The Distribution of Dissolved and Particulate Mo and V along the U.S. GEOTRACES East Pacific Zonal Transect (GP16): The Roles of Oxides and Biogenic Particles In Their Distributions In the Oxygen Deficient Zone and the Hydrothermal Plume
The Distribution of Dissolved and Particulate Mo and V along the U.S. GEOTRACES East Pacific Zonal Transect (GP16): The Roles of Oxides and Biogenic Particles In Their Distributions In the Oxygen Deficient Zone and the Hydrothermal Plume
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DOI：
10.1016/j.marchem.2017.12.003
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发表时间：
2017-12
期刊：
影响因子：
3
通讯作者：
Peng Ho;Jong‐Mi Lee;M. Heller;P. Lam;A. Shiller
中科院分区：
文献类型：
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作者：
Peng Ho;Jong‐Mi Lee;M. Heller;P. Lam;A. Shiller
钼（Mo）和钒（V）是海洋中研究不足的元素，因为它们在很大程度上是保守的。因此，没有详细的海洋部分，这些元素存在，虽然以前的报告确实表明可能的异常，由于生物，氧化还原或吸附过程中，他们的分布。在这里，我们提出了溶解和颗粒Mo和V的第一个详细的海洋部分，作为2013年美国GP 16 GEOTRACES东太平洋带状样带（EPZT）的一部分，从秘鲁到塔希提岛。与以前的工作类似，溶解钼的分布在很大程度上是保守的，而溶解钒显示约5%的消耗在上层沃茨。对于溶解的钼，少数样品表现出显着耗尽的浓度，在大多数情况下，随着时间的推移逐渐增加后，样品被酸化。这意味着原始样品中溶解的钼的形态发生了部分变化，从主要的钼到另一种未知的形式。在缺氧区（ODZ）关闭的秘鲁的保证金，耗尽溶解钼和V在几个样品中对应的亚硝酸盐的最大值，这表明这两个元素在氮循环的可能参与。颗粒Mo和V富集的ODZ可能指示清除铁羟基氧化物和/或生物颗粒。在近地表沃茨靠近秘鲁的边缘，溶解钼和V的浓度略有下降，增加总叶绿素，这表明去除这两个元素的生物吸收和/或吸附到生物颗粒。与以前的报告，减少沿海/河口沉积物的去除导致溶解V的地表水耗尽，有没有证据表明，从EPZT部分，这一过程中发挥了强大的作用，在海洋表面的~ 5%溶解V耗尽的发展。此外，溶解的V和Mo的耗尽被认为是在一些热液羽沃茨以上的山脊，可能是由于吸附到铁/锰氧化物，并建议这些羽沃茨是这两个元素的净汇。脊脊峰颗粒Mo和V与颗粒Mn和Fe载体相的关联表明V主要由Fe羟基氧化物清除，而Mo可能由Fe羟基氧化物和Mn氧化物清除。远离脊顶，溶解的V和Mo的耗尽被认为是沿着远场热液羽的边界，尽管其原因仍然不清楚。未来对这些元素的研究可能会受益于物种形成的确定以及对边缘区域的更多关注。
Molybdenum (Mo) and (V) vanadium are under-studied elements in the ocean due to their largely conservative natures. Thus, no detailed ocean sections of these elements exist although previous reports do suggest possible anomalies in their distributions due to biological, redox, or sorptive processes. Here we present the first detailed ocean sections of dissolved and particulate Mo and V, obtained as part of the 2013 U.S. GP16 GEOTRACES East Pacific Zonal Transect (EPZT) from Peru to Tahiti. Similar to previous work, the distribution of dissolved Mo was largely conservative, while dissolved V showed a ~ 5% depletion in the upper waters. For dissolved Mo, a small number of samples showed significantly depleted concentrations which, in most cases, gradually increased with time after samples were acidified. This implies the original sample had experienced a partial change in speciation of dissolved Mo from the predominant molybdate to another, as yet, unknown form. In the oxygen deficient zone (ODZ) off the Peru margin, depleted dissolved Mo and V in a few samples corresponded with the nitrite maximum, suggesting the possible involvement of both elements in the nitrogen cycle. Particulate Mo and V enrichments in the ODZ are likely indicative of scavenging by Fe oxyhydroxides and/or biogenic particles. In near surface waters close to the Peru margin, dissolved Mo and V concentrations slightly decreased with increasing total chlorophylla, suggesting the removal of both elements by biological uptake and/or adsorption onto biogenic particles. In contrast to previous reports that removal to reducing coastal/estuarine sediments resulted in surface water depletion of dissolved V, there is no evidence from the EPZT section that this process plays a strong role in the development of the ~ 5% dissolved V depletion in the surface ocean. Additionally, dissolved V and Mo depletions were seen in some hydrothermal plume waters above the ridge crest, likely due to adsorption onto Fe/Mn oxides and suggesting that these plume waters are a net sink for these two elements. Associations of ridge crest particulate Mo and V with the particulate Mn and Fe carrier phases suggests V was largely scavenged by Fe oxyhydroxides while Mo was likely scavenged by both Fe oxyhydroxides and Mn oxides. Away from the ridge crest, depletions of dissolved V and Mo are seen along the boundaries of the far field hydrothermal plume, though the reasons for this remain obscure. Future studies of these elements could benefit from determination of speciation as well as increased focus on margin areas.