Meridional Survey of the Central Pacific Reveals Iodide Accumulation in Equatorial Surface Waters and Benthic Sources in the Abyssal Plain
Meridional Survey of the Central Pacific Reveals Iodide Accumulation in Equatorial Surface Waters and Benthic Sources in the Abyssal Plain
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DOI：
10.1029/2021gb007300
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发表时间：
2023-02
影响因子：
5.2
通讯作者：
R. Moriyasu;K. Bolster;D. Hardisty;D. Kadko;M. Stephens;James W. Moffett
中科院分区：
文献类型：
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作者：
R. Moriyasu;K. Bolster;D. Hardisty;D. Kadko;M. Stephens;James W. Moffett
沿着152°W的GEOTRACES GP 15样带，从阿拉斯加陆架到塔希提岛帕皮提，测量了碘酸盐和碘化物的分布。该样带包括阿拉斯加大陆架附近的含氧沃茨，在北太平洋盆地的中央盆地的完整水柱，上层水柱跨越季节性混合制度在北方，贫营养制度在中央环流和赤道上涌。碘化物浓度在永久分层的热带混合层中最高，这反映了由于依赖于光的生物过程而导致的积累，并在真光层以下迅速下降。垂直混合系数（KZ），来自补充7 Be数据，使碘氧化率估计在两个站。3-4年的碘化物半衰期表明季节性混合过程在解释样带南北差异方面的重要性，也有助于混合层以下碘化物浓度随深度的降低。这些估计半衰期与最近的全球碘模型一致。没有证据表明阿拉斯加大陆边缘有大量碘输入，但在盆地内部覆盖深海沉积物的底层沃茨中碘显著富集。
The distributions of iodate and iodide were measured along the GEOTRACES GP15 meridional transect at 152°W from the shelf of Alaska to Papeete, Tahiti. The transect included oxygenated waters near the shelf of Alaska, the full water column in the central basin in the North Pacific Basin, the upper water column spanning across seasonally mixed regimes in the north, oligotrophic regimes in the central gyre, and the equatorial upwelling. Iodide concentrations are highest in the permanently stratified tropical mixed layers, which reflect accumulation due to light‐dependent biological processes, and decline rapidly below the euphotic zone. Vertical mixing coefficients (Kz), derived from complementary 7Be data, enabled iodide oxidation rates to be estimated at two stations. Iodide half‐lives of 3–4 years show the importance of seasonal mixing processes in explaining north‐south differences in the transect, and also contribute to the decrease in iodide concentrations with depth below the mixed layer. These estimated half‐lives are consistent with a recent global iodine model. No evidence was found for significant inputs of iodine from the Alaskan continental margin, but there is a significant enrichment of iodide in bottom waters overlying deep sea sediments from the interior of the basin.