Estimation of the atmospheric flux of nutrients and trace metals to the Eastern Tropical North Atlantic Ocean

Powell, Claire, Baker, Alex ORCID:, Jickells, Tim, Bange, Hermann, Chance, Rosemary and Yodle, Chan (2015) Estimation of the atmospheric flux of nutrients and trace metals to the Eastern Tropical North Atlantic Ocean. Journal of the Atmospheric Sciences, 72 (10). 4029–4045. ISSN 0022-4928

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Atmospheric deposition contributes potentially significant amounts of the nutrients iron, nitrogen and phosphorus (via mineral dust and anthropogenic aerosols) to the oligotrophic tropical North Atlantic Ocean. Transport pathways, deposition processes and source strengths contributing to this atmospheric flux are all highly variable in space and time. Atmospheric sampling was conducted during 28 research cruises through the Eastern Tropical North Atlantic (ETNA) over a 12 year period and a substantial dataset of measured concentrations of nutrients and trace metals in aerosol and rainfall over the region was acquired. This database was used to quantify (on a spatial- and seasonal-basis) the atmospheric input of ammonium, nitrate, soluble phosphorus and soluble and total iron, aluminium and manganese to the ETNA. The magnitude of atmospheric input varies strongly across the region, with high rainfall rates associated with the Inter-tropical Convergence Zone contributing to high wet deposition fluxes in the south, particularly for soluble species. Dry deposition fluxes of species associated with mineral dust exhibited strong seasonality, with highest fluxes associated with winter-time low-level transport of Saharan dust. Overall (wet plus dry) atmospheric inputs of soluble and total trace metals were used to estimate their soluble fractions. These also varied with season and were generally lower in the dry north than in the wet south. The ratio of ammonium plus nitrate to soluble iron in deposition to the ETNA was lower than the N:Fe requirement for algal growth in all cases, indicating the importance of the atmosphere as a source of excess iron.

Item Type: Article
Additional Information: This article is licensed under a Creative Commons Attribution 4.0 license.
Faculty \ School: Faculty of Science > School of Environmental Sciences
Faculty of Science > School of Natural Sciences
University of East Anglia Research Groups/Centres > Theme - ClimateUEA
Faculty of Science
UEA Research Groups: Faculty of Science > Research Groups > Centre for Ocean and Atmospheric Sciences
Depositing User: Pure Connector
Date Deposited: 16 Oct 2015 09:01
Last Modified: 18 Jul 2024 00:26
DOI: 10.1175/JAS-D-15-0011.1


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