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

Herbert, R.J., Krom, M., Carslaw, K.S., Stockdale, A., Mortimer, R.J.G. ORCID: 0000-0003-1292-8861, Benning, L., Pringle, J.K. and Browse, J., 2018. The effect of atmospheric acid processing on the global deposition of bioavailable phosphorus from dust. Global Biogeochemical Cycles. ISSN 0886-6236 (Forthcoming)

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Abstract

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 aditional 16.9 Gg-P yr from acid dissolution of apatite in the atmosphere, representing an increase of 120%. The North Atlantic, north west 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: Journal article
Publication Title: Global Biogeochemical Cycles
Creators: Herbert, R.J., Krom, M., Carslaw, K.S., Stockdale, A., Mortimer, R.J.G., Benning, L., Pringle, J.K. and Browse, J.
Publisher: Wiley-Blackwell
Date: 20 August 2018
ISSN: 0886-6236
Identifiers:
NumberType
10.1029/2018GB005880DOI
Divisions: Schools > School of Animal, Rural and Environmental Sciences
Depositing User: Linda Sullivan
Date Added: 13 Aug 2018 10:54
Last Modified: 11 Sep 2018 10:21
URI: http://irep.ntu.ac.uk/id/eprint/34322

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