Nanoparticles, Colloids and their relationship to Titanium, Aluminium and Iron solubility in the Open Ocean

本文拟对大气尘埃的主要组成成分Al、Fe和Ti三种主要地壳元素的海洋生物地球化学进行详细研究。这三种元素在海水中均发生强烈水解，导致其溶解度低，颗粒反应性高，在公海海水中浓度低（Al: 0.3 - 90 nM, Fe: 50 - 2000 pM, Ti: 3- 300 pM）。虽然目前对铁的生物地球化学有很强的关注，但对铝的研究很少，对钛的研究就更少了。PI最近开发了两种新的钛和铝的伏安形态形成技术，首次可以检查钛和铝在公海海水中的原位形态和反应动力学。拟议的工作是基于在大西洋和南大洋的一系列巡航，在那里将测量这些金属的可溶性（x < 10 kDa），胶体（10 kDa < x < 0.2 um）和颗粒（x >0.2 um）浓度。实验室研究将集中于这些元素在海水中的溶解度；这对钛尤其重要，因为没有关于海水的可靠数据，对所有三种金属来说，要了解这些金属在深海中的运输以及通过上涌和扩散向地表水的供应。

We propose here to investigate in detail the marine biogeochemistry of three major crustal elements, Al, Fe and Ti which are major constituents of atmospheric dust deposited to the ocean. All 3 elements are strongly hydrolysed in seawater resulting in low solubilities and high particle reactivity resulting in low concentrations in open ocean seawater (Al: 0.3 - 90 nM, Fe: 50 - 2000 pM, Ti: 3- 300 pM). While presently there is a strong focus on the biogeochemistry of iron, there has been little work performed on Al and even less on Ti. The PI has recently developed two new voltammetric speciation techniques for Ti and Al that allow for the first time an examination of the in situ speciation and reaction kinetics of Ti and Al in open ocean seawater. The proposed work is based around a series of cruises in the Atlantic and Southern Ocean, where soluble (x < 10 kDa), colloidal (10 kDa < x < 0.2 um) and particulate (x >0.2 um) concentrations of these metals will be measured. Laboratory investigations will focus on the solubility of these elements in seawater; this is particularly important with regard to Ti, where no reliable data exist for seawater, and for all the 3 metals in understanding the transport of these metals in the Deep Ocean and supply to surface waters by upwelling and diffusion.