Organic complexation of iron by strong ligands and siderophores in the eastern tropical North Pacific oxygen deficient zone
Organic complexation of iron by strong ligands and siderophores in the eastern tropical North Pacific oxygen deficient zone
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热带北太平洋东部缺氧区强配体和铁载体对铁的有机络合
DOI：
10.1016/j.marchem.2021.104021
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发表时间：
2021
期刊：
影响因子：
3
通讯作者：
Bundy, Randelle M.
中科院分区：
文献类型：
--
作者：
Moore, Laura E.;Heller, Maija I.;Barbeau, Katherine A.;Moffett, James W.;Bundy, Randelle M.
大陆边缘是海洋环境中溶解铁的重要外部来源。然而，负责溶解铁离岸运输的机制受到由此产生的铁形态的影响。我们对东部热带北太平洋 (ETNP) 缺氧区 (ODZ) 的铁形态进行了表征，包括溶解铁、有机铁结合配体和还原铁。采用竞争性配体交换吸附阴极溶出伏安法 (CLE-ACSV) 和液相色谱电喷雾电离质谱 (LC-ESI-MS) 测量有机铁结合配体，以探讨有机配体对该地区溶解铁 (dFe T) 和铁 (II) 生物地球化学的影响。所有位置的有机配体均以高浓度 (1.06–5.30 nmol L− 1) 存在，并且超过了溶解铁浓度 (0.36–4.52 nmol L− 1)。铁结合强度（log K FeL、Fe' cond）范围为 11.22 至 12.75，并且在 ODZ 层中相对于含氧水柱而言有所升高。 LC-ESI-MS 显示在所有分析的样品中都存在铁载体或细菌产生的具有高 Fe 亲和力的有机配体，这表明尽管环境 dFe T 浓度较高，但这些化合物可能是由 ODZ 中的微生物产生的。这项研究是迄今为止首次对 ODZ 环境中的铁载体进行表征，发现的三种铁载体（两性霉素 B、聚胞菌素 c9、聚胞菌素 c10）可能有助于观察到 ODZ 中配体 log K FeL、Fe' cond 的升高。对其他低氧环境中有机配体 log K FeL、Fe' cond 值的比较分析表明，包括铁载体在内的强配体可能存在于其他低氧区域。在陆架到近海铁运输机制的简单模型中，强有机铁结合配体对 ODZ 中铁的寿命和运输有很大影响。这些结果表明，有机配体组成可以影响 ETNP ODZ 中的铁分布，并调节铁向公海的近海运输。
Continental margins are an important external source of dissolved iron to the marine environment. However, the mechanisms responsible for the offshore transport of dissolved iron is impacted by the resulting iron speciation. We characterized the iron speciation in the Eastern Tropical North Pacific (ETNP) oxygen deficient zone (ODZ), including dissolved iron, organic iron-binding ligands, and reduced iron. Organic iron-binding ligands were measured using both competitive ligand exchange adsorptive cathodic stripping voltammetry (CLE-ACSV) and liquid chromatography electrospray ionization mass spectrometry (LC-ESI-MS) in order to explore the impact of organic ligands on dissolved iron (dFe T) and iron (II) biogeochemistry in the region. Organic ligands were present in high concentrations (1.06–5.30 nmol L− 1) and exceeded dissolved iron concentrations (0.36–4.52 nmol L− 1) at all locations. Iron-binding strengths (log K FeL, Fe′ cond) ranged 11.22 to 12.75 and were elevated in the ODZ layer relative to the oxygenated water column. LC-ESI-MS revealed the presence of siderophores, or bacterially-produced organic ligands with high Fe-affinity, in all samples analyzed, suggesting these compounds may be produced by microbes in the ODZ despite high ambient dFe T concentrations. This study is the first to characterize siderophores in an ODZ environment to date, and the three siderophores found (amphibactin B, synechobactin c9, synechobactin c10) could contribute to the observed elevated log K FeL, Fe′ cond of ligands in the ODZ. Comparative analysis of organic ligand log K FeL, Fe′ cond values in other low oxygen environments suggests that strong ligands, including siderophores, could be present in other low oxygen regions. In a simple model of the shelf-to-offshore iron transport mechanism, strong organic iron-binding ligands had a large impact on the longevity and transport of iron in the ODZ. These results suggest that organic ligand composition can have an impact on iron distributions in the ETNP ODZ and regulate the offshore transport of iron to the open ocean.
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影响因子：
18.3
作者：
F. Scholz;J. McManus;A. Mix;C. Hensen;R. Schneider
通讯作者：
F. Scholz;J. McManus;A. Mix;C. Hensen;R. Schneider
影响因子：
5.2
作者：
A. Tagliabue;O. Aumont;L. Bopp
通讯作者：
A. Tagliabue;O. Aumont;L. Bopp
配体交换动力学与 CLE-AdCSV 测量海水中铁形态的相关性
影响因子：
3
作者：
L. M. Laglera;M. Filella
通讯作者：
M. Filella
秘鲁附近热带南太平洋东部最低氧区的铁形态
影响因子：
4.5
作者：
J. Vedamati;T. Goepfert;J. Moffett
通讯作者：
J. Moffett
影响因子：
11.4
作者：
M. Lohan;K. Bruland
通讯作者：
M. Lohan;K. Bruland