GLORIA

GEOMAR Library Ocean Research Information Access

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
Document type
Publisher
Years
  • 1
    facet.materialart.
    Unknown
    Characterisation of iron binding ligands in seawater by reverse titration (2013)
    Elsevier
    In:  Analytica Chimica Acta, 766 . pp. 53-60.
    Details
    Publication Date: 2017-10-24
    Description: Here we demonstrate the use of reverse titration - competitive ligand exchange-adsorptive cathodic stripping voltammetry (RT-CLE-ACSV) for the analysis of iron (Fe) binding ligands in seawater. In contrast to the forward titration, which examines excess ligands in solution, RT-CLE-ACSV examines the existing Fe-ligand complexes by increasing the concentration of added (electroactive) ligand (1-nitroso-2-naphthol) and analysis of the proportion of Fe bound to the added ligand. The data manipulation allows the accurate characterisation of ligands at equal or lower concentrations than Fe in seawater, and disregards electrochemically inert dissolved Fe such as some colloidal phases. The method is thus superior to the forward titration in environments with high Fe and low ligand concentrations or high concentrations of inert Fe.We validated the technique using the siderophore ligand ferrioxamine B, and observed a stability constant K'Fe3+FoB of 0.74-4.37×1021mol-1, in agreement with previous results. We also successfully analysed samples from coastal waters and a deep ocean hydrothermal plume. Samples from these environments could not be analysed with confidence using the forward titration, highlighting the effectiveness of the RT-CLE-ACSV technique in waters with high concentrations of inert Fe. © 2013 Elsevier B.V.
    Type: Article , PeerReviewed
    Format: text
    DOI: 10.1016/j.aca.2012.12.048
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 2
    facet.materialart.
    Unknown
    The stabilisation and transportation of dissolved iron from high temperature hydrothermal vent systems (2013)
    Elsevier
    In:  Earth and Planetary Science Letters, 375 . pp. 280-290.
    Details
    Publication Date: 2017-10-24
    Description: 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.
    Type: Article , PeerReviewed
    Format: text
    DOI: 10.1016/j.epsl.2013.05.047
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 3
    facet.materialart.
    Unknown
    Isotopic signature of dissolved iron delivered to the Southern Ocean from hydrothermal vents in the East Scotia Sea (2017)
    Geological Society of America (GSA)
    In: Geology
    Details
    Publication Date: 2017-03-08
    Description: It has recently been demonstrated that hydrothermal vents are an important source of dissolved Fe (dFe) to the Southern Ocean. The isotopic composition ( 56 Fe) of dFe in vent fluids appears to be distinct from other sources of dFe to the deep ocean, but the evolution of 56 Fe during mixing between vent fluids and seawater is poorly constrained. Here we present the evolution of 56 Fe for dFe in hydrothermal fluids and dispersing plumes from two sites in the East Scotia Sea. We show that 56 Fe values in the buoyant plume are distinctly lower (as low as –1.19) than the hydrothermal fluids (–0.29), attributed to (1) precipitation of Fe sulfides in the early stages of mixing, and (2) partial oxidation of Fe(II) to Fe(III), 〉55% of which subsequently precipitates as Fe oxyhydroxides. By contrast, the 56 Fe signature of stabilized dFe in the neutrally buoyant plume is –0.3 to –0.5. This cannot be explained by continued dilution of the buoyant plume with background seawater; rather, we suggest that isotope fractionation of dFe occurs during plume dilution due to Fe ligand complexation and exchange with labile particulate Fe. The 56 Fe signature of stabilized hydrothermal dFe in the East Scotia Sea is distinct from background seawater and may be used to quantify the hydrothermal dFe input to the ocean interior.
    Print ISSN: 0091-7613
    Electronic ISSN: 1943-2682
    Topics: Geosciences
    Published by Geological Society of America (GSA)
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...