PHOsphorus Speciation in mineral Dust and Marine Aerosol Particles

浮游植物等维持海洋食物链和生物的海洋微生物的生长需要大量营养素，如磷。另一方面，浮游植物物种向大气中排放与气候相关的有机化合物，如二甲基硫，这些化合物可被氧化成硫酸，随后可能导致形成可充当云凝结核的新颗粒。因此，了解这些微生物对磷的利用率对于了解海洋-大气相互作用非常重要。大气沉积是磷流入公海的主要来源;然而，仍然需要关于大气磷浓度、通量、生物利用率和来源的资料，这对于了解磷在海洋中，特别是在热带北大西洋和东南大西洋区域的命运是必要的。现有的少数数据主要是短期巡航测量数据，其应用局限于了解季节周期和长期预测。为了提高我们对控制这些海洋区域磷的可利用性和生物可利用性的来源和因素的认识，应长期测量大气中粒度分辨和散装气溶胶颗粒中的磷。此外，分析方法将开发和优化（基于三种技术的组合），以提高检测灵敏度，用于测定可溶性和总磷的细模式颗粒，由于低负荷经常遇到这种颗粒大小的部分。所获得的数据应用于调查这些地区磷的主要来源、矿物粉尘、生物质燃烧等来源的作用;人为燃烧气溶胶对环境的影响;物种形成（有机和无机成分）、溶解度、生物利用度、大气处理以及这些地区磷的季节性变化。此外，应采用区域沙尘模式模拟，以更好地描述这些区域的气溶胶输送和沉积。所得结果将有助于海洋-大气组合模式和理解控制大气磷在海洋中归宿的关键因素。

Macro-nutrients such as phosphorous are required for the growth of oceanic microorganisms such as phytoplankton that sustain the oceans food chain and biology. On the other hand, phytoplankton species emit climate-relevant organic compounds, e.g, DMS to the atmosphere that can be oxidized to sulphuric acid, which may subsequently lead to the formation of new particles that can act as cloud condensation nuclei. Information about phosphorus availability to these microorganisms is, thus, very important for the understanding of the ocean-atmosphere interactions. Atmospheric deposition is the main source of phosphorus to the open ocean; however, information about atmospheric phosphorus concentration fluxes, bioavailability and sources which is necessary to understand their fate in the oceans especially in the regions of the tropical North and South-eastern Atlantic is still needed. The few available data are mainly short-term cruise measurements which are limited in their application to the understanding of seasonal cycles and long-term predictions. To improve our knowledge on the sources and factors controlling phosphorus availability and bioavailability in these oceanic regions, long-term measurements of atmospheric phosphorus in both size-resolved and bulk aerosol particles shall be performed. Furthermore, analytical methods will be developed and optimized (based on the combination of three techniques) to enhance the detection sensitivity for the determination of soluble and total phosphorus in fine mode particles due to the low loadings often encountered in this particle size fraction. The acquired data shall be used to investigate the main sources of phosphorus in these regions, the role of sources such as mineral dust, biomass burning; anthropogenic combustion aerosols on the; speciation (organic and inorganic composition), solubility, bioavailability, atmospheric processing, and the seasonal variation of phosphorus in these regions. In addition, a regional dust model simulation shall be applied to better describe the aerosol transport and deposition in these regions. The obtained results will be useful for combined ocean-atmosphere models and the understanding of the key factors controlling the fate of atmospheric phosphorus in the oceans.