PHOsphorus Speciation in mineral Dust and Marine Aerosol Particles

• Applicant: Dr. Khanneh Wadinga Fomba
• Subject Area: Atmospheric Science
• Term: from 2017 to 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 378783753

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.

• DFG Programme: Research Grants
• Cooperation Partners: Professor Dr. Eric Achterberg; Dr. Bernd Heinold; Dr. Jost Valentin Lavric; Professorin Dr. Kerstin Schepanski