molluscs in marine cores is the only way, at present to obtain seasonally- to-annually resolved climate data from Iceland, beyond the instrumental and documentary record. The short, but annually resolved records are placed within an environmental framework through analysis of other traditional proxy records. Drawing on earlier analyses of these cores, major environmental changes of the past are identified. These include a prolonged "cold" interval between 70 and 400 yr B.P. (ca. AD 1930 back to 1600), an interval with lower ?18O (CaCO3) (warmer) values around AD 1000, and a cool interval centered at AD 670. The project will select molluscs for analysis within these .warm. and .cold. intervals. In order to study the human dimensions of these changes, emphasis will be placed on the period from the Settlement of Iceland (c. AD 871) to the present. Isotope-based temperature reconstructions will be used to evaluate historical records of Icelandic sea-ice incidence and fisheries catches, with the main goals of: 1) determining the role of oceanic variability in the productivity of Icelandic fisheries; and 2) isolating periods when non-climatic factors might have played a role in fisheries variations. The impact of the reconstructed marine climates on biodiversity will be measured by changes in benthic foraminiferal assemblages. Broader Impacts This project represents a multidisciplinary evaluation and analysis of the role of climate change on the nearshore marine climate and its association with changes in historical fisheries practices and catches. It represents an international effort, with researchers from the USA and Canada and with co-operation from several colleagues in Iceland. It also fosters collaboration between NSF and Rannis (the Icelandic Science Foundation). Links with the archeological community currently working on the zooarcheology of sites in northern Iceland will be strengthened. This collaboration will enable analysis of stable isotopes on fish otoliths found in the refuse from these sites and comparison of these variations with the stable isotope data from the marine cores. The project will educate both graduate and undergraduate students, and will be beneficial in the training of young scientists in geochemical methods and micro- and macro -paleontology.

更好地了解未来的环境变化是当今人类社会的迫切需要，预测可以通过重建过去变化的范围和速度来检验和评估。该项目的目标是对冰岛北部Vestfirdir地区过去2000年的海洋气候进行定量重建。选择冰岛北部是因为其敏感的地理位置。这个小区域概括了北大西洋大部分地区的气候变化，因为它位于大西洋和极地/北极地区之间的边界，而极地/北极地区推动了大部分变化。此外，这是一个理想的气候重建地区，因为它有1)广泛的现代仪器气候数据数据库，2)1200年的历史文献气候记录，以及3)年代准确、高分辨率的沉积物岩心，其中包含自然气候变率的档案。该研究将基于Vestfirdir三个海洋岩心中海洋软体动物的稳定同位素组成重建季节和年温度变化。同位素数据将根据现代仪器记录进行校准，并应用于岩心中的软体动物。通过对60个寿命在2到10年的个体的分析，可以获得季节性到年度的温度估计，这些个体生活在现代，经历了冰岛定居（公元871年），并超越了人类影响的间隔，直到大约2000年前。目前，除了仪器和文献记录之外，在海洋岩心中使用微磨软体动物是获得冰岛季节性至年度解决气候数据的唯一方法。通过分析其他传统的代理记录，将简短但每年解决的记录置于环境框架内。根据对这些岩心的早期分析，确定了过去的主要环境变化。其中包括公元前70年至400年（约公元1930年至1600年）的一个漫长的“寒冷”时期。18O (CaCO3)（较温暖的）值大约在公元1000年，而以公元670年为中心的较冷间隔。该项目将选择软体动物进行分析。和.cold。间隔。为了研究这些变化的人类层面，重点将放在从冰岛定居（公元871年）到现在的时期。基于同位素的温度重建将用于评估冰岛海冰发生率和渔业捕获量的历史记录，其主要目标是：1)确定海洋变率在冰岛渔业生产力中的作用；2)隔离非气候因素可能在渔业变化中起作用的时期。重建的海洋气候对生物多样性的影响将通过底栖有孔虫组合的变化来衡量。本项目对气候变化对近岸海洋气候的影响及其与历史渔业实践和渔获量变化的关系进行了多学科评估和分析。它代表了一项国际努力，来自美国和加拿大的研究人员以及冰岛的几位同事进行了合作。它还促进了国家科学基金会和冰岛科学基金会之间的合作。将加强与目前在冰岛北部遗址进行动物考古工作的考古团体的联系。这项合作将能够分析在这些地点的垃圾中发现的鱼耳石的稳定同位素，并将这些变化与海洋岩心的稳定同位素数据进行比较。该项目将培养研究生和本科生，并将有利于培养地球化学方法和微观和宏观古生物学方面的青年科学家。