Collaborative Research: Investigation of Holocene Seasonality and Inter-annual Variability Along the California Current System

根据该合同，pi将对东北太平洋边缘全新世海洋学变化进行综合数据建模研究，以了解全新世气候和海洋学变化对东北太平洋边缘海洋和陆地群落（包括人类种群）的影响。古环境数据将来自加利福尼亚中部和不列颠哥伦比亚省考古遗址的氧同位素、微量元素和对软体动物贝壳的14C分析。作为美国国家科学基金会地质古生物学资助项目的一部分，这些贝壳中的大多数已经通过14C分析确定了各自的年代。通过耦合这三种生物地球化学示踪剂，并检查大量样本（整合了几年的生长）和骨骼内生长序列（提供周至月的时间分辨率），pi可以重建海洋温度、上升流强度和沿海地区淡水通量的千年、年际和季节变化。通过对现存软体动物的研究，pi将开发物种特有的同位素和小元素校准，并评估近岸物种固有的变异水平。为了将数据置于更广泛的背景下，pi将使用全球和区域尺度的大气-海洋耦合模式来研究气候强迫变化对各种时间尺度上的洋流、表面温度、上升流和降水的影响。将模型结果与代理数据进行比较将允许模型性能，并可能揭示代理记录中的关键差距。除了深入了解推动东北太平洋边缘气候和海洋学变化的因素外，pi还将使用我们的气候数据来测试全新世人类学和古生态转变的假设。

Under this award the PIs will perform an integrated data-modeling study of Holocene oceanographic changes along the NE Pacific margin to understand the impact of Holocene climatic and oceanographic changes on marine and terrestrial communities (including human populations) along the NE Pacific Margin. The paleoenvironmental data will come from oxygen isotope, minor element, and 14C analyses of dated mollusk shells from archaeological sites in central California and British Columbia. Most of these shells have already been individually dated via 14C analysis as part of a project supported by NSF Geology & Paleontology. By coupling these three biogeochemical tracers, and examining both bulk samples (which integrate several years of growth) and intraskeletal growth series (which provide weekly-to-monthly temporal resolution), the PIs can reconstruct millennial, inter-annual, and seasonal variability in ocean temperature, upwelling intensity, and freshwater flux to the coastal zone. Through studies of extant mollusks, the PIs will develop species-specific isotope and minor element calibrations and assess the levels of variance inherent to nearshore species. To place the data in broader context, the PIs will use globaland regional-scale coupled atmosphere-ocean models to study the impact of changes in climate forcing on ocean currents, surface temperature, upwelling, and precipitation on a variety of time scales. Comparison of model results with proxy data will permit model performance, and may reveal key gaps in the proxy record. In addition to gaining insight into the factors driving climatic and oceanographic change along the NE Pacific margin, the PIs will use our climate data to test hypotheses for Holocene anthropological and paleoecological transitions.