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

尽管现代海洋中铁的限制有明确的证据，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成因蛋白石来研究微量元素化学和古生产力之间的关系。利用一种新开发的技术从碎屑污染物中分离和提纯沉积蛋白石的初步研究结果表明，该矿物相忠实地记录了宇宙射线产生的放射性核素(10Be、26Al)和微量元素(Fe、Mn、Ti、Zn)在海洋中的溶解浓度。因此，沉淀柱中的一个沉积相可以用来直接比较风成输入微量营养素(Fe、Ti)的替代物和生产的替代物(26Al/Al比)。作为该项目的一部分，国际地球物理研究所将继续利用南大洋硅藻软泥带沉积岩芯扩大试点研究，以提供对该区域古生产力的综合评估。此外，微量元素和宇宙核素的时间记录将在赤道太平洋和东南大西洋的沉积物中确定，这两个地区是上升流和生产力的对比区域。预计这些区域对全球气候波动和微量营养素投入的反应将有所不同，从而与从南大洋获得的记录进行比较/对比。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气候变化。在更广泛的影响方面，这项研究将记录使用生物蛋白石作为溶解的微量元素浓度和宇宙射线产生的放射性核素的记录器，并向海洋科学界提供一种将生物蛋白石从沉积物样本中的其他碎屑中分离出来的新技术。这项研究的结果将被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，该展览的标题是2006年秋季在桦树水族馆的斯克里普斯探险家厨房开放的自然时间胶囊。这项研究还包括对研究生和本科生的培训和支持。

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.