Trace element, rare earth element and trace carbon compounds in Subglacial Lake Whillans, West Antarctica

Clara Turetta; Elena Barbaro; Mark L Skidmore; Andrea Gambaro; Alexander B Michaud; Andrew C Mitchell; Trista J Vick-Majors; John C Priscu; Carlo Barbante

doi:10.1016/j.scitotenv.2023.164480

Trace element, rare earth element and trace carbon compounds in Subglacial Lake Whillans, West Antarctica

Sci Total Environ. 2023 Sep 20:892:164480. doi: 10.1016/j.scitotenv.2023.164480. Epub 2023 May 30.

Authors

Clara Turetta¹, Elena Barbaro², Mark L Skidmore³, Andrea Gambaro¹, Alexander B Michaud⁴, Andrew C Mitchell⁵, Trista J Vick-Majors⁶, John C Priscu⁷, Carlo Barbante¹

Affiliations

¹ Institute of Polar Sciences CNR, Via Torino 155, 30172 Mestre-Venezia, Italy; Department of Environmental Sciences, Informatics and Statistics, University of Venice, Ca' Foscari, Via Torino 155, 30172 Mestre-Venezia, Italy.
² Institute of Polar Sciences CNR, Via Torino 155, 30172 Mestre-Venezia, Italy; Department of Environmental Sciences, Informatics and Statistics, University of Venice, Ca' Foscari, Via Torino 155, 30172 Mestre-Venezia, Italy. Electronic address: elena.barbaro@cnr.it.
³ Department of Earth Sciences, Montana State University, Bozeman, MT 59717, USA.
⁴ Bigelow Laboratory for Ocean Sciences, East Boothbay, ME 04544, USA.
⁵ Department of Geography and Earth Sciences, Aberystwyth University, Aberystwyth, Wales, UK.
⁶ Department of Biological Sciences and Great Lakes Research Center, Michigan Technological University, Houghton, MI, USA.
⁷ Polar Oceans Research Group, Sheridan, MT 59749, USA.

PMID: 37263426
DOI: 10.1016/j.scitotenv.2023.164480

Abstract

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.

Keywords: Amino acids; Lake water; Phenolic compounds; Porewater; REE; Redox conditions; SLW; TE; West Antarctica.

MeSH terms

Antarctic Regions
Carbon
Lakes / chemistry
Metals, Rare Earth* / analysis
Trace Elements* / analysis

Substances

Trace Elements
Metals, Rare Earth
Carbon