Collaborative Research: Seasonal climate change over the last two millennia from archaeological sources in the subtropical eastern North Atlantic region

在过去两千年中，对人类和气候影响敏感的亚热带沿海地区的海表温度（SST）的季节变化是如何变化的？亚热带沿海地区工业化前气候的季节性记录很少，但对理解对人类和生态系统的影响至关重要。本研究的目的是重建近两千年来四个暖、冷气候区间的夏季和冬季海温。这将利用古气候代用物（间接测量海温）来实现，这些代用物保存在加那利群岛土著居民积累的考古沉积物的贝壳中。研究结果将促进对人类与气候相互作用的认识，例如气候变异对史前人类生存模式和生态敏感栖息地行为的长期影响。该项目将培养从高中到博士水平的学生，目标是来自低收入家庭的本科生、第一代大学生和代表性不足的少数民族成员，利用已建立的项目，包括麦克奈尔学者、科学与工程女性和向上发展项目。通过北卡罗来纳大学科学与教学学士学位教育计划，未来的高中地球科学教师将进行研究，为K-12科学课程提供实验课程。该项目促进了美国和西班牙科学家之间的国际和多学科合作。结果将以英语和西班牙语向专家和公众传播，这将吸引美国和其他地方的不同受众。利用氧同位素（delta18O）时间序列的放射性碳定年的加那利群岛考古髌骨（软体动物：腹足类）壳，研究了几个关键的百年增冷突变（罗马暖期、汪达尔极小期或黑暗时期冷期、中世纪气候异常和小冰期），并将其与20世纪后期进行了比较。主要目标是：(1)利用仪器记录作为可靠的季节海温库，校准和验证假丝酵菌活标本的氧同位素年代学（壳体生长模式）；(2)利用放射性碳定年的考古贝壳重建了近两千年来与我们快速变暖的世界相关的重要气候突变期的海温剖面。该研究结果将用于探讨北大西洋涛动（NAO）的时间变化，NAO是北大西洋大气变率的一个关键特征，主要发生在冬季。该地理位置提供了一个独特的机会来研究工业化前气候变暖和变冷时期的NAO阶段及其在亚热带锋面的变化。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

How has the seasonal range in sea surface temperature (SST) changed over the last two millennia along subtropical coasts that are inherently sensitive to human and climate impacts? Seasonally-resolved records of preindustrial climate in subtropical coastal settings are few but critical to understanding impacts on humans and ecosystems. The goal of this research is to reconstruct summer and winter SST during four warm vs. cold climate intervals from the last two millennia. This will be achieved using paleoclimate proxies (indirect measures of SST) preserved in shells from archaeological deposits accumulated by aboriginal people in the Canary Islands. Outcomes will advance knowledge of human-climate interactions, such as the long-term effects of climate variability on prehistoric human subsistence patterns and behavior in ecologically sensitive habitats. This project will train students from high school to PhD level, targeting undergraduate students from low-income households, first-generation college students, and members of under-represented ethnic groups, using established programs including McNair Scholars, Women in Science and Engineering, and Upward Bound Programs. Through the UNC Baccalaureate Education in Science & Teaching program, future high-school earth science teachers will perform research that will generate laboratory curricula for K-12 science courses. This project fosters international and multidisciplinary collaboration among scientists from the US and Spain. Results will be disseminated to both specialists and the general public in both English and Spanish, which will engage a diverse audience in the US and elsewhere. Using oxygen isotope (delta18O) time-series of radiocarbon-dated archaeological Patella candei (Mollusca: Gastropoda) shells from the Canary Islands, several critical abrupt multi-centennial warming and cooling transitions (Roman Warm Period, Vandal Minimum or Dark Ages Cool Period, Medieval Climate Anomaly, and Little Ice Age) will be examined and compared to the late 20th century. The main goals are to: (1) calibrate and validate oxygen isotope sclerochronology (shell growth patterns) of living specimens of P. candei with instrument records as credible repositories of seasonal SST; and (2) reconstruct SST profiles from radiocarbon-dated archaeological shells during important abrupt climate intervals over the last two millennia relevant to our rapidly warming world. Results from this investigation will be then used to explore temporal variations of the North Atlantic Oscillation (NAO), which is a key feature of atmospheric variability in the North Atlantic and mainly operates during the winter. The geographic location offers a unique opportunity to examine the NAO phase and its shifts in the subtropical fronts during preindustrial warming and cooling climate episodes.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.