TY - JOUR
T1 - Trace element, rare earth element and trace carbon compounds in Subglacial Lake Whillans, West Antarctica
AU - Turetta, Clara
AU - Barbaro, Elena
AU - Skidmore, Mark L.
AU - Gambaro, Andrea
AU - Michaud, Alexander B.
AU - Mitchell, Andrew C.
AU - Vick-Majors, Trista J.
AU - Priscu, John C.
AU - Barbante, Carlo
N1 - Funding Information:
Support was provided by the Italian National Antarctic Program ( PNRA - 2009/A2.02 , CaBILA project). The authors thank the WISSARD science team for assistance in project planning and sample collection. The Whillans Ice Stream Subglacial Access Research Drilling (WISSARD) project was funded by National Science Foundation grants ( OPP-0838933 , 1346250 , 1439774 ). Partial support was provided by graduate fellowships from the NSF-IGERT Program ( 0654336 ), Montana Space Grant Consortium and NSF-Center for Dark Energy Biosphere Investigations (A.B.M) and a dissertation grant from the American Association of University Women (T.J.V-M). The authors thank Elga Lab water, High Wycombe UK for supplying the pure water systems used in this study.
Publisher Copyright:
© 2023 Elsevier B.V.
PY - 2023/9/20
Y1 - 2023/9/20
N2 - Whillans Subglacial Lake (SLW) lies beneath 801 m of ice in the lower portion of the Whillans Ice Stream (WIS) in West Antarctica and is part of an extensive and active subglacial drainage network. Here, the geochemical characterization of SLW rare earth elements (REE), trace elements (TE), free amino acids (FAA), and phenolic compounds (PC) measured in lakewater and sediment porewater are reported. The results show, on average, higher values of REEs in the lakewater than in the porewater, and clear changes in all REE concentrations and select redox sensitive trace element concentrations in porewaters at a depth of ~15 cm in the 38 cm lake sediment core. This is consistent with prior results on the lake sediment redox conditions based on gas chemistry and microbiological data. Low concentrations of vanillyl phenols were measured in the SLW water column with higher concentrations in porewater samples and their concentration profiles in the sediments may also reflect changing redox conditions in the sediments. Vanillin concentrations increased with depth in the sediments as oxygenation decreases, while the concentrations of vanillic acid, the more oxidized component, were higher in the more oxygenated surface sediments. Collectively these results indicate redox changes occurring with the upper 38 cm of sediment in SLW and provide support for the existence of a seawater source, already hypothesized, in the sediments below the lowest measured depth, and of a complex and dynamic geochemical system beneath the West Antarctic Ice Sheet. Our results are the first to detail geochemical properties from an Antarctic subglacial environment using direct sampling technology. Due to their isolation from the wider environment, subglacial lakes represent one of our planets last pristine environments that provide habitats for microbial life and natural biogeochemical cycles but also impact the basal hydrology and can cause ice flow variations.
AB - Whillans Subglacial Lake (SLW) lies beneath 801 m of ice in the lower portion of the Whillans Ice Stream (WIS) in West Antarctica and is part of an extensive and active subglacial drainage network. Here, the geochemical characterization of SLW rare earth elements (REE), trace elements (TE), free amino acids (FAA), and phenolic compounds (PC) measured in lakewater and sediment porewater are reported. The results show, on average, higher values of REEs in the lakewater than in the porewater, and clear changes in all REE concentrations and select redox sensitive trace element concentrations in porewaters at a depth of ~15 cm in the 38 cm lake sediment core. This is consistent with prior results on the lake sediment redox conditions based on gas chemistry and microbiological data. Low concentrations of vanillyl phenols were measured in the SLW water column with higher concentrations in porewater samples and their concentration profiles in the sediments may also reflect changing redox conditions in the sediments. Vanillin concentrations increased with depth in the sediments as oxygenation decreases, while the concentrations of vanillic acid, the more oxidized component, were higher in the more oxygenated surface sediments. Collectively these results indicate redox changes occurring with the upper 38 cm of sediment in SLW and provide support for the existence of a seawater source, already hypothesized, in the sediments below the lowest measured depth, and of a complex and dynamic geochemical system beneath the West Antarctic Ice Sheet. Our results are the first to detail geochemical properties from an Antarctic subglacial environment using direct sampling technology. Due to their isolation from the wider environment, subglacial lakes represent one of our planets last pristine environments that provide habitats for microbial life and natural biogeochemical cycles but also impact the basal hydrology and can cause ice flow variations.
KW - Amino acids
KW - Lake water
KW - Phenolic compounds
KW - Porewater
KW - Redox conditions
KW - REE
KW - SLW
KW - TE
KW - West Antarctica
KW - Antarctic Regions
KW - Metals, Rare Earth/analysis
KW - Carbon
KW - Trace Elements/analysis
KW - Lakes/chemistry
UR - http://www.scopus.com/inward/record.url?scp=85160684017&partnerID=8YFLogxK
U2 - 10.1016/j.scitotenv.2023.164480
DO - 10.1016/j.scitotenv.2023.164480
M3 - Article
C2 - 37263426
AN - SCOPUS:85160684017
SN - 0048-9697
VL - 892
JO - Science of the Total Environment
JF - Science of the Total Environment
M1 - 164480
ER -