Distribution of dissolved and particulate metals in Antarctic sea ice

• Published in: Marine Chemistry
• Main Authors: Lannuzel, D, Bowie, AR, Van Der Merwe, P, Townsend, AT, Schoemann, V
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier Science Bv 2011
• Subjects: Earth Sciences; Oceanography; Chemical Oceanography; Antarctic; Austral; Antarc*; Sea ice
• Online Access: https://doi.org/10.1016/j.marchem.2011.01.004; http://ecite.utas.edu.au/76022

Samples were collected in East Antarctic sea ice in late winter/early austral spring 2007 to assess thedistributions of Al, Cr, Mn, Cu, Zn, Mo, Cd and Ba. Total dissolved (b0.2 m) and particulate (N0.2 m)concentrations were measured by Inductively Coupled Plasma-Sector Field Mass Spectrometry (ICP-SFMS) insnow, pack ice and fast ice. Particulate concentrations were also determined in underlying seawater for theseelements. The concentrations of particulate metals were one to two orders of magnitude higher in sea ice thanin snow and seawater, except for Mo and Cr. Barite maxima in sea ice vertical profiles at all sites may indicateheterotrophic activity. Particulate Al and Mn distributions suggest a signal from Antarctica's shelf sediments.Dissolved metals were one order of magnitude higher in sea ice as compared to snow, although they were notenriched in sea ice as compared to data reported in the literature for Antarctic surface waters. An analysis ofdissolved-to-total metal ratios showed that all studied metals were found almost exclusively in the dissolvedphase in Antarctic pack ice. Dissolved metals distributions indicate that spatial variability does not seem to bestrong. Our results also demonstrate that dissolved Al, Cr, Mo and Ba behaved conservatively with bulk icesalinity gradients. This would confirm the main source of trace metals to Antarctic sea ice comes fromseawater and not from direct atmospheric deposition. Dissolved bioactive metals Mn, Cu, Zn and Cdconcentrations were scattered when plotted against bulk ice salinity, but did not show a seasonal decrease norreach limitation status. Finally, seasonal ice melt does not seem to contribute significantly to the supply ofdissolved bioactive metals, other than Fe, to Antarctic surface waters.