A High Resolution Record of Upwelling in the Tropical Atlantic: Atmospheric Forcings and Biogeochemical Consequences

摘要：根据这一奖项，国际海洋研究所将调查风力驱动的沿海上升流对海洋边缘的重要性，以及这如何影响初级和次生生产。生产控制/影响真光带的碳出口通量、大气和表层海洋之间的二氧化碳交换以及海洋内部和底层沉积物中的碳固存。了解全新世的气候变化如何影响风、上升流、海洋生产力和碳输出之间的相互作用，是这一提议的主要科学推动力。这项建议旨在分析已经收集和确定年代的沉积物的生物地球化学成分，并使用校准良好的多个替代物对自全新世最高温度结束以来Cariaco盆地水柱的气候和生态变化进行高分辨率调查。Cariaco盆地由风驱动的沿海上升流与热带辐合带(ITCZ)的季节位置密切相关，热带辐合区是受太阳辐射控制的一级。为了检验与上升流变化有关的强迫机制和生态反应的几个假说，将对代表连续6 000年缺氧沉积的沉积物进行分析，以确定作为已证实的古气候/古海洋学指标的各种生物地球化学变量。研究计划中还包括对藻类和陆源生物标志物的稳定碳同位素组成的分析，这些标志物旨在破译合成这些材料的环境条件。这项提案将资助一名博士生、一名年轻的研究技术人员和两名本科生。作为这一研究项目的教育部分的一部分，全新世气候指标的数据集将在一个网站上汇编，该网站与国际地球科学研究所教授的题为《地球系统穿越时间》的课程有关。结果将通过利用现有的Cariaco计划与委内瑞拉的同事和学生分享。

Abstract: Under this award the PI will investigate the importance of wind-driven coastal upwelling to the ocean margins and how this impacts primary and secondary production. Production controls/affects carbon export flux from the euphotic zone, CO2 exchange between the atmosphere and surface ocean and carbon sequestration in the ocean interior and underlying sediments. Understanding how climatic changes in the Holocene have affected the interaction among winds, upwelling and oceanic productivity and carbon export is the major scientific impetus for this proposal. This proposal seeks to analyze the biogeochemical compositions of already collected and dated sediments and use well-calibrated multiple proxies to undertake a high-resolution investigation of the climatic and ecological changes in the water column of the Cariaco Basin since the end of the Holocene Thermal Maximum. Wind-driven coastal upwelling in the Cariaco Basin is intimately tied to the seasonal position of the Intertropical Convergence Zone (ITCZ), which is to a first order controlled by solar insolation. In order to test several hypotheses regarding the forcing mechanisms and ecological responses associated with upwelling variability, sediments representing a continuous 6,000 years of anoxic deposition will be analyzed for a variety of biogeochemical variables that serve as proven paleoclimatic/paleoceanographic proxies. The planned analyses include development of a high resolution record of alkenone unsaturation (UK.37 index), determination mass accumulation rates for organic carbon, biogenic opal, calcite as well as for algal-specific biomarkers, such as sterols and alkenones, and terrigenous biomarkers, such as lignin phenols. Also included in the research plan are analyses of the stable carbon isotopic compositions of algal and terrigenous biomarkers designed to decipher the environmental conditions under which these materials were synthesized. This proposal will fund one Ph.D. student, a young research technician and two undergraduate students. As part of the educational component of this research project, data sets of Holocene climate proxies will be compiled in a website associated with a course taught by the PI entitled Earth Systems Through Time. Results will be shared with colleagues and students in Venezuela by taking advantage of the existing CARIACO program.