The impact of changing surface ocean conditions on the dissolution of aerosol iron
The impact of changing surface ocean conditions on the dissolution of aerosol iron
复制标题
DOI：
10.1002/2014gb004921
复制
发表时间：
2014-11-01
影响因子：
5.2
通讯作者：
Ussher, Simon J.
中科院分区：
文献类型：
--
作者：
Fishwick, Matthew P.;Sedwick, Peter N.;Ussher, Simon J.
溶解在海水中的气溶胶铁（Fe）的比例变化很大，并取决于气溶胶的组成和海水的物理化学条件，这可能会根据位置或全球环境变化而改变。在马尾藻海采集气溶胶和表层海水样品，并用于调查这些变化的条件对气溶胶Fe溶解在海水中的影响。我们的数据表明，海水温度，pH值和氧气浓度，在当前和预计的未来值的范围内，对气溶胶Fe的溶解没有显着的影响。然而，气溶胶的来源和组成对气溶胶Fe溶解度的影响最显着，具有最高的分数溶解度（高达3.2%）的最有害影响的样品。因此，海洋变暖和酸化对气溶胶铁溶解的影响不太可能像土地利用和化石燃料燃烧的变化那样重要。我们的实验结果还揭示了重要的变化，可溶性气溶胶Fe在溶液中的尺寸分布，这取决于海水的化学条件。在典型的条件下，大部分（77-100%）的铁从气溶胶释放到周围的海水中存在的胶体（0.02-0.4 μ m）的大小部分。然而，在存在足够浓度的强Fe结合有机配体（10 nM）的情况下，大部分气溶胶衍生的胶体Fe转化为可溶性Fe（
The proportion of aerosol iron (Fe) that dissolves in seawater varies greatly and is dependent on aerosol composition and the physicochemical conditions of seawater, which may change depending on location or be altered by global environmental change. Aerosol and surface seawater samples were collected in the Sargasso Sea and used to investigate the impact of these changing conditions on aerosol Fe dissolution in seawater. Our data show that seawater temperature, pH, and oxygen concentration, within the range of current and projected future values, had no significant effect on the dissolution of aerosol Fe. However, the source and composition of aerosols had the most significant effect on the aerosol Fe solubility, with the most anthropogenically influenced samples having the highest fractional solubility (up to 3.2%). The impact of ocean warming and acidification on aerosol Fe dissolution is therefore unlikely to be as important as changes in land usage and fossil fuel combustion. Our experimental results also reveal important changes in the size distribution of soluble aerosol Fe in solution, depending on the chemical conditions of seawater. Under typical conditions, the majority (77-100%) of Fe released from aerosols into ambient seawater existed in the colloidal (0.02-0.4 mu m) size fraction. However, in the presence of a sufficient concentration of strong Fe-binding organic ligands (10nM) most of the aerosol-derived colloidal Fe was converted to soluble Fe (