Atmospheric Trace Element Inputs to Surface Ocean Waters I: Lead Isotope Tracers in the Atlantic

9522004教堂铅同位素将用作示踪剂，以量化百慕大近海马尾藻海表层水域的大气输入和生物地球化学过程，并将在南大西洋收集数据，作为同一时期拟议的第三次海委会微量元素巡航的一部分。这是特拉华大学首席调查人员和其他机构之间的协调努力。其中包括目前在NSF-ATM的支持下作为AEROCE计划第三阶段的一部分积极参与百慕大大气研究的人员，以及在NSF-OCE的支持下调查百慕大附近水域主要营养循环、生产力和相关碳基通量(JGOFS-BATS及相关活动)的其他科学家。现有的已存档的降水和海洋通量颗粒样本如果满足清洁收集标准，将首先被利用。拟议的研究将侧重于元素铅及其同位素示踪剂，包括稳定的铅(204,206,207,208)，以及放射性核素210Pb及其相关的母体/子体对，它们是226Ra，222Rn，210Bi和210Po系列的一部分。铅及其同位素将在百慕大AEROCE基地和百慕大附近的几艘邮轮上单独和综合采集大气样本进行测量。放射性铅(~(210)Pb)及其与子体~(210)Bi和~(210)Po的不平衡将揭示大气和表层海洋的清除作用。这些同位素的半衰期(分别为5天和138天)应与水中清除颗粒活性元素(如铋)和生物活性元素(如Po)的过程相称。通过对地表混合层至温跃层中溶解的210Po剖面的模拟，将确定地表水中的涡旋扩散系数，并随后用于限制新的生产率。通常，铅同位素模拟将约束S对地表水的垂直和水平贡献，并标定铅的混合和颗粒清除。

9522004 Church Pb isotopes will be used as tracers to quantify the atmospheric inputs to and biogeochemical processes in the surface waters of the Sargasso Sea off Bermuda, and data will be gathered in the South Atlantic as part of a proposed third IOC trace element cruise during the same period. This is a coordinated effort between the University of Delaware Principal Investigators and other institutions. Included are those currently active in studies of the Bermuda atmosphere as part of the AEROCE program in its third phase with support from NSF-ATM, and other scientists investigating the major nutrient cycles, productivity, and associated carbon based flux (JGOFS-BATS and associated activities) in the waters off Bermuda under NSF-OCE support. Existing archived samples of precipitation and oceanic flux particles will be utilized first if they satisfy clean collection criteria. The proposed study will focus on the element Pb and its isotope tracers which include stable Pb (204,206,207,208), and the radioactive nuclide 210Pb with the associated parent/daughter pairs which are part of the series 226 Ra, 222Rn, 210Bi, and 210Po. Lead and its isotopes will be measured in individual and integrated atmospheric samples to be taken at the AEROCE Bermuda site, and on board several cruises off Bermuda. The radioactive lead (210Pb) and its disequilibrium with the daughters 210Bi and 210Po will reveal of atmospheric and surface ocean scavenging. The half lives of these isotopes (5 and 138 days respectively) should be commensurate with processes such as aqueous scavenging of particle reactive elements (such as Bi), and bio-active elements (such as Po). Through modeling of dissolved 210 Po profiles in the surface mixed layer down to the thermocline, eddy diffusion co-efficients in the surface waters will be determined and subsequently used to place constraints on new production rates. Generally, lead isotope modeling will constrain vertical and horizontal contribution s to the surface waters, and calibrate the mixing and particle scavenging of Pb.