Aerosol iron speciation and seasonal variation of iron oxidation state over the western Antarctic Peninsula.
Aerosol iron speciation and seasonal variation of iron oxidation state over the western Antarctic Peninsula.
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南极半岛西部气溶胶铁形态和铁氧化态的季节变化。
DOI：
10.1016/j.scitotenv.2022.153890
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Yu Shun
中科院分区：
文献类型：
--
作者：
S. Fan;Yuan Gao;B. Lai;E. Elzinga;Yu Shun
铁（Fe）形态和氧化态被认为是影响铁在大气中溶解度和表层海洋生物利用度的关键因素。在这项研究中，使用基于同步加速器的 X 射线荧光 (XRF) 和 X 射线吸收近边缘结构 (XANES) 光谱测定了在南极西部半岛帕尔默站收集的气溶胶样品中的元素组成和铁形态。粗模式（>1μm）含铁颗粒的元素组成表明，该地区的地壳排放是气溶胶铁的主要来源。这些气溶胶颗粒中的铁矿物主要是赤铁矿和黑云母，但也观察到少量的黄铁矿和钛铁矿。 Fe氧化态表现出明显的季节变化。南半球夏季Fe(II)含量占总铁量的71%，而到南半球冬季则下降至60%。涉及气象参数的多元线性模型表明，风速、相对湿度和太阳辐照度是显着控制南半球夏季Fe(II)百分比的因素。相反，这些因素与南方冬季Fe(II)百分比之间没有发现任何关系，这表明大气光还原和区域沙尘排放是有限的。此外，积雪深度与气溶胶Fe浓度显着相关（p<0.05），证实了雪/冰覆盖对区域粉尘排放的限制作用。鉴于近几十年来南极半岛经历了快速变暖，南极半岛的无冰区可能成为潜在的沙尘源。
The iron (Fe) speciation and oxidation state have been considered critical factors affecting Fe solubility in the atmosphere and bioavailability in the surface ocean. In this study, elemental composition and Fe speciation in aerosol samples collected at the Palmer Station in the West Antarctic Peninsula were determined using synchrotron-based X-ray fluorescence (XRF) and X-ray Absorption Near-Edge Structure (XANES) spectroscopy. The elemental composition of coarse-mode (>1 μm) Fe-containing particles suggests that the region's crustal emission is the primary source of aerosol Fe. The Fe minerals in these aerosol particles were predominantly hematite and biotite, but minor fractions of pyrite and ilmenite were observed as well. The Fe oxidation state showed an evident seasonal variation. The Fe(II) content accounted for 71% of the total Fe in the austral summer, while this fraction dropped to 60% in the austral winter. Multivariate linear models involving meteorological parameters suggested that the wind speed, relative humidity, and solar irradiance were the factors that significantly controlled the percentage of Fe(II) in the austral summer. On the contrary, no relationship was found between these factors and the Fe(II) percentage in the austral winter, suggesting that atmospheric photoreduction and regional dust emission were limited. Moreover, the snow depth was significantly (p < 0.05) correlated with the aerosol Fe concentration, confirming the limiting effect of snow/ice cover on the regional dust emission. Given that the Antarctic Peninsula has experienced rapid warming during recent decades, the ice-free areas in the Antarctic Peninsula may act as potential dust sources.