Department of Earth and Atmospheric Sciences, Cornell University, Ithaca, New York 14853, USA.
Ann Rev Mar Sci. 2009;1:245-78. doi: 10.1146/annurev.marine.010908.163727.
Atmospheric inputs of iron to the open ocean are hypothesized to modulate ocean biogeochemistry. This review presents an integration of available observations of atmospheric iron and iron deposition, and also covers bioavailable iron distributions. Methods for estimating temporal variability in ocean deposition over the recent past are reviewed. Desert dust iron is estimated to represent 95% of the global atmospheric iron cycle, and combustion sources of iron are responsible for the remaining 5%. Humans may be significantly perturbing desert dust (up to 50%). The sources of bioavailable iron are less well understood than those of iron, partly because we do not know what speciation of the iron is bioavailable. Bioavailable iron can derive from atmospheric processing of relatively insoluble desert dust iron or from direct emissions of soluble iron from combustion sources. These results imply that humans could be substantially impacting iron and bioavailable iron deposition to ocean regions, but there are large uncertainties in our understanding.
大气向开阔海域输入的铁被认为可以调节海洋生物地球化学。本综述综合了现有大气铁和铁沉积的观测结果，还涵盖了可利用铁的分布。本文还回顾了估算过去一段时间海洋沉积中时间变化的方法。据估计，沙漠尘埃铁占全球大气铁循环的 95%，而燃烧源的铁则占剩余的 5%。人类可能会显著改变沙漠尘埃（高达 50%）。与铁的来源相比，可利用铁的来源了解得较少，部分原因是我们不知道哪种铁的形态是可利用的。可利用铁可能来自相对不溶性的沙漠尘埃在大气中的处理，也可能来自燃烧源中可溶性铁的直接排放。这些结果表明，人类可能会对海洋区域的铁和可利用铁沉积产生重大影响，但我们的理解还存在很大的不确定性。
