Geotraces Pacific Section: Gallium, vanadium, and associated elements indicative of dust input and redox cycling

在2013年GEOTRACES东太平洋带状部分巡航期间，南密西西比大学的一名科学家将确定镓（Ga）和钒（V）的分布，以及V的氧化还原形态。 计划中的巡航轨迹是这项工作的理想之选，因为它将穿越影响这些元素的地球化学的各种海洋环境，即秘鲁边缘/上升流区和相关的氧气最低值区、从秘鲁边缘到塔希提岛的大气输入梯度和生物生产力，以及东太平洋海隆沿着的热液喷口。 本项目的具体目标包括：（1）研究表层海水Ga和Al分布的差异，估算沙尘输入;（2）确认在北太平洋观测到的表层海水Ga/Al比值与叶绿素分布之间的关系;（3）比较表层海水Mn的分布与Ga、Al的分布，区分陆架输入和气溶胶输入;（4）确定是否存在导致表层海洋V贫化的陆架V去除的证据;（5）检验东太平洋海隆下游的热液对V分布的影响;（6）比较了钒与硒、砷、和碘作为一种手段，检查水柱减少与平流相互作用减少沿海沉积物的重要性。因此，被选为本研究重点的元素将提供有关粉尘输入和氧化还原循环的信息，特别是与其他巡航参与者确定的其他元素相比时。 更广泛的影响：研究结果将纳入海洋学和海洋化学课程的教材。 作为该项目的一部分，将支助和培训一名研究生。 还注意到对高中生的指导。

During the 2013 GEOTRACES Eastern Pacific Zonal Section cruise, a scientist from the University of Southern Mississippi will determine the distributions of gallium (Ga) and vanadium (V), as well as V redox speciation. The planned cruise track is ideal for this effort because it will traverse various oceanic environments that influence the biogeochemistry of these elements namely, the Peru margin/upwelling zone and the associated oxygen minimum zone, gradients in atmospheric inputs and biological productivity from the Peru margin to Tahiti, and hydrothermal vents along the East Pacific Rise. Specific goals of the project include: (1) examine the discrepancy between surface water Ga and aluminum (Al) distributions and estimate dust inputs; (2) confirm the relationship observed in the North Pacific between the surface ocean Ga/Al ratio and the chlorophyll distribution; (3) compare the surface ocean manganese distribution with that of Ga, Al, and lead to differentiate between shelf and aerosol inputs; (4) determine if there is evidence of shelf V removal which contributes to the surface ocean V depletion; (5) test for hydrothermal influences on the V distribution downstream from the East Pacific Rise; and (6) compare V redox speciation with that of other elements including selenium, arsenic, and iodine as a means of examining the importance of water column reduction versus advective interactions with reducing coastal sediments. As such, the elements selected as the focus of this study, will provide information on dust input and redox cycling, especially when compared with other elements being determined by other cruise participants. Broader Impacts: Results from the study would be included into course materials for Oceanography and Marine Chemistry classes. One graduate student would be supported and trained as part of this project. Mentoring of high school student is also noted.