Atmospheric phosphorus and its geochemical cycling: Fundamentals, progress, and perspectives

Abstract

Phosphorus (P) is an essential macronutrient for all organisms that can be redistributed between terrestrial and oceanic systems via atmospheric emission, transport, transformation, and deposition. Moreover, since natural P mobilization from the lithosphere to ecosystems is a relatively slow process, the role of atmospheric P seems to play an important role in its cycling. This paper provides a comprehensive review of the analytical methods used for characterizing atmospheric P species and the methods used for identifying P sources (e.g., oxygen stable isotope compositions of phosphate, δ18OP) discussing their respective suitability, advantages, and limitations. While at a regional scale δ18OP of atmospheric P are generally source-specific, at a more global scale these isotope compositions tend to overlap between sources, rendering their tracer potential more difficult. Furthermore, various sources of atmospheric P and their fluxes are compiled, and the potential uncertainties in the estimates of their respective contributions are reviewed, which suggest that more model inter-comparations, parameter optimizations, and field observations are still needed. Moreover, we summarize the long-range transport process controlling P atmospheric dispersion at various scales (focusing on dust and biomass burning). In addition, the transformation mechanism, especially acid dissolution, that modifies the P cycle during its residence time in the atmosphere is depicted. Finally, we propose that land cover may be a potential key control to the atmospheric P deposition rate based on the critical analysis of previously published rates. This review allows us to ultimately propose key recommendations for fostering future research on P geochemical cycling. © 2023