The unaccounted dissolved iron (II) sink: Insights from dFe(II) concentrations in the deep Atlantic Ocean.
The unaccounted dissolved iron (II) sink: Insights from dFe(II) concentrations in the deep Atlantic Ocean.
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未解释的溶解铁 (II) 沉降：来自大西洋深海 dFe(II) 浓度的见解。
DOI：
10.1016/j.scitotenv.2022.161179
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发表时间：
2023
期刊：
影响因子：
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通讯作者：
González-Santana D
中科院分区：
文献类型：
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作者：
González-Santana D
沿大洋中脊发现的热液喷口是许多还原的化学物种和微量元素的来源。为了确定沿大西洋中脊(在39.5°N至26°N之间)溶解铁(II)的变异性，测量了6个热液喷口上方以及没有热液活动的站点的DFE(II)浓度。非热液影响区的DFE(II)浓度范围为0.00~0.12 nmol L−1(检出限 = 0.02 ± 0.02 nol L−1)，热液羽流中DFE(II)浓度最高可达12.8 nmol L−1。海水中的铁(II)在几分钟到几小时的时间内被氧化，这平均比从深海采集样本并在船上实验室进行分析所需的时间快两倍。用多参数方程估算了深海DFE(II)的初始浓度。考虑了现场温度、pH、盐度和样品采集与分析之间的延迟。结果表明，DFE(II)在铁库中的作用比以前更显著，只占溶解铁库的>；20 %，而以前报道的铁库的<；10 %。这种差异是由于采样过程中Fe(II)的损失造成的，当时35-90 %的DFE(II)被氧化。因此，原位DFE(II)浓度大大高于在沉积和热液环境中报告的值，在这些环境中，Fe以还原形式添加到海洋中。因此，DFE(II)在热液环境中的高能动性掩盖了来自深海的DFE(II)的规模。
Hydrothermal vent sites found along mid-ocean ridges are sources of numerous reduced chemical species and trace elements. To establish dissolved iron (II) (dFe(II)) variability along the Mid Atlantic Ridge (between 39.5°N and 26°N), dFe(II) concentrations were measured above six hydrothermal vent sites, as well as at stations with no active hydrothermal activity. The dFe(II) concentrations ranged from 0.00 to 0.12 nmol L−1(detection limit = 0.02 ± 0.02 nmol L−1) in non-hydrothermally affected regions to values as high as 12.8 nmol L−1within hydrothermal plumes. Iron (II) in seawater is oxidised over a period of minutes to hours, which is on average two times faster than the time required to collect the sample from the deep ocean and its analysis in the onboard laboratory. A multiparametric equation was used to estimate the original dFe(II) concentration in the deep ocean. The in-situ temperature, pH, salinity and delay between sample collection and its analysis were considered. The results showed that dFe(II) plays a more significant role in the iron pool than previously accounted for, constituting a fraction >20 % of the dissolved iron pool, in contrast to <10 % of the iron pool formerly reported. This discrepancy is caused by Fe(II) loss during sampling when between 35 and 90 % of the dFe(II) gets oxidised. In-situ dFe(II) concentrations are therefore significantly higher than values reported in sedimentary and hydrothermal settings where Fe is added to the ocean in its reduced form. Consequently, the high dynamism of dFe(II) in hydrothermal environments masks the magnitude of dFe(II) sourced within the deep ocean.