Changes in iron speciation following a Saharan dust event in the tropical North Atlantic Ocean


Rijkenberg, Micha J.A., Powell, Claire F., Dall'Osto, Manuel, Nielsdottir, Maria C., Patey, Matthew D., Hill, Polly G., Baker, Alex R., Jickells, Tim D., Harrison, Roy M. and Achterberg, Eric P. (2008) Changes in iron speciation following a Saharan dust event in the tropical North Atlantic Ocean. Marine Chemistry, 110, (1-2), 56-67. (doi:10.1016/j.marchem.2008.02.006).

Download

Full text not available from this repository.

Description/Abstract

Concentrations of dissolved iron (DFe) and Fe-binding ligands were determined in the tropical Northeast Atlantic Ocean (12–30°N, 21–29°W) as part of the UK-SOLAS (Surface Ocean Lower Atmosphere Study) cruise Poseidon 332 (P332) in January–February 2006. The surface water DFe concentrations varied between 0.1 and 0.4 nM with an average of 0.22 ± 0.05 nM (n = 159). The surface water concentrations of total Fe-binding ligands varied between 0.82 and 1.46 nM with an average of 1.11 ± 0.14 nM (n = 33). The concentration of uncomplexed Fe-binding ligands varied between 0.64 and 1.35 nM with an average of 0.90 ± 0.14 nM (n = 33). Thus, on average 81% of the total Fe-binding ligand concentration was uncomplexed. The average logarithmic conditional stability constant of the pool of Fe-binding ligands was 22.85 ± 0.38 with respect to Fe3+ (n = 33). A transect (12°N, 26°W to 16°N, 25.3°W) was sailed during a small Saharan dust event and repeated a week later. Following the dust event, the concentration of DFe increased from 0.20 ± 0.026 nM (n = 125) to 0.25 ± 0.028 (n = 17) and the concentration of free Fe-binding ligands decreased from 1.15 ± 0.15 (n = 4) to 0.89 ± 0.10 (n = 4) nM. Furthermore, the logarithmic stability constants of the Fe-binding ligands south of the Cape Verde islands were distinctively lower than north of the islands. The absence of a change in the logarithmic stability constant after the dust event south of the Cape Verde islands suggests that there was no significant atmospheric input of new Fe-binding ligands during this dust event.

Item Type: Article
Additional Information: Actually deposited by Jane Conquer
ISSNs: 0304-4203 (print)
Keywords: atmospheric input, aerosols, saharan dust, dry deposition, dissolved iron, organic iron complexation, equatorial atlantic ocean
Subjects: G Geography. Anthropology. Recreation > GC Oceanography
Q Science > QD Chemistry
Q Science > QR Microbiology
Divisions: University Structure - Pre August 2011 > School of Ocean & Earth Science (SOC/SOES)
ePrint ID: 52016
Date Deposited: 03 Jun 2008
Last Modified: 27 Mar 2014 18:35
URI: http://eprints.soton.ac.uk/id/eprint/52016

Actions (login required)

View Item View Item