Dissolved reactive manganese at pelagic redoxclines (part II): Hydrodynamic conditions for accumulation
Dissolved reactive manganese at pelagic redoxclines (part II): Hydrodynamic conditions for accumulation
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DOI：
10.1016/j.jmarsys.2011.08.007
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发表时间：
2012-02-01
影响因子：
2.8
通讯作者：
Umlauf, Lars
中科院分区：
文献类型：
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作者：
Dellwig, Olaf;Schnetger, Bernhard;Umlauf, Lars
在波罗的海的两个缺氧深度(陆地深和哥特兰盆地)和两个季节性缺氧的淡水湖(德国的达戈湖和福奇斯库尔湖)的氧化还原跃层上测定了溶解活性锰(DMN(REACT))。这种DMN(反应)组分在氧气气氛下被迅速氧化，并被认为主要由Mn(III)组成。DMN(REACT)从外部区域向陆地深部中部明显增加。虽然哥特兰盆地中MnO(X)粒子的存在证明了还原的Mn物种正在被氧化，但几乎没有检测到DMN(反应)。由于完全不同的锰氧化过程似乎相当不可能，我们认为海洋性质是原因之一。哥特兰盆地的侧向洋流和侵入似乎阻止了稳定的亚缺氧带的形成，这是DMN(反应)积累的先决条件。这种微扰提供了微量的O(2)和H(2)S，导致DMN的立即氧化/还原(反应)或其稳定配体的劣化。在大戈湖也测得DMN(REACT)，由于该湖稳定的层化，DMN(REACT)的值大大超过了陆地深部的水平。相比之下，H(2)S出现在整个水柱和一个pH
Dissolved reactive Mn (dMn(react)) has been determined at the redoxclines of two anoxic deeps from the Baltic Sea (Landsort Deep and Gotland Basin) and two seasonally anoxic freshwater lakes (Lake Dagow and Fuchskuhle, Germany). This dMn(react) fraction is rapidly oxidised under oxygen atmosphere and is assumed to consist predominantly of Mn(III). There is a distinct increase of dMn(react) from the outer regions towards the central part of the Landsort Deep. Although the presence of MnO(x) particles in the Gotland Basin is evidence of ongoing oxidation of reduced Mn species, almost no dMn(react) was detected. Since completely different processes of Mn oxidation appear rather unlikely, we suggest oceanographic properties are responsible. Lateral currents and intrusions in the Gotland Basin seem to prevent the formation of a stable suboxic zone, a prerequisite necessary for accumulation of dMn(react). Such perturbations supply trace amounts of O(2) and H(2)S, causing either immediate oxidation/reduction of dMn(react) or deterioration of its stabilising ligands. dMn(react) has also been determined in Lake Dagow with values significantly exceeding the level of the Landsort Deep due to stable stratification of this lake. In contrast, H(2)S appearance throughout the entire water column and a pH