Total and methyl- mercury analysis of sea ice, seawater, snow, and brine samples collected during the SIPEX II voyage of the Aurora Australis, 2012

Snow samples were collected from undisturbed sites, upwind from the ship, close to the trace metal site. Samples were collected into acid-washed glass jars (SN0 samples), or into acid-washed buckets lined with sterile Ziploc bags (FSN or UFSN samples). Snow samples were allowed to melt overnight at 4 degrees C, then acidified with 1% v/v HCl.

Snow, brine, seawater samples used for mercury analysis were kept in sterile PETG bottles (250 or 500 mL), or acid-washed Teflon, or acid-washed glass bottles or jars, and preserved with 1% v/v HCl. Snow, brine, and seawater samples kept for culturing work were preserved in falcon tubes in 20% v/v glycerol and stored at -80 degrees C. For a detailed record of samples taken and analysed, please refer to the sample inventory spreadsheet.

For mercury analysis, ice core sections were cut in half with a stainless steel trace metal hand saw and melted overnight at ambient temperature in acid-washed 500 mL glass jars. Half of the ice core sections were kept preserved at -20 degrees C for future analytical work. The melt (125-250 mL) was then transferred to acid-washed Teflon bottles and acidified with 1% v/v HCl and kept at ambient temperature.

Total and methylmercury analysis: Seawater, sea ice, snow, and brine samples were analysed for total and methyl- mercury at the Mercury Lab at the USGS Wisconsin Water Research Center in Middleton, Wisconsin in March 2013. Total mercury (HgT) analysis was performed using the Manual HgT procedure outlined on the USGS Mercury Lab's website (wi.water.usgs.gov/mercury-lab/analysis-methods.html), which is based on EPA Method 1631.

Methylmercury (MeHG) analysis was performed per the Brooks-Rand "MERX" by ICPMS isotope dilution method (USGS Open-File Report 01-445, wi.water.usgs.gov/mercury-lab/analysis-methods.html). Data files: Raw data for total mercury are saved as excel spreadsheets (YYYYMMDD_Analyst_HgT.xls), and the original logs of the chromatograms from the PeakNet software (MMDDYY.LOG). Raw data for methylmercury analysis are saved as excel files (YYYYMMDDAnalyst_MeHg Waters.xlsx), and the Chromera reports from the ICPMS.