Spatial variability of aerosol iron mineralogy and oxidation states over the Arctic Ocean
Spatial variability of aerosol iron mineralogy and oxidation states over the Arctic Ocean
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北冰洋气溶胶铁矿物学和氧化态的空间变化
DOI：
10.1016/j.scitotenv.2023.164301
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发表时间：
2023
影响因子：
9.8
通讯作者：
Gao, Yuan
中科院分区：
文献类型：
--
作者：
Fan, Songyun;Lai, Barry;Elzinga, Evert J.;Ingall, Ellery D.;Morton, Peter L.;Gao, Yuan
气溶胶铁的矿物学和氧化态对控制气溶胶铁在海水中的溶解度和生物有效性起着重要作用。在这项研究中，在美国GEOTRACES西北极巡航（GN 01）收集的气溶胶中的铁矿物和氧化态的空间变异性进行了测定，使用基于同步加速器的X射线吸收近边结构（XANES）光谱。在这些样品中发现了Fe（II）矿物（黑云母、钛铁矿）和Fe（III）矿物（水铁矿、赤铁矿、Fe（III）磷酸盐）。然而，在这次巡航中观察到的气溶胶Fe矿物学和溶解度在空间上是不同的，并且可以根据影响不同区域收集的气溶胶的气团分为三个集群：（1）富含黑云母的颗粒（87%黑云母，13%赤铁矿）与经过阿拉斯加上空的空气质量，显示出相对较低的铁溶解度（4.0 ± 1.7%）;（2）富铁尖晶石颗粒在偏远的北极空气中收集的（82%水铁矿，18%钛铁矿），显示出相对较高的Fe溶解度（9.6 ± 3.3%）;（3）来自北美和西伯利亚的新鲜尘，主要以赤铁矿为主（41%赤铁矿，25%磷酸铁（III），20%黑云母，13%水铁矿），显示出相对低的Fe溶解度（5.1 ± 3.5）。一个显着的正相关关系，发现铁的氧化态和铁的分数溶解度，这表明，远程传输可以修改铁（氢）氧化物，如水铁矿通过大气处理，影响气溶胶铁的溶解度，从而铁的生物利用度在遥远的北冰洋。
The mineralogy and oxidation state of aerosol iron (Fe) play important roles in controlling aerosol Fe solubility and consequent bioavailability in seawater. In this study, the spatial variability of Fe mineralogy and oxidation states in aerosols collected during the US GEOTRACES Western Arctic cruise (GN01) were determined using synchrotron-based X-ray absorption near edge structure (XANES) spectroscopy. Both Fe(II) minerals (biotite, ilmenite) and Fe(III) minerals (ferrihydrite, hematite, Fe(III) phosphate) were found in these samples. However, aerosol Fe mineralogy and solubility observed during this cruise varied spatially and can be grouped into three clusters based on the air masses that affected aerosols collected in different regions: (1) biotite-enriched particles (87 % biotite, 13 % hematite) with the air masses passing over Alaska, showing relatively low Fe solubility (4.0 ± 1.7 %); (2) ferrihydrite-enriched particles (82 % ferrihydrite, 18 % ilmenite) collected in the remote Arctic air, showing relatively high Fe solubility (9.6 ± 3.3 %); (3) the fresh dust derived from North America and Siberia, primarily dominated by hematite (41 % hematite, 25 % Fe(III) phosphate, 20 % biotite, 13 % ferrihydrite), showing relatively low Fe solubility (5.1 ± 3.5). A significant positive correlation was found between Fe oxidation state and Fe fractional solubility, suggesting that long-range transport could modify iron (hydr) oxide such as ferrihydrite through atmospheric processing, influencing aerosol Fe solubility and consequently Fe bioavailability in the remote Arctic Ocean.