Biogeochemical Cycling Of Barium In The Arabian Sea

阿拉伯海中钡的生物地球化学循环

• 批准号: 9311500
• 负责人: Kelly Falkner
• 金额: $ 28.14万
• 依托单位: Oregon State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-07-01 至 1997-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9311500&HistoricalAwards=false
• 关键词: Biogeochemical; Cycling; Barium; Arabian; Sea

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.

9311500福克纳海洋中所有微量元素的最大和最精确的数据库是钡的数据库，其浓度在1970年的S计划中作为GEOSECS计划的一部分在全球范围内进行了测量。从这一努力中，人们证实了Ba在海洋中经历了类似营养的循环，它的行为更像是生物体硬部分的成分(即硅和碱度)，而不是其组织的成分(即P和N)。对颗粒物质的研究表明，负责巴迁移的主要相是矿物重晶石(BaSO4)，它以某种方式在腐烂的有机体提供的微环境中沉淀，并倾向于积累在生产力高的地带下面的沉积物中。这种对巴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，在有孔虫测试的方解石晶格中记录的古Ba分布。正在被重建，作为通过冰川/间冰期过渡对海洋环流变化的制约。已提议在选定地点每年对珊瑚进行分带，以监测与厄尔尼诺事件有关的上升流条件的变化。沉积Ba被认为是上覆地表水域古生产力的指标，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真光带碳净输出速率的衡量标准。虽然巴作为一种调查工具的发展取得了相当大的进展，但要实现其全部潜力，需要对其在现代海洋中的行为有更彻底的了解。这项研究将有助于对溶解的巴进行分析，以解决有关海洋中巴循环的悬而未决的问题。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海洋建模研究。