Distribution and Geochemical Cycling of Cerium and Cobalt inthe Upper Water Column

本文研究了海洋上层水柱中痕量元素Co和Ce的氧化还原化学，以评价氧化还原过程在其地球化学中的作用。现有数据表明，这两种元素具有相似的上层水柱分布，并经历了类似于海水中锰的氧化还原转变。特别是，所有这三种元素经常表现出表面浓度极大值。对于锰来说，这部分归因于动态的光化学/微生物氧化还原循环，尽管氧化还原和非氧化还原过程的相对重要性尚不清楚。在野外环境水平上对氧化还原和吸附动力学的测量将被纳入这些元素的上层海洋清除模型，并与实际分布进行比较，以评估氧化还原反应的重要性。Ce的非氧化还原过程将通过同时跟随其非氧化还原反应性邻位稀土元素而受到限制。将对Ce和Co进行比较研究，以确定Co作为生物必需元素的作用(参见Ce)影响其上水柱的地球化学和分布。

This is a study of the oxidation and reduction chemistry of the trace elements Co and Ce in the upper marine water column to evaluate the role redox processes play in their geochemistries. Existing data suggest that both elements have similar upper water column distributions and undergo similar redox transformations analogous to Mn in seawater. Particularly, all three elements frequently exhibit surface concentration maxima. For Mn this has been partially attributed to a dynamic photochemical/microbial redox cycle, although the relative importance of redox and non-redox processes are not known. Measurements of redox and adsorption kinetics made at ambient levels in the field will be incorporated into an upper ocean scavenging model for these elements and compared with actual distributions to evaluate the importance of the redox reactions. Non-redox processes for Ce will be constrained by following its non-redox reactive neighbor lanthanides simultaneously. Ce and Co will be studied comparatively to determine how the role of Co as a biologically essential element (cf. Ce) influences its upper water column geochemistry and distribution.