IODP Expedition Objective Research: Neogene productivity and biogenic sedimentation in the equatorial Pacific

该项目探讨的重要专题涉及赤道太平洋的海洋生产力、大气古CO2和过去26 Ma期间的全球碳循环，这些都是根据对国际海洋发展项目PEAT考察第320航次收集的沉积物岩心进行的古生物学和地球化学分析推断的。这次探险非常成功地从赤道取回了第一个完整的新生代记录。虽然是一个高生产力的区域，但EP的高营养负荷使其成为一个效率低下的生态系统，从而使其容易受到循环速率的快速变化的影响，并在海洋生物地球化学循环中发挥重要作用。在整个新生代的EP生物沉积的主要变化被认为是反映过去的变化，在这种循环和生产力。沉积硅藻组合将从腿320的核心作为生产力的指标进行分析，生物钡和生物硅将被用作出口生产的指标，和有机碳和碳酸钙的测量将了解过去的碳循环的变化。这种全面的多代理方法和微体古生物学分析将增加我们对中晚中新世期间赤道地区古生产力、碳输出和埋藏以及地球化学循环的理解。更广泛的影响：大气CO2水平受海洋生产力的强烈调控。通过分析沉积记录，了解过去地球温暖条件下海洋生产力的变化，可以深入了解古大气CO2水平的自然变化及其地球化学影响。这项研究将为更好地了解全球气候提供基础信息。该项目为本科生提供财政援助，并将支持和培训一名研究生。该项目很好地利用了以前对海洋综合发展方案考察的大量投资，并加强了海洋综合发展方案界内的国际合作。

This project addresses important topics concerning ocean productivity in the equatorial Pacific (EP), atmospheric paleo-CO2 and the global carbon cycle over the past 26 Ma period as inferred from paleontological and geochemical analyses of sediment cores collected from the IODP PEAT expedition, leg 320. This expedition was highly successful at retrieving the first complete Cenozoic record from the equator. Although a highly productive region, the high nutrient load of the EP makes it an inefficient ecosystem, thus making it susceptible to rapid changes in cycling rates and serving an important role in ocean biogeochemical cycles. Major changes in biogenic sedimentation in the EP throughout the Cenozoic is believed to reflect past changes in this cycling and in productivity. Sedimentary diatom assemblages will be analyzed from cores of leg 320 as indicators of productivity, bio-Ba and bio-Si will be used as indicators of export production, and organic carbon and CaCO3 measurements will be made to understand the past changes in carbon cycling. This comprehensive multi-proxy approach and micropaleontological analyses will increase our understanding of paleoproductivity, carbon export and burial, and biogeochemical cycling in the equatorial regions during the middle to late Miocene.Broader impacts: Atmospheric CO2 levels are strongly regulated by ocean productivity. Understanding past changes in ocean productivity during warm earth conditions from analysis of the sedimentary record provides insights into natural variations of paleo-atmospheric CO2 levels and the biogeochemical influences of this. This study will provide fundamental information for better understanding global climate. The project provides financial assistance for undergraduate students and will support and train a graduate student. The project takes good advantage of a large investment previously made in an IODP expedition and strengthens international collaborations within the IODP community.