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This data set is a continuous, high-resolution record of biogenic sulfur (methanesulfonate, known as MSA and CH3SO3-) in the 1000 m deep Siple Dome A (SDMA) core, covering the last 100,000 years. Analysis of the core was done between August 2002 and November 2003 at the University of California, Irvine. Investigators used a mass spectrometer to measure methanesulfonate. Measurements are given as MSA concentration at various depths. Estimated age of the ice at each depth is also given.
This project was a part of the West Antarctic Ice Sheet Cores (WAISCORES) project for deep ice coring in West Antarctica. WAISCORES is supported by the Office of Polar Programs, National Science Foundation (NSF).
Saltzman, E., I. Dioumaeva, and B. Finley. 2004. Biogenic Sulfur in the Siple Dome Ice Core. Boulder, CO: National Snow and Ice Data Center. http://dx.doi.org/10.7265/N5S180F1.
|Data format||ASCII text or a Microsoft Excel spreadsheet.|
|Spatial coverage||81.7°S, 148.8°W|
|Temporal coverage and resolution||Temporal coverage is 100,000 to 20 years BP.
Resolution is biannual for uppermost core, 7-8 yrs at 600 m, 50-200 yrs at the core bottom.
|File size||200 KB|
|Parameter(s)||MSA concentration in ppb|
|Procedures for obtaining data||Data are available via FTP.|
University of California, Irvine
Irvine, California, USA
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Biogenic sulfur is a major aerosol-forming constituent of the atmosphere and has potentially important links to the earth's radiation budget. End products of biogenic sulfur transformation are accumulated in ice cores in the form of 1) non-sea-salt sulfate and 2) methanesulfonate (MSA). Previous work on the Vostok ice core has demonstrated a remarkable climate-related variability in biogenic sulfur, suggesting that the sulfur cycle may act to stabilize climate (i.e. keep the glacial atmosphere cool and the interglacial atmosphere warm) in the Southern Hemisphere.
In this study MSA was measured in the Siple Dome ice core in West Antarctica. Siple Dome core is a well-dated, high-resolution, 1000 m deep ice core covering the last 100,000 years. Because the Siple Dome location is in a region strongly impacted by the incursion of marine air, the biogenic sulfur record is expected to be dominated by high-latitude marine sulfur emissions.
This study also demonstrated the utility of electrospray mass spectrometry (ES/MS/MS) for the analysis of aqueous samples from polar ice cores. This new technique allowed University of California, Irvine team of researchers to complete the analysis of more than 4600 samples in duplicates in less than a year. Analytical precision is improved compared to the conventional ion chromatography technique.
Samples from 0-212 m were cut at NICL by UCI personnel and melted at UCI. Most of them were cut at the same depth intervals as those in University of Maine major ion record. Samples below 212 m were aliquots of the samples analyzed by P. Mayewski and co-workers for major ions. They were cut and melted at the University of Maine. The age/depth relationship used to estimate sample ages was provided by the WAISCORES project and should be viewed as preliminary. The data set is presented in eight columns:
File is provided in ASCII text format and in Microsoft Excel format.
The data file size is 200 KB.
Average depth resolution is 0.2 m.
100,000 years BP to 20 years BP.
Biannual for uppermost core, 7-8 yrs at 600 m, 50-200 yrs at the core bottom.
The parameter measured is methanesulfonate (MSA, CH3SO3-).
Unit of measurement is parts per billion (ppb).
Measured MSA concentrations vary from 2.4 ppb to 73.2 ppb.
|Sample #||Top Depth||Bottom Depth||Sample length, m||Depth by midpoint, m||Age by midpoint depth, yrs BP||MSA concentration., ppb||% Relative Standard Deviation (as STDEV/MEAN)|
The mean relative standard deviation on duplicate analysis was 1.5+/-0.3%. The uncertainty associated with calibration was estimated at 0.9+/-0.3%, the mean of the standard errors of the calibration curve slopes. The overall uncertainty associated with the measurements is estimated at 2.4+/-0.6%. All standard deviations are given with 95% confidence interval.
Data are available via FTP.
Please see the Antarctic Glaciological Data Center (AGDC) for related data.
The investigators analyzed methanesulfonate using negative ion electrospray/triple quadrupole mass spectrometry. The instrument used was a ThermoFinnigan TSQ® Quantum mass spectrometer. The samples were diluted 50:50 with methanol and spiked with deuterated MSA (CD3SO3-) as an internal standard for calibration. In total, 4690 samples were analyzed in duplicate, with mean relative standard deviation on duplicate runs as low as 1.5+/-0.3%.
Nereson, N.A., C.F. Raymond, R.W. Jacobel, and E.D. Waddington. 2000. The accumulation pattern across Siple Dome, West Antarctica, inferred from radar-detected internal layers. Journal of Glaciology. 46(152), 75-87.
Kreutz, K.J., Mayewski, P.A., Meeker, L.D., Twickler, M.S., and Whitlow, S.I. 1998. Continuous glaciochemical measurements on the Siple Dome deep ice core. Antarctic Journal of the U.S. 33(5).
Gow, A.J. and H. Engelhardt. 2000. Preliminary analysis of ice cores from Siple Dome, West Antarctica. Physics of Ice Core Records, Hokkaido University Press, Sapporo, Japan.
The following acronyms and abbreviations are used in this document.
|AGDC||Antarctic Glaciological Data Center|
|FTP||File Transfer Protocol|
|NSF||National Science Foundation|
|ppb||parts per billion|
|SDMA||Siple Dome A|
|WAIS||West Antarctic Ice Sheet|