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

摘要：根据该奖项，该项目将研究风力驱动的沿海上升流对海洋边缘的重要性，以及它如何影响初级和次级生产。生产控制/影响来自于光带的碳输出通量、大气与海洋表层之间的二氧化碳交换以及海洋内部和海底沉积物中的碳固存。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建议的主要科学推动力。本提案旨在分析已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种代用物对全新世热极大期结束以来卡里亚科盆地水柱的气候和生态变化进行高分辨率调查。在Cariaco盆地，风力驱动的沿海上升流与热带辐合带（ITCZ）的季节位置密切相关，这是由太阳日照控制的一级。为了验证与上升流变率相关的强迫机制和生态响应的几种假设，将对代表连续6000年缺氧沉积的沉积物进行各种生物地球化学变量分析，这些变量作为已证实的古气候/古海洋代用物。计划的分析包括开发烯烃不饱和（UK.37指数）的高分辨率记录，测定有机碳、生物蛋白石、方解石以及藻类特异性生物标志物（如甾醇和烯烃）和陆源生物标志物（如木质素酚）的质量积累率。研究计划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，旨在破译这些物质合成的环境条件。该计划将资助一名博士生，一名年轻的研究技术人员和两名本科生。作为该研究项目教育部分的一部分，全新世气候代用物的数据集将被汇编在一个网站上，该网站与PI教授的一门名为“地球系统穿越时间”的课程有关。利用现有的加勒比合作组织项目，研究结果将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.