TY - JOUR
T1 - Aerosol iron speciation and seasonal variation of iron oxidation state over the western Antarctic Peninsula
AU - Fan, Songyun
AU - Gao, Yuan
AU - Lai, Barry
AU - Elzinga, Evert J.
AU - Yu, Shun
N1 - Funding Information:
This research was sponsored by the US National Science Foundation Grant OPP-1341494 and OCE-2048858 to YG. Sample analyses were performed on Beamline 2-ID-D at the Advanced Photon Source, a US Department of Energy Office of Science User Facility operated by Argonne National Laboratory, under Contract No. DE-AC02-06CH11357. We are grateful to Pami Mukherjee, Rafael Jusino-Atresino, and Guojie Xu for assistance with air sampling preparation. This work would not have become possible without the support from the staff of Palmer Station and the US Antarctic Program.
Publisher Copyright:
© 2022 Elsevier B.V.
PY - 2022/6/10
Y1 - 2022/6/10
N2 - 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.
AB - 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.
KW - Aerosols
KW - Antarctic Peninsula
KW - Fe mineralogy
KW - Fe oxidation states
KW - XANES
UR - http://www.scopus.com/inward/record.url?scp=85124871696&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85124871696&partnerID=8YFLogxK
U2 - 10.1016/j.scitotenv.2022.153890
DO - 10.1016/j.scitotenv.2022.153890
M3 - Article
C2 - 35182624
AN - SCOPUS:85124871696
SN - 0048-9697
VL - 824
JO - Science of the Total Environment
JF - Science of the Total Environment
M1 - 153890
ER -