Iron geochemistry in surface sediments of a temperate semi-enclosed bay, North China
Iron geochemistry in surface sediments of a temperate semi-enclosed bay, North China
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DOI：
10.1016/j.ecss.2015.08.018
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发表时间：
2015-11
影响因子：
2.8
通讯作者：
Mao‐Xu Zhu;Xiang-Li Huang;Guipeng Yang;Liang-Jin Chen
中科院分区：
文献类型：
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作者：
Mao‐Xu Zhu;Xiang-Li Huang;Guipeng Yang;Liang-Jin Chen
定量分析了胶州湾半封闭海域表层沉积物中铁（Fe）的形态和微生物可还原铁（III）氧化物（MR-Fe(III)），揭示了受人为扰动环境下的铁地球化学特征。结果表明，海湾沉积铁主要为自然风化源，没有明显的人为输入，总铁与铝呈良好的线性耦合关系。在三个高活性的Fe(III) （Fe(III)HR）池中，良好结晶的Fe（III）氧化物（Fe(III)wc）始终是主要相，其次是不良结晶的Fe（III）氧化物（Fe(III)pc），无定形的Fe（III）氧化物（Fe(III)am）的重要性较小。沉积物中未硫化铁（II）的优势大于硫化铁（II），这表明微生物铁（III）还原（MIR）在自由硫化物匮乏条件下的重要性。与海湾其他地区相比，高TOC河流输入导致Fe(III) hrh与总有机碳（TOC）比值异常。与om相关的MIR作为共同驱动力使得所有含Fe（II）的相与TOC线性耦合。表层沉积物中的MR-Fe（III）覆盖了所有的Fe（III）和一小部分较不活泼的Fe（III）相，而Fe（III）最多只是一个次要的贡献者。在温带半封闭海湾中，高活性铁似乎在一定程度上富集，就像在湿热带海湾中一样。
Iron (Fe) speciation and microbial reducible Fe(III) oxides (MR-Fe(III)) in surface sediments of semi-enclosed Jiaozhou Bay were quantified to reveal Fe geochemistry in the settings subjected to anthropogenic perturbations. Results indicate that sedimentary Fe in the bay is mainly of natural weathering source, without appreciable anthropogenic Fe inputs, as indicated by a generally good linear coupling of total Fe to aluminum. Among the three highly reactive Fe(III) (Fe(III)HR) pools, well crystalline Fe(III) oxides (Fe(III)wc) were always the predominant phase, followed by poorly crystalline Fe(III) oxides (Fe(III)pc), and amorphous Fe(III) oxides (Fe(III)am) were only of minor importance. The dominance of non-sulfidized Fe(II) over sulfidized Fe in the sediments points to the importance of microbial iron(III) reduction (MIR) in the free sulfide-starved conditions. High riverine inputs of TOC leads to outliers in the Fe(III)HRversus total organic carbon (TOC) ratio compared the rest of the bay. OM-dependent MIR as the common driving force has rendered all Fe(II)-bearing phases linearly coupled to TOC. MR-Fe(III) in the surface sediments covered all Fe(III)amand a fraction of less reactive Fe(III) phases, while Fe(III)wcwas at most a minor contributor. Highly reactive Fe appears to be enriched to some extent in the temperate semi-enclosed bay, as in the wet-tropical counterparts.