Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto, 611-0011, Japan.
Sci Rep. 2019 Aug 12;9(1):11652. doi: 10.1038/s41598-019-48035-1.
Recent studies have elucidated that iron (Fe) is a critical trace metal that influences the productivity of marine ecosystems and the biogeochemical cycles of other elements in the modern ocean. However, our understanding of the biogeochemistry of Fe remains incomplete. Herein, we report basin-scale and full-depth sectional distributions of total dissolvable iron (tdFe), dissolved iron (dFe), and labile particulate iron (lpFe = tdFe - dFe) in the North Pacific Ocean, as observed during three cruises of the GEOTRACES Japan program. We found that lpFe dominates tdFe and is significantly correlated with labile particulate aluminum (lpAl): lpFe [nmol kg] = (0.544 ± 0.005) lpAl [nmol kg] + 0.11 ± 0.04, r = 0.968, n = 432. The results indicate a major lithogenic contribution to the distribution of particulate Fe. For dFe, the unique distribution is attributed to the combined effects of biogeochemical cycling, manganese reduction, and lithogenic contribution. Based on concurrent observations of Fe, Al, and manganese (Mn), we infer that the width of the boundary scavenging zone is approximately 500 km off the Aleutian shelf. We estimate the inventory of tdFe in the North Pacific as 1.1 × 10 mol, which is approximately four times that of dFe. Our results emphasize the potential importance of lpFe in the ocean's iron cycle.
最近的研究表明，铁（Fe）是一种关键的痕量金属，它影响海洋生态系统的生产力和现代海洋中其他元素的生物地球化学循环。然而，我们对铁的生物地球化学仍了解不足。在此，我们报告了在日本地球化学追踪计划（GEOTRACES Japan program）的三次考察中，北太平洋总可溶解铁（tdFe）、溶解铁（dFe）和易失性颗粒铁（lpFe=tdFe-dFe）的盆地区域和全水深断面分布。我们发现 lpFe 占 tdFe 的主导地位，且与易失性颗粒铝（lpAl）显著相关：lpFe [nmol kg]=（0.544±0.005）lpAl [nmol kg]+0.11±0.04，r=0.968，n=432。结果表明，颗粒铁的分布主要受生源贡献的影响。对于 dFe，其独特的分布归因于生物地球化学循环、锰还原和生源贡献的综合作用。基于同时观测到的铁、铝和锰（Mn），我们推断边界吸积带的宽度约为阿留申群岛架外 500 公里。我们估计北太平洋的 tdFe 储量为 1.1×10^6 mol，约为 dFe 的四倍。我们的研究结果强调了 lpFe 在海洋铁循环中的潜在重要性。
