Evidence of an extensive spread of hydrothermal dissolved iron in the Indian Ocean

Nishioka, Jun; Obata, Hajime; Tsumune, Daisuke

doi:10.1016/j.epsl.2012.11.040

Cited by 118 publications

(93 citation statements)

References 43 publications

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“…Reduction of Fe(III) to Fe(II) with possible stabilization by organic ligands is a potential mechanism by which Fe is made more bioavailable to phytoplankton (Anderson and Morel, 1980;Maldonado and Price, 2001). The release of Fe(II) from reducing continental-margin sediments (Hong and Kester, 1986;Lohan and Bruland, 2008) as well as Fe(II) supply from seafloor hydrothermal vents (Bennett et al, 2008;Toner et al, 2009;Tagliabue et al, 2010;Wu et al, 2011a;Nishioka et al, 2013;Vedamati et al, 2014) are now recognized as possible sources of Fe(II) in seawater. Under anoxic conditions as those encountered in relatively organic-rich marine sediments, when sulfide generation is limited and thus precluding the precipitation of FeS minerals reductive dissolution of Fe oxides or clay minerals can result in dissolved Fe(II) concentrations up to 1 mM (Sell and Morse, 2006).…”

Section: Introductionmentioning

confidence: 98%

Total dissolvable and dissolved iron isotopes in the water column of the Peru upwelling regime

Chever

Rouxel

Croot

et al. 2015

Geochimica et Cosmochimica Acta

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Vertical distributions of iron (Fe) concentrations and isotopes were determined in the total dissolvable and dissolved pools in the water column at three coastal stations located along the Peruvian margin, in the core of the Oxygen Minimum Zone (OMZ). The shallowest station 121 (161 m total water depth) was characterized by lithogenic input from the continental plateau, yielding concentrations as high as 456 nM in the total dissolvable pool. At the 2 other stations (stations 122 and 123), Fe concentrations of dissolved and total dissolvable pools exhibited maxima in both surface and deep layers. Fe isotopic composition (d 56 Fe) showed a fractionation toward lighter values for both physical pools throughout the water column for all stations with minimum values observed for the surface layer (between À0.64 and À0.97& at 10-20 m depth) and deep layer (between À0.03 and À1.25& at 160-300 m depth). An Fe isotope budget was established to determine the isotopic composition of the particulate pool. We observed a range of d 56 Fe values for particulate Fe from +0.02 to À0.87&, with lightest values obtained at water depth above 50 m. Such light values in the both particulate and dissolved pools suggest sources other than atmospheric dust deposition in the surface ocean, including lateral transport of isotopically light Fe. Samples collected at station 122 closest to the sediment show the lightest isotope composition in the dissolved and the particulate pools (À1.25 and À0.53& respectively) and high Fe(II) concentrations (14.2 ± 2.1 nM) consistent with a major reductive benthic Fe sources that is transferred to the ocean water column. A simple isotopic model is proposed to link the extent of Fe(II) oxidation and the Fe isotope composition of both particulate and dissolved Fe pools. This study demonstrates that Fe isotopic composition in OMZ regions is not only affected by the relative contribution of reductive and non-reductive shelf sediment input but also by seawater-column processes during the transport and oxidation of Fe from the source region to open seawater.

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Section: Introductionmentioning

confidence: 98%

Total dissolvable and dissolved iron isotopes in the water column of the Peru upwelling regime

Chever

Rouxel

Croot

et al. 2015

Geochimica et Cosmochimica Acta

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“…Indeed, a synthesis study suggests a significant number of ridge systems remain to be discovered in the Southern Ocean, pointing out that only eight sites have been recorded along the approximately 20 000 km ridge system around Antarctica [45]. Apart from one study near the Bouvet Triple junction [17], much of our understanding of the broader biogeochemical impacts of hydrothermal vents on the ocean Fe cycle comes from studies that have taken place in the Atlantic [20,21], Pacific [24] and Indian [46] Oceans. As discussed in §4a, it is important to consider how generalized these inferences are for ridges in the Southern Ocean, which we have demonstrated to be the main driver of the carbon cycle response.…”

Section: (B) Relative Importance Of Different Ridge Systemsmentioning

confidence: 99%

Impact of hydrothermalism on the ocean iron cycle

Tagliabue

2016

Phil. Trans. R. Soc. A.

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As the iron supplied from hydrothermalism is ultimately ventilated in the iron-limited Southern Ocean, it plays an important role in the ocean biological carbon pump. We deploy a set of focused sensitivity experiments with a state of the art global model of the ocean to examine the processes that regulate the lifetime of hydrothermal iron and the role of different ridge systems in governing the hydrothermal impact on the Southern Ocean biological carbon pump. Using GEOTRACES section data, we find that stabilization of hydrothermal iron is important in some, but not all regions. The impact on the Southern Ocean biological carbon pump is dominated by poorly explored southern ridge systems, highlighting the need for future exploration in this region. We find inter-basin differences in the isopycnal layer onto which hydrothermal Fe is supplied between the Atlantic and Pacific basins, which when combined with the inter-basin contrasts in oxidation kinetics suggests a muted influence of Atlantic ridges on the Southern Ocean biological carbon pump. Ultimately, we present a range of processes, operating at distinct scales, that must be better constrained to improve our understanding of how hydrothermalism affects the ocean cycling of iron and carbon. This article is part of the themed issue ‘Biological and climatic impacts of ocean trace element chemistry’.

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“…There is now also mounting evidence that high-temperature vents are a major contributor to the dissolved Fe inventory of the deep ocean (e.g., Chu et al, 2006;Bennett et al, 2008;Tagliabue et al, 2010;Wu et al, 2011;Nishioka et al, 2013;Hawkes et al, 2013;Saito et al, 2013). Iron stabilisation and dispersion occurs through Fe-ligand complex and aggregate formation (Sander and Koschinsky, 2011;Hawkes et al, 2013) and the dispersion of pyrite nanoparticles over large distances in the deep ocean (Yücel et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

Hydrothermal sediments are a source of water column Fe and Mn in the Bransfield Strait, Antarctica

Aquilina¹,

Homoky²,

Hawkes³

et al. 2014

Geochimica et Cosmochimica Acta

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Please cite this article as: Aquilina, A., Homoky, W.B., Hawkes, J.A., Lyons, T.W., Mills, R.A., Hydrothermal sediments are a source of water column Fe and Mn in the Bransfield Strait, Antarctica, Geochimica et Cosmochimica Acta (2014), doi: http://dx.doi.org/10.1016/j.gca. 2014.04.003 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

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Evidence of an extensive spread of hydrothermal dissolved iron in the Indian Ocean

Cited by 118 publications

References 43 publications

Total dissolvable and dissolved iron isotopes in the water column of the Peru upwelling regime

Total dissolvable and dissolved iron isotopes in the water column of the Peru upwelling regime

Impact of hydrothermalism on the ocean iron cycle

Hydrothermal sediments are a source of water column Fe and Mn in the Bransfield Strait, Antarctica

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