Methanesulfonate in the Greenland Ice Sheet Project 2 Ice Core

In this paper we present measurements of methanesulfonate in the Greenland Ice Sheet Project 2 (GISP2) ice core. Methanesulfonate is an atmospheric oxidation product of dimethylsulfide. The GISP2 methanesulfonate record contains information about the atmospheric loading of biogenic sulfur over the past 110 kyr and its relationship to climate change. The GISP2 data set supports the inferences made from the Renland ice core from Greenland that the glacial atmosphere over Greenland had reduced concentrations of biogenic sulfur compared with the present day [Hansson and Saltzman, 1993]. We conclude that the flux of biogenic sulfur from the North Atlantic Ocean must have been lower during glacial times and speculate that this decrease may have been related to differences in phytoplankton speciation. The data suggest that changes in direct radiative forcing from biogenic sulfur aerosols would act as negative feedback to the glacial/interglacial climate cycles in this region

Two-hundred-year Record of Biogenic Sulfur in a South Greenland Ice Core (20D)

The concentration of methanesulfonic acid (MSA) was determined in a shallow south central Greenland ice core(20D). This study provides a high-resolution record of the DMS-derived biogenic sulfur in Greenland precipitation over the past 200 years. The mean concentration of MSA is 3.30 ppb(σ = 2.38 ppb,n = 1134). The general trend of MSA is an increase from 3.01 to 4.10 ppb between 1767 and 1900, followed by a steady decrease to 2.34 ppb at the present time. This trend is in marked contrast to that of non-sea-salt sulfate (nss SO42-), which increases dramatically after 1900 due to the input of anthropogenic sulfur. The MSA fraction ((MSA/(MSA+ nss SO42-))* 100) ranges from a mean of 15% in preindustrial ice to less than 5% in recent ice. These MSA fraction suggest that approximately 5 to 40% of the sulfur in recent Greenland ice is of biological origin. It is suggested that there is a significant low-latitude component to the biogenic sulfur in the core and that variations in the MSA fraction reflect changes in the relative strengths of low- and high-latitude inputs. The data shown o evidence for a strong dependence of dimethyl sulfide(DMS) emissions on sea surface temperature during the last century. There is also no indication that the yield of MSA from DMS oxidation has been altered by increased NOx levels over the North Atlantic during this period

An Ice-Core-Based, Late Holocene History for the Transantarctic Mountains, Antarctica

Ice core records (major anions and cations, MSA, oxygen isotopes and particles) developed from two shallow (~200 m depth) sites in the Transantarctic Mountains provide documentation of much of the Holocene paleoenvironmental history of this region. From the more southerly site, Dominion Range, an ~7000-year-long record reveals change in the influence of tropospheric transport to the region. At this site, milder conditions and increased tropospheric inflow prior to ~1500 yr BP are characterized by increased seasalt (ss), terrestrial and marine biogenic inputs. Increased persistence and/or extent of polar stratospheric clouds accompanying generally cooler conditions characterize much of the period since ~1500 yr BP. From the more northerly site, Newall Glacier, the dramatic influence of the retreat of grounded ice from McMurdo Sound dated at[Denton et al., 1989] dominates much of the ice core record. This regional environmental change is documented by massive influxes to the core site of evaporitic salts from areas exposed during low lake level stands. During the past ~150 yr, both Dominion Range and Newall Glacier appear to be experiencing an overall increase in the exposure of ice-free terrain

Two-hundred-year record of biogenic sulfur in a south Greenland ice core (20D)

The concentration of methanesulfonic acid (MSA) was determined in a shallow south central Greenland ice core(20D). This study provides a high-resolution record of the DMS-derived biogenic sulfur in Greenland precipitation over the past 200 years. The mean concentration of MSA is 3.30 ppb(σ = 2.38 ppb,n = 1134). The general trend of MSA is an increase from 3.01 to 4.10 ppb between 1767 and 1900, followed by a steady decrease to 2.34 ppb at the present time. This trend is in marked contrast to that of non-sea-salt sulfate (nss SO42-), which increases dramatically after 1900 due to the input of anthropogenic sulfur. The MSA fraction ((MSA/(MSA+ nss SO42-))* 100) ranges from a mean of 15% in preindustrial ice to less than 5% in recent ice. These MSA fraction suggest that approximately 5 to 40% of the sulfur in recent Greenland ice is of biological origin. It is suggested that there is a significant low-latitude component to the biogenic sulfur in the core and that variations in the MSA fraction reflect changes in the relative strengths of low- and high-latitude inputs. The data shown o evidence for a strong dependence of dimethyl sulfide(DMS) emissions on sea surface temperature during the last century. There is also no indication that the yield of MSA from DMS oxidation has been altered by increased NOx levels over the North Atlantic during this period

Methanesulfonate in the Greenland Ice Sheet Project 2 Ice Core

In this paper we present measurements of methanesulfonate in the Greenland Ice Sheet Project 2 (GISP2) ice core. Methanesulfonate is an atmospheric oxidation product of dimethylsulfide. The GISP2 methanesulfonate record contains information about the atmospheric loading of biogenic sulfur over the past 110 kyr and its relationship to climate change. The GISP2 data set supports the inferences made from the Renland ice core from Greenland that the glacial atmosphere over Greenland had reduced concentrations of biogenic sulfur compared with the present day [Hansson and Saltzman, 1993]. We conclude that the flux of biogenic sulfur from the North Atlantic Ocean must have been lower during glacial times and speculate that this decrease may have been related to differences in phytoplankton speciation. The data suggest that changes in direct radiative forcing from biogenic sulfur aerosols would act as negative feedback to the glacial/interglacial climate cycles in this region

Methanesulfonate in the Greenland Ice Sheet Project 2 Ice Core

In this paper we present measurements of methanesulfonate in the Greenland Ice Sheet Project 2 (GISP2) ice core. Methanesulfonate is an atmospheric oxidation product of dimethylsulfide. The GISP2 methanesulfonate record contains information about the atmospheric loading of biogenic sulfur over the past 110 kyr and its relationship to climate change. The GISP2 data set supports the inferences made from the Renland ice core from Greenland that the glacial atmosphere over Greenland had reduced concentrations of biogenic sulfur compared with the present day [Hansson and Saltzman, 1993]. We conclude that the flux of biogenic sulfur from the North Atlantic Ocean must have been lower during glacial times and speculate that this decrease may have been related to differences in phytoplankton speciation. The data suggest that changes in direct radiative forcing from biogenic sulfur aerosols would act as negative feedback to the glacial/interglacial climate cycles in this region

Performance of the HPLC/fluorescence SO 2 detector during the GASIE instrument intercomparison experiment

Sulfur dioxide (SO2) in synthetic air and diluted ambient air was measured as part of the Gas-Phase Sulfur Intercomparison Experiment (GASIE) using the high performance liquid chromatography (HPLC)/fluorescence technique. SO2 was analyzed by equilibrating the gaseous sample with aqueous SO2, sulfite, and bisulfite, then converting the aqueous S(IV) to an isoindole derivative. The derivative was separated by reversed phase HPLC and detected via fluorescence. The system was calibrated with mixtures of SO2 in zero air prepared from an SO2 permeation device through a two-stage dilution system. The instrument has a 4-min. sample integration time and a measurement period of 9-min. During the GASIE intercomparison the lower limit of detection averaged 3.6 parts per trillion by volume (pptv). The precision of replicate measurements over the entire intercomparison period was better than 5% at the 20 pptv level. Instrument performance was unaffected by the interferent gases included in the GASIE protocol (H2O, O3, NOx, DMS, CO, CO2, and CH4). During diluted ambient air tests, the HPLC/fluorescence technique exhibited an approximately 10% reduction in response relative to some other techniques. The cause of this apparent calibration change is not understood

A 340 year record of biogenic sulphur from the Weddell Sea area, Antarctic

The high MSA (methanesulphonic acid) concentration reflects the proximity of the Weddell Sea, believed to be a region of high marine phytoplankton production. The overall mean nss-SO2-4 (non sea salt sulphate) concentration is about 66% of the total sulphate deposited in snowfall. Low-frequency variations of MSA and ozygen-isotope signals correlate closely, indicating that they may be modulated by similar atmospheric processes. Positive correlations are observed between the oxygen-isotope signature and both MSA and nss SO2-4. A small negative correlation can be seen between both species and the annual duration of sea ice at Scotia Bay, Laurie Island in the South Orkneys, since 1902. -from Author