Paleo-Ocean Chemistry Based on Trace Element Records in Marine Sedimentary Opal: Implications for Aeolian Fluxes and the Effect of Fe on Biological Productivity

尽管现代海洋中存在铁限制的明确证据，但“古生产力”的沉积记录并没有提供尘埃通量变化与区域/全球生产力之间的联系。 斯克里普斯海洋研究所的一位科学家将通过分析生物蛋白石来研究微量元素化学与古生产力之间的关系。 从试点研究的结果，其中一个新开发的技术被用来分离和纯化沉积蛋白石碎屑污染物表明，这种矿物相忠实地记录溶解海洋浓度的宇宙射线产生的放射性核素（10 Be，26铝）和微量元素（铁，锰，钛，锌）。 因此，沉积柱内的一个沉积相可以用来直接比较的代理风输入的微量营养素（铁，钛）与生产代理（26铝/铝比）。 作为该项目的一部分，PI将继续扩大试点研究，使用南大洋深海软泥带的沉积物岩心，对该区域的古生产力进行综合评估。 此外，还将在赤道太平洋和东南大西洋的沉积物中确定微量元素和宇宙核素的时间记录，这两个地区的上升流和生产力截然不同。 预计这些区域对全球气候波动和微量营养素输入的反应各不相同，从而可与从南大洋获得的记录进行比较/对照。 预计这项研究将揭示过去海洋环境中的化学和生物生产力如何随着气候变化而变化。 就更广泛的影响而言，这项研究将记录生物蛋白石作为溶解微量元素浓度和宇宙射线产生的放射性核素的记录器的使用，并为海洋科学界提供一种新技术，用于将生物蛋白石与沉积物样品中的其他碎屑分离。 这项研究的结果将包括在一个新的气候展览中，该展览致力于科学家如何利用海洋沉积记录来推断过去的气候，题为《自然的时间胶囊》，于2006年秋季在伯奇水族馆的斯克里普斯探险家画廊开幕。 对研究生和本科生的培训和支持也包括在研究中。

ABSTRACTOCE-0454870Despite clear evidence for iron limitation in the modern ocean, the sedimentary record of "paleoproductivity" has not provided a link between changes in dust flux and regional/global productivity. A scientist from Scripps Institute of Oceanography will examine the relationship between trace element chemistry and paleoproductivity through analysis of biogenic opal. Results from a pilot study wherein a newly developed technique was used to separate and purify sedimentary opal from detrital contaminants indicated that this mineral phase faithfully records dissolved oceanic concentrations of cosmic ray-produced radionuclides (10Be, 26Al) and trace elements (Fe, Mn, Ti, Zn). Thus, one sedimentary phase within the sediment column could be used to compare directly a proxy for aeolian input of micronutrients (Fe, Ti) with a proxy for production (26Al/Al ratios). As part of this project, the PI will continue to extend the pilot study using sediment cores from the Southern Ocean diatomaceaous ooze belt to provide an integrated assessment of paleoproductivity in this region. In addition, the temporal records of trace elements and cosmic nuclides will be determined in sediments from the equatorial Pacific and the southeastern Atlantic, two contrasting regions of upwelling and productivity. These areas are expected to differ in their response to global climate fluctuations and micronutrient input, thereby providing a comparison/contrast with records obtained from the Southern Ocean. It is anticipated that this study will reveal how the chemistry and biological productivity in the marine environment has changed with climate in the past. In terms of the broader impacts, this study will document to use of biogenic opal as a recorder of dissolved trace element concentrations and cosmic ray-produced radionuclides, as well as provide the ocean science community with a new techniques for separating biogenic opal from other detritus within a sediment sample. Results from this study will be included in a new climate exhibit dedicated to how scientists use the marine sedimentary record to infer about past climate entitled Nature's Time Capsule opening in the Fall of 2006 at the Scripps Explorers Galley in the Birch Aquarium. Training and support of graduate and undergraduate students has been included in the study.