Atmospheric P deposition to the subtropical North Atlantic: sources, properties, and relationship to N deposition.

Zamora, Lauren, Prospero, J. M., Hansell, D. A. and Trapp, J. M. (2013) Atmospheric P deposition to the subtropical North Atlantic: sources, properties, and relationship to N deposition. Open Access Journal of Geophysical Research: Atmospheres, 118 . pp. 1-17. DOI 10.1002/jgrd.50187.

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Abstract

Biogeochemical studies show that the surface waters of the subtropical North Atlantic are highly phosphorus (P) stressed. Human activity may exacerbate phosphorus stress by enhancing atmospheric nitrogen (N) deposition and raising N/P ratios in deposition. However, the magnitude of this effect is unclear, in part, because atmospherically deposited phosphorus sources are not well known, particularly the contribution from organic phosphorus. Here we report measurements of phosphorus in aerosols and wet deposition at Miami and Barbados. African dust is the major aerosol P source at both Miami and Barbados, containing ~880 ppm total phosphorus and ~70 ppm soluble reactive phosphorus (SRP). Organic compounds contribute, on average, 28%–44% of soluble phosphorus in precipitation. Because of dust transport seasonality, phosphorus inputs to the North Atlantic are expected to be highly variable with 2–10 times more P deposition during summer than winter. Pollution is also an important contributor to total and soluble phosphorus in Miami aerosols and deposition. Estimated SRP deposition in Barbados and Miami is 0.21 and 0.13 µmol m−2 d−1 phosphorus, respectively. Inorganic nitrogen in excess of Redfield ratio expectations in deposition was very different between the sites, totaling 21–30 and 127–132 µmol m−2 d−1 nitrogen in Barbados and Miami, respectively; the high deposition rates at Miami are linked to pollutants. Including soluble organic nitrogen and phosphorus halved the estimates of excess nitrogen in Barbados wet deposition. Thus, the organic phosphorus fraction is important in the assessment of the magnitude of biogeochemical change of the North Atlantic caused by atmospheric deposition.

Document Type: Article
Additional Information: WOS:000317839700030
Keywords: aerosols, phosphorus, nitrogen, deposition; DISSOLVED ORGANIC PHOSPHORUS; LONG-RANGE TRANSPORT; MEDITERRANEAN SEA; NITROGEN DEPOSITION; AEROSOL-PARTICLES; LEVANTINE BASIN; NATURAL-WATERS; MINERAL DUST; OCEAN; PHOSPHATE; aerosol chemistry, phosphorus, deposition, nitrogen, North Atlantic
Research affiliation: OceanRep > GEOMAR > FB2 Marine Biogeochemistry > FB2-BM Biogeochemical Modeling
Refereed: Yes
Open Access Journal?: No
DOI etc.: 10.1002/jgrd.50187
ISSN: 2169-8996
Date Deposited: 21 Mar 2013 13:05
Last Modified: 06 Feb 2018 13:22
URI: http://oceanrep.geomar.de/id/eprint/20736

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