Voltammetric Investigation of Hydrothermal Iron Speciation
Voltammetric Investigation of Hydrothermal Iron Speciation
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DOI：
10.3389/fmars.2016.00075
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发表时间：
2016-01-01
影响因子：
3.7
通讯作者：
Koschinsky, Andrea
中科院分区：
文献类型：
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作者：
Kleint, Charlotte;Hawkes, Jeffrey A.;Koschinsky, Andrea
与环境海水相比，热液喷口流体高度富集铁（Fe），有机配体可能在促进一些热液Fe向公海的运输中发挥作用。这一点很重要，因为铁是世界海洋大部分地区初级生产的限制性微量营养素。采用竞争性配体交换-吸附阴极溶出伏安法（CLE-AdCSV），以水杨醛肟（SA）为人工配体，研究了南太平洋新赫布里底群岛弧科里奥利海Nifonea喷流区喷流液和喷流样品中Fe的浓度和形态。我们的研究结果总溶解铁（dFe）在浮力热液羽样品显示浓度高达3.86亩M dFe只有一小部分之间的1.1和11.8%的化学不稳定。发现铁结合配体浓度（M）在μ M水平，具有强条件稳定常数，logK（FeL，Fe）（3+）为22.9。在Nifonea喷口区域上方的非浮力热液羽流中，高达84.7%的可用Fe是化学不稳定的，测得的[L]浓度高达97 nM。[L]一直超过Fe-lab，表明所有可用的铁被络合，这与非浮力羽流中的高F-lab值相结合，意味着高比例的热液dFe可能从羽流被输送到周围的沃茨，有助于全球海洋Fe预算。
Hydrothermal vent fluids are highly enriched in iron (Fe) compared to ambient seawater, and organic ligands may play a role in facilitating the transport of some hydrothermal Fe into the open ocean. This is important since Fe is a limiting micronutrient for primary production in large parts of the world's surface ocean. We have investigated the concentration and speciation of Fe in several vent fluid and plume samples from the Nifonea vent field, Coriolis Troughs, New Hebrides Island Arc, South Pacific Ocean using competitive ligand exchange-adsorptive cathodic stripping voltammetry (CLE-AdCSV) with salicylaldoxime (SA) as the artificial ligand. Our results for total dissolved Fe (dFe) in the buoyant hydrothermal plume samples showed concentrations up to 3.86 mu M dFe with only a small fraction between 1.1 and 11.8% being chemically labile. Iron binding ligand concentrations (M) were found in mu M level with strong conditional stability constants up to logK(FeL,Fe)(3+) of 22.9. Within the non-buoyant hydrothermal plume above the Nifonea vent field, up to 84.7% of the available Fe is chemically labile and [L] concentrations up to 97 nM were measured. [L] was consistently in excess of Fe-lab, indicating that all available Fe is being complexed, which in combination with high F-lab values in the non-buoyant plume, signifies that a high fraction of hydrothermal dFe is potentially being transported away from the plume into the surrounding waters, contributing to the global oceanic Fe budget.