Fractional solubility of aerosol iron: Synthesis of a global-scale data set
Fractional solubility of aerosol iron: Synthesis of a global-scale data set
复制标题
DOI：
10.1016/j.gca.2012.04.022
复制
发表时间：
2012-07
影响因子：
5
通讯作者：
E. Sholkovitz;P. Sedwick;T. Church;A. Baker;Claire F. Powell
中科院分区：
文献类型：
--
作者：
E. Sholkovitz;P. Sedwick;T. Church;A. Baker;Claire F. Powell
气溶胶沉积为公海提供了必需微量营养素铁的主要输入。生物有效性的一个关键参数是进入海洋溶解铁池的气溶胶铁的比例，即所谓的气溶胶铁溶解度分数 (%FeS)。在这里，我们展示了在公海、沿海海洋和一些大陆地点收集的~1100个样本的全球范围总气溶胶铁含量（FeT）和估计％FeS值的汇编，其中包括来自大西洋的新数据集。尽管用于定义“可溶性”气溶胶铁的方法多种多样，但我们的全球规模汇编显示，气溶胶铁的溶解度分数与总气溶胶铁负荷的函数关系具有非常一致的趋势，其中大量数据定义了双曲线趋势。我们观察到的全球和区域尺度数据的双曲线趋势可以通过简单的双组分混合模型充分描述，其中铁在散装气溶胶中的溶解度分数反映了“成石”矿物粉尘（高 FeT 和低 % FeS）和非成石“燃烧”气溶胶（低 FeT 和高 % FeS）的保守混合。越来越多的经验和基于模型的证据表明，人为燃料燃烧是这些非成石“燃烧”气溶胶的主要来源，这意味着人类排放是海洋气溶胶中铁溶解度的主要决定因素。 %FeSand 和 FeT 之间强大的全球范围关系为估计区域到全球范围内的气溶胶铁溶解度提供了一种简单的启发式方法。
Aerosol deposition provides a major input of the essential micronutrient iron to the open ocean. A critical parameter with respect to biological availability is the proportion of aerosol iron that enters the oceanic dissolved iron pool – the so-called fractional solubility of aerosol iron (%FeS). Here we present a global-scale compilation of total aerosol iron loading (FeT) and estimated %FeSvalues for ∼1100 samples collected over the open ocean, the coastal ocean, and some continental sites, including a new data set from the Atlantic Ocean. Despite the wide variety of methods that have been used to define ‘soluble’ aerosol iron, our global-scale compilation reveals a remarkably consistent trend in the fractional solubility of aerosol iron as a function of total aerosol iron loading, with the great bulk of the data defining an hyperbolic trend. The hyperbolic trends that we observe for both global- and regional-scale data are adequately described by a simple two-component mixing model, whereby the fractional solubility of iron in the bulk aerosol reflects the conservative mixing of ‘lithogenic’ mineral dust (high FeTand low %FeS) and non-lithogenic ‘combustion’ aerosols (low FeTand high %FeS). An increasing body of empirical and model-based evidence points to anthropogenic fuel combustion as the major source of these non-lithogenic ‘combustion’ aerosols, implying that human emissions are a major determinant of the fractional solubility of iron in marine aerosols. The robust global-scale relationship between %FeSand FeTprovides a simple heuristic method for estimating aerosol iron solubility at the regional to global scale.