The stabilisation and transportation of dissolved iron from high temperature hydrothermal vent systems

Hawkes, Jeffrey A.; Gledhill, Martha; Connelly, Douglas P.; Achterberg, Eric P.. 2013 The stabilisation and transportation of dissolved iron from high temperature hydrothermal vent systems. Earth and Planetary Science Letters, 375. 280-290. 10.1016/j.epsl.2013.05.047

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Abstract/Summary

Iron (Fe) binding phases in two hydrothermal plumes in the Southern Ocean were studied using a novel voltammetric technique. This approach, reverse titration–competitive ligand exchange–adsorptive cathodic stripping voltammetry, showed that on average 30±21% of dissolved Fe in the hydrothermal plumes was stabilised by chemically labile binding to ligands. The conditional stability constant (log K′FeL) of the observed complexes was 20.61±0.54 (mean±1 SD) for the two vent sites, intermediate between previous measurements of deep ocean ligands (21.4–23; Kondo et al., 2012) and dissolved weak estuarine ligands (<20; Gerringa et al., 2007). Our results indicate that approximately 7.5% of all hydrothermal Fe was stabilised by complexation with ligands. Furthermore, 47±26% of the dissolved Fe in the plume existed in the colloidal size range (0.02–0.2 µm). Our data suggests that a portion (∼7.5%) of hydrothermal Fe is sufficiently stabilised in the dissolved size fraction (<0.2 µm) to make an important impact on deep ocean Fe distributions. Lateral deep ocean currents transport this hydrothermal Fe as lenses of enhanced Fe concentrations away from mid ocean ridge spreading centres and back arc basins.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.1016/j.epsl.2013.05.047
Programmes:	NOC Programmes
ISSN:	0012-821X
Date made live:	12 Jun 2013 15:08 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/502232

Item Type:

Publication - Article

Digital Object Identifier (DOI):

10.1016/j.epsl.2013.05.047

Programmes:

NOC Programmes

ISSN:

0012-821X

Date made live:

12 Jun 2013 15:08 +0 (UTC)

URI:

https://nora.nerc.ac.uk/id/eprint/502232