Ge/Si-Opal and the "Missing Sink"-Investigation of Germanium Geochemistry and Paleoredox

PI计划继续研究海洋中锗和二氧化硅的地球化学循环，以及沉积物岩心中Ge/ si -蛋白石记录的解释。本文的两个主要目标是：1)利用孔隙水和沉积物分析Ge来研究Ge的成岩行为；2)验证Ge和Si在生物吸收过程中不分异的假设。根据这项建议分析的样本代表了一组独特的海洋沉积物，孔隙水，沉积物陷阱材料，这些材料是由PI在最近的巡航中收集的。这一建议提供了关闭海洋中Ge平衡的机会，因为在亚氧带的成岩反应可能代表了平衡海洋中蛋白石、河流和热液Ge/Si循环所需的非蛋白石“缺失的Ge汇”。这些结果将有助于更好地解释海洋沉积物Ge/ si -蛋白石和蛋白石堆积记录，从而更深入地了解气候变化、海洋化学和古生产力之间的相互作用。

ABSTRACT FROELICH / 9811199 The PI proposes to continue his studies into the geochemical cycling of germanium and silica in the ocean, and the interpretation of Ge/Si-opal records in sediment cores. The two major goals of this proposal are to: 1) use pore water and sediment analyses of Ge to study the diagenetic behavior of Ge, and 2) test the hypothesis that Ge and Si are not fractionated during biouptake. The samples to be analyzed under this proposal represent a unique set of marine sediment, pore water, sediment trap materials, which have been collected by the PI on recent cruises. This proposal provides the opportunity to close the Ge balance in the oceans, since diagenetic reactions in the suboxic zone may represent a non-opal "missing Ge-sink" needed to balance the opal, fluvial and hydrothermal Ge/Si cycle in the ocean. These results will permit a better interpretation of the marine sediment Ge/Si-opal and opal accumulation records, and thus provide a deeper understanding of the interactions among climate change, ocean chemistry and paleoproductivity.