Biogenic Sulfur in the Siple Dome Ice Core

Summary

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).

Citing These Data

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.

Overview Table

Category Description
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.

Table of Contents

1. Contacts and Acknowledgments
2. Detailed Data Description
3. Data Access and Tools
4. Data Acquisition and Processing
5. References and Related Publications
6. Document Information

1. Contacts and Acknowledgments

Investigator(s) Name and Title

Eric Saltzman
Irina Dioumaeva
Brandon Finley
University of California, Irvine
Irvine, California, USA

Technical Contact

NSIDC User Services
National Snow and Ice Data Center
CIRES, 449 UCB
University of Colorado
Boulder, CO 80309-0449  USA
phone: +1 303.492.6199
fax: +1 303.492.2468
form: Contact NSIDC User Services
e-mail: nsidc@nsidc.org

2. Detailed Data Description

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:

Format

File is provided in ASCII text format and in Microsoft Excel format.

File Size

The data file size is 200 KB.

Spatial Coverage

81.7°S, 148.8°W

Spatial Resolution

Average depth resolution is 0.2 m.

Temporal Coverage

100,000 years BP to 20 years BP.

Temporal Resolution

Biannual for uppermost core, 7-8 yrs at 600 m, 50-200 yrs at the core bottom.

Parameter or Variable

The parameter measured is methanesulfonate (MSA, CH3SO3-).

Unit of Measurement

Unit of measurement is parts per billion (ppb).

Parameter Range

Measured MSA concentrations vary from 2.4 ppb to 73.2 ppb.

Sample Data Record

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)
1a 4.32 4.54 0.22 4.43 21 6.5 2.1%
1b 4.54 4.83 0.29 4.69 21 9.0 0.9%
2a 4.83 5.12 0.29 4.98 23 11.8 1.0%
2b 5.12 5.46 0.34 5.29 24 9.4 0.1%
2c 5.46 5.62 0.17 5.54 25 22.7 0.5%

Error Sources

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.

3. Data Access and Tools

Data Access

Data are available via FTP.

Related Data Collections

Please see the Antarctic Glaciological Data Center (AGDC) for related data.

4. Data Acquisition and Processing

Theory of Measurements

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%.

5. References and Related Publications

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.

6. Document Information

Acronyms and Abbreviations

The following acronyms and abbreviations are used in this document.

AGDC Antarctic Glaciological Data Center
FTP File Transfer Protocol
MSA methanesulfonate
NSF National Science Foundation
ppb parts per billion
SDMA Siple Dome A
WAIS West Antarctic Ice Sheet

Document Creation Date

February 2004

Document URL

http://nsidc.org/data/docs/agdc/nsidc0201_saltzman/index.html