60 years record of biogenic sulfur from Lambert Glacier basin firn core, East Antarctica

Abstract

AbstractA 15.2 m deep firn core and a 2.7 m snow pit were drilled in the western side of Lambert Glacier basin, East Antarctica, in January 1993. the sampling site LGB16 (72.8˚ S, 57.3˚ E) is located about 650 km from the coast, at approximately 2690ma.s.l. the concentration of methanesulfonate (MSA) was determined in the firn core and snow pit. the continuous MSA record from LGB16, spanning about 60 years from 1933 to 1992, displays a decreasing trend in general, and sharp differences between the upper 10.2 m (corresponding to AD 1952) and the bottom part from 10.2 to 15.2 m. the mean MSA concentration for the whole core is 11.3±14.5 ng g–1; for the upper 10.2 m it is 9.3 ±6.3 ng g–1, compared to 15.4±23.0 ng g–1 for the bottom part. the bottom part has a greater number of high MSA peaks, which is consistent with the Cl– and, to a lesser extent, Na+ records for this core. A negative correlation was observed between sea-ice area for the South Indian Ocean sector (40–90˚E) and MSA concentration in LGB16. No significant link was observed between the high MSA concentration and El Niño events at this location.