The effect of atmospheric acid processing on the global deposition of bioavailable phosphorus from dust

Herbert, R. J., Krom, M. D., Carslaw, K. S., Stockdale, A., Mortimer, R. J. G., Benning, L. G., Pringle, K. and Browse, J. (2018) The effect of atmospheric acid processing on the global deposition of bioavailable phosphorus from dust. Global Biogeochemical Cycles, 32 (9). pp. 1367-1385. ISSN 1944-9224 doi: 10.1029/2018GB005880

Abstract/Summary

The role of dust as a source of bioavailable phosphorus (Bio-P) is quantified using a new parameterization for apatite dissolution in combination with global soil data maps and a global aerosol transport model. Mineral dust provides 31.2 Gg P yr-1 of Bio-P to the oceans, with 14.3 Gg P yr-1 from labile P present in the dust, and an additional 16.9 Gg P yr 1 from acid dissolution of apatite in the atmosphere, representing an increase of 120%. The North Atlantic, northwest Pacific, and Mediterranean Sea are identified as important sites of Bio-P deposition from mineral dust. The acid dissolution process increases the fraction of total P that is bioavailable from ~10% globally from the labile pool to 23% in the Atlantic Ocean, 45% in the Pacific Ocean, and 21% in the Indian Ocean, with an ocean global mean value of 22%. Strong seasonal variations, especially in the North Pacific, northwest Atlantic, and Indian Ocean, are driven by large-scale meteorology and pollution sources from industrial and biomass burning regions. Globally constant values of total P content and bioavailable fraction used previously do not capture the simulated variability. We find particular sensitivity to the representation of particle-to-particle variability of apatite, which supplies Bio-P through acid-dissolution, and calcium carbonate, which helps to buffer the dissolution process. A modest 10% external mixing results in an increase of Bio-P deposition by 18%. The total Bio-P calculated here (31.2 Gg P yr-1) represents a minimum compared to previous estimates due to the relatively low total P in the global soil map used.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/78744
Identification Number/DOI	10.1029/2018GB005880
Refereed	Yes
Divisions	Science > School of Mathematical, Physical and Computational Sciences > Department of Meteorology
Publisher	American Geophysical Union
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