Biogeochemical Cycling Of Barium In The Arabian Sea

小行星9311500 海洋中任何微量元素的最大和最精确的数据库是钡的数据库，其浓度是在1970年代作为GEOSECS计划的一部分在全球范围内测量的。 通过这一努力，人们证实钡在海洋中进行类似营养物的循环，其行为更像生物体硬部的成分（即硅和碱度），而不是其组织的成分（即磷和氮）。对颗粒物的研究表明， 钡的运输是重晶石矿物（BaSO 4），它在腐烂的生物体提供的微环境中以某种方式沉淀下来，并倾向于在高生产率区域下面的沉积物中积累。 这种对钡循环的简单理解为它作为各种重要海洋过程的探测器的发展铺平了道路。例如，古钡分布，记录在方解石晶格的有孔虫测试。通过冰川/间冰期过渡，正在被重建为对海洋环流变化的约束。 在选定的地点每年带状珊瑚的钡钙比已被提议监测与厄尔尼诺事件有关的上升流条件的变化。 沉积Ba被认为是上覆地表沃茨中古生产力的一个指标，在更直接的时间尺度上，水柱中的悬浮颗粒重晶石被认为是衡量真光层碳输出净速率的一个指标。 虽然Ba作为一种调查工具的发展已经取得了相当大的进展，但要充分发挥其潜力，需要更深入地了解其在现代海洋中的行为。 这项研究将有助于溶解钡分析，以解决悬而未决的问题，钡循环在海洋中。 此外，生成的数据将用于与法国和比利时同事合作进行的印度洋和南极洋建模研究。

9311500 FALKNER The largest and most precise data base for any trace element in the oceans is that of barium whose concentrations were measured on the global scale as part of the GEOSECS program in the 1970's. From that effort, it was confirmed that Ba undergoes nutrient-like cycling in the oceans and that it behaves more like the constituents of the hard parts of organisms (i.e. Si and alkalinity) than those of their tissues (i.e. P and N). Work on particulate matter has shown that the principal phase responsible for the transport of Ba is the mineral barite (BaSO4), which is somehow precipitated in micro environments provided by decaying organisms and tends to accumulate in the sediments underlying zones of high productivity. This simple understanding of Ba cycling has paved the way for its development as a probe for a variety of important oceanic processes. For example, paleo-Ba distributions, as recorded in the calcite lattices of foraminifera tests. are being reconstructed as a constraint on changes in oceanic circulation through glacial/interglacial transitions. Barium to Ca ratios in annually banding corals at select locations have been proposed to monitor changes in upwelling conditions associated with El Nino events. Sedimentary Ba is thought to serve as an index of paleo-productivity in overlying surface waters and on a more immediate time-scale, suspended particulate barite in the water column has been suggested to provide a measure of the net rate of carbon export from the euphotic zone. While considerable strides in the development of Ba as an investigative tool have been made, realization of its full potential requires a more thorough understanding of its behavior in the modern ocean. This study will contribute dissolved Ba analyses to resolve outstanding issues regarding Ba cycling in the oceans. In addition, the data generated will be used in Indian and Antarctic Ocean modeling studies being conducted in collaboration with French and Belgian colleagues.