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首页> 外文期刊>Estuarine Coastal and Shelf Science >Electrode measurements of the oxidation reduction potential in the Gotland Deep using a moored profiling instrumentation
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Electrode measurements of the oxidation reduction potential in the Gotland Deep using a moored profiling instrumentation

机译：使用系泊轮廓分析仪对哥特兰深部的氧化还原电位进行电极测量

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The Gotland Deep Environmental Sampling Station (GODESS) operating between 30 m and 185 m was used to assess the variation of in situ redox potential (E_h) in the stratified water column of the central Baltic Sea, for a period of 56 days (November 2010-January 2011). The aim of this study was to acquire in-depth understanding of redox variations with the overall objective to identify the processes controlling E-h. At an interval of 8 h basic hydro-physical parameters were registered, including the oxidation-reduction potential, dissolved oxygen, chlorophyll a fluorescence, turbidity, temperature and conductivity. In total 170 profiles of all parameters were obtained. The measured E_h (with respect to standard hydrogen electrode, SHE) ranged from -0.055 V to 0.167 V: After temperature and pH correction of the standard reduction potentials, a comparison of the measured E_h, with that calculated for the particular redox couples was carried out by applying the Nernst-equation. Furthermore, the concentrations of the most important redox elements such as Fe, Mn, N, O, C and S used for comparison were estimated by using empirical functions or were based on measurements of discrete water samples, taken at the time of deployment and recovery of the mooring. The obtained results reveal that the reduction of Fe(Ⅲ) and O_2 may be the main processes controlling the E_h, potential in the Gotland basin. Below the redoxcline the reduction of hematite and then ferric oxyhydroxide could be related to the redox potential and somewhat deeper Fe(Ⅲ)/Fe(Ⅱ) was found to be the dominant redox couple. Although mixed potential theory could have been applied, the Fe couples appear to dominate over many other possible redox equilibria. This may be explained by the relatively high exchange current of Fe and by high Fe concentrations (up to 1.5 μM). Finally, a close correspondence to the E_h potentials measured in the oxic/hypoxic part of the water column was found considering the O_2/O~-_2 and the O~-_1/H_2O_2 couples. This suggests that one-electron transfer reactions determined the E_h under oxic/hypoxic conditions.
机译：哥特兰深部环境采样站（GODESS）在30 m至185 m之间运行，用于评估波罗的海中部分层水柱中原位氧化还原电势（E_h）的变化，持续56天（2010年11月） -2011年1月）。这项研究的目的是获得对氧化还原变化的深入了解，其总体目标是确定控制E-h的过程。每隔8小时记录一次基本的水物理参数，包括氧化还原电势，溶解氧，叶绿素a荧光，浊度，温度和电导率。总共获得了170个所有参数的配置文件。测得的E_h（相对于标准氢电极，SHE）在-0.055 V至0.167 V范围内：在对标准还原电位进行温度和pH校正后，将测得的E_h与针对特定氧化还原对计算出的E_h进行了比较通过应用能斯特方程此外，用于比较的最重要的氧化还原元素（如Fe，Mn，N，O，C和S）的浓度是通过经验函数估算的，或基于在部署和回收时采集的离散水样的测量值系泊。结果表明，Fe（Ⅲ）和O_2的还原可能是控制哥得兰盆地E_h势的主要过程。在氧化还原线以下，赤铁矿的还原以及羟基氧化铁的还原可能与氧化还原电位有关，并且发现较深的Fe（Ⅲ）/ Fe（Ⅱ）是主要的氧化还原对。尽管可以应用混合势能理论，但Fe对似乎在许多其他可能的氧化还原平衡中起主导作用。这可以通过较高的Fe交换电流和较高的Fe浓度（最高1.5μM）来解释。最后，考虑到O_2 / O〜-_2和O〜-_1 / H_2O_2对，发现与水柱的有氧/低氧部分测得的E_h电位非常接近。这表明单电子转移反应确定了在有氧/低氧条件下的E_h。

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