Sub-surface iodide maxima: evidence for biologically catalyzed redox cycling in Arabian Sea OMZ during the SW intermonsoon
Sub-surface iodide maxima: evidence for biologically catalyzed redox cycling in Arabian Sea OMZ during the SW intermonsoon
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DOI：
10.1016/s0967-0645(97)00013-1
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发表时间：
1997-01-01
影响因子：
3
通讯作者：
Van der Weijden, CH
中科院分区：
文献类型：
--
作者：
Farrenkopf, AM;Luther, GW;Van der Weijden, CH
在西北印度洋索马里和阿拉伯盆地的六个剖面中，有五个剖面发现了次表层I-最大值（200-600 nM）。除了这些最大值，溶解的I-表现出正常的高（100纳米或更大）的值在表面和值范围从3至40纳米的深度，这是高于其他开放的海洋系统。硫化物一般被发现是小于2纳米的水柱，表明碘酸盐的硫化物的化学还原是不重要的调节碘形态在西北印度洋。真光层以下的这些新的高碘化物值似乎与其他大量化学或水文特征（sigma（theta））无关，但可能是两种不同的生物介导的再矿化过程的结果：（1）如在次表面最大值中所见，IO 3-直接还原为I-，以及（2）在有机物分解过程中，I-从C-I键中释放。碘标准化盐度，具体碘，没有发现在这个系统中是保守的。总的来说，我们的特定碘数据支持碘掺入表面的有机材料中。碘化物，当存在于透光层以下时，是输出的有机物质分解的产物。这些数据和过程与以前在黑海和切萨皮克湾发现的一致。然而，在西北阿拉伯海，碘和氧是可测量的整个水柱，这表明该系统是不平衡与现行的氧化还原条件和传统的热力学考虑的pE似乎不适用。孔隙水碘化物在顶部150厘米增加深度约19 μ M作为结果的I-在有机物分解过程中的释放。(C)1997年爱思唯尔科学有限公司
Sub-surface I- maxima (200-600 nM) were found in five of the six profiles from the Somali and Arabian basins of the Northwest Indian Ocean. In addition to these maxima, dissolved I- exhibited normally high (100 nM or greater) values in the surface and values ranging from 3 to 40 nM at depth, which are higher than other open oceanic systems. Sulfide was generally found to be less than 2 nM in the water column, indicating that the chemical reduction of iodate by sulfide is not important in regulating iodine speciation in the Northwest Indian Ocean. These novel high iodide values below the euphotic zone do not appear to be related to other bulk chemical or hydrographic features (sigma(theta)) but may be the result of two distinct biologically mediated remineralization processes: (1) the direct reduction of IO3- to I- as seen in the sub-surface maxima, and (2) release of I- from C-I bonds during the decomposition of organic matter. Iodine normalized to salinity, specific iodine, is not found to be conservative in this system. Overall, our specific iodine data support the incorporation of iodine into organic material in the surface. Iodide, when present below the euphotic zone, is a product of the decomposition of that exported organic material. These data and processes are consistent with those found previously in the Black Sea and the Chesapeake Bay. However, in the Northwest Arabian Sea, iodide and oxygen are measurable throughout the water column, indicating that the system is not at equilibrium with the prevailing redox condition and that traditional thermodynamic considerations of pE do not appear to be applicable. Porewater iodide in the top 150 cm increased with depth to approximately 19 mu M as a result of the release of I- during decomposition of organic matter. (C) 1997 Elsevier Science Ltd.