Speciation of Iron In A Multiphasic Atmosphere

在大气中，铁在水相和固相中的含量各不相同。铁已被证明是二氧化硫自氧化以及云和雾中酸度产生的重要催化剂。最近的实地研究提供了强有力的证据表明，来自大气沉积的铁是公海某些区域各种浮游植物的限制生长营养物质。因此，大气中各种形式的铁的沉积(即氧化还原状态和物种)可能是控制海洋浮游植物生产的关键因素，而海洋浮游植物的生产反过来又可能影响大气中的二氧化碳水平。公共政策研究所建议调查从代表城市、农村和偏远大气的不同地点收集的大气水滴和气溶胶样本中铁的详细化学形态。他们计划确定从海洋和大陆环境中收集的云、雾和雨水中铁的各种固相和水相化学形态和氧化态(形态)，并在热力学和动力学耦合模型的框架内解释实验观察结果。

Iron is found at variable levels in the atmosphere in both aqueous-phases and solid phases. Ferric iron has been shown to be an important catalyst for the autoxidation of SO2 and concomitant generation of acidity in clouds and fogs. Recent field research has provided strong evidence that Fe derived from atmospheric deposition is a limiting growth nutrient for various species of phytoplankton in some regions of the open ocean. Thus the atmospheric deposition of iron in various forms (i.e. redox states and species) could be a critical factor in controlling oceanic phytoplankton production which in turn may affect atmospheric CO2 levels. The PIs propose to investigate the detailed chemical speciation of iron in atmospheric water droplets and in aerosol samples collected from a variety of locations representative of urban, rural and remote atmospheres. They plan to determine the various solid-phase and aqueous-phase chemical forms and oxidation states (speciation) of iron present in cloud-, fog- and rainwater collected from marine and continental environments and to interpret the experimental observations within the framework of coupled thermodynamic and kinetic models.