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Kagawa M, Katsuta N, Naito S, Masuki Y, Yoshimizu C, Chiba H, Tayasu I. Sample pretreatment effects on isotopic compositions of oxygen and sulfur in BaSO 4 derived from atmospheric sulfate. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2023; 37:e9659. [PMID: 37953543 DOI: 10.1002/rcm.9659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 09/23/2023] [Accepted: 10/03/2023] [Indexed: 11/14/2023]
Abstract
RATIONALE Preparation of BaSO4 from samples of atmospheric rain, snow, and aerosols has been used for δ18 O and δ34 S analyses. In the present study, we investigated the effect of various sample pretreatments on δ18 O and δ34 S values determined from a Na2 SO4 reagent solution and samples of atmospheric precipitation to improve assay time and cost efficiency. METHODS BaSO4 was prepared from a Na2 SO4 solution by (a) evaporative concentration, (b) evaporation to dryness, (c) evaporation to dryness after adding HCl, and (d) evaporation to concentration after adding HCl, followed by cooling and then precipitation using a BaCl2 solution. To analyze the atmospheric precipitation samples for δ18 O, BaSO4 prepared from the samples was treated with diethylenetriaminepentaacetic acid (DTPA) and SO4 2- and separated chromatographically. The values of δ18 O and δ34 S were measured using a continuous-flow elemental analyzer coupled to an isotope-ratio mass spectrometer. RESULTS The δ34 S values in BaSO4 precipitated from Na2 SO4 solution determined by methods (a)-(c) were consistent within precisions of ±0.5‰. The δ18 O values of methods (a) and (b) were consistent within ±0.2‰, whereas the δ18 O values of methods (c) and (d) increased with increasing HCl concentrations. Similar results were obtained from samples of atmospheric precipitations. The δ18 O values from DTPA-treated BaSO4 were consistent with those obtained by chromatographic separation within ±0.5‰. CONCLUSIONS We found no significant differences in the effects of various pretreatments (acidification, heating, concentration, and drying) on δ18 O and δ34 S values in sulfate from samples of atmospheric precipitation and aerosols extracted as BaSO4 if HCl was not added to the sample before heating and BaSO4 was treated with DTPA for the δ18 O analysis.
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Affiliation(s)
| | | | - Sayuri Naito
- Faculty of Education, Gifu University, Gifu, Japan
| | - Yuma Masuki
- Graduate School of Natural Science and Technology, Gifu University, Gifu, Japan
| | | | - Hitoshi Chiba
- Graduate School of Natural Science and Technology, Okayama University, Okayama, Japan
| | - Ichiro Tayasu
- Research Institute for Humanity and Nature, Kyoto, Japan
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Kim Y, Lee I, Farquhar J, Kang J, Villa IM, Kim H. Multi isotope systematics of precipitation to trace the sources of air pollutants in Seoul, Korea. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 286:117548. [PMID: 34438485 DOI: 10.1016/j.envpol.2021.117548] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 05/27/2021] [Accepted: 06/04/2021] [Indexed: 06/13/2023]
Abstract
Multiple sulfur (δ34Ssulfate, Δ33Ssulfate, & Δ36Ssulfate), nitrogen and oxygen (δ15Nnitrate & δ18Onitrate) and strontium (87Sr/86Sr) isotope compositions of precipitation collected from Seoul, South Korea were analyzed to study the sources, transportation and deposition of air pollutants in East Asia. The δ34Ssulfate values (from 1.9 to 14.6‰ with a median of 4.7‰) and the δ15Nnitrate values (from -2.0 to 13.3‰ with a median of 1.0‰) suggest that fossil fuel use (emission from coal combustion and vehicle exhaust) is a predominant source for sulfur and nitrogen, but other natural sources including biogenic contributions of DMS also add to their total budget. The seasonal variations are observed in δ34Ssulfate and δ15Nnitrate values (both higher in winter season), which is likely to result from the increase of coal use for domestic heating in China. The δ18Onitrate values also varied seasonally depending on the NOx oxidation pathway, being about 20‰ higher in winter than in summer season. The Δ33Ssulfate and Δ36Ssulfate values are not anomalous, showing the absence of MIF signals in precipitation of Seoul. The 87Sr/86Sr ratio of the precipitation samples range from 0.70988 to 0.71487 with a median of 0.71073, indicating the influence of at least three end-member (silicate dust, carbonate dust and anthropogenic emission). Ionic ratios such as (K++NH4+)/(Ca2++Mg2+) and Cl-/Na+ suggest the overwhelming effect of anthropogenic input rather than carbonate dust on the end-member with lower 87Sr/86Sr ratios.
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Affiliation(s)
- Yeongmin Kim
- Research Center for Geochronology and Isotope Analysis, Korea Basic Science Institute, Cheongju, 28119, Republic of Korea
| | - Insung Lee
- School of Earth and Environmental Sciences, Seoul National University, Seoul, 08826, Republic of Korea.
| | - James Farquhar
- Department of Geology, University of Maryland, College Park, MD, 20742, USA
| | - Jisuk Kang
- Institute of Geological Sciences, University of Bern, Baltzerstrasse 3, CH-3012, Bern, Switzerland
| | - Igor M Villa
- Institute of Geological Sciences, University of Bern, Baltzerstrasse 3, CH-3012, Bern, Switzerland; Centro Universitario Datazioni e Archeometria, Università di Milano Bicocca, 20126, Milano, Italy
| | - Hyoungbum Kim
- Department of Earth Science Education, Chungbuk National University, Cheongju, 28644, Republic of Korea
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Wang X, Li J, Sun R, Jiang H, Zong Z, Tian C, Xie L, Li Q, Jia W, Peng P, Zhang G. Regional characteristics of atmospheric δ 34S-SO 42- over three parts of Asia monitored by quartz wool-based passive samplers. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 778:146107. [PMID: 33714091 DOI: 10.1016/j.scitotenv.2021.146107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 02/22/2021] [Accepted: 02/23/2021] [Indexed: 06/12/2023]
Abstract
A new method is presented for measuring atmospheric contents and δ34S-SO42- in airborne particulate matter using quartz wool disk passive air samplers (Pas-QW). The ability of Pas-QW samplers to provide time-integrated measurements of atmospheric SO42- was confirmed in a field calibration study. The average sampling rate of SO42- measured was 2.3 ± 0.3 m3/day, and this was not greatly affected by changes in meteorological parameters. The results of simultaneous sampling campaign showed that the average SO42- contents in Pakistan and the Indochina Peninsula (ICP) were relatively lower than that of China. The spatial distribution of SO42- concentrations was largely attributed to the development of the regional economies. The range of δ34S values observed in Pakistan (4.3 ± 1.4‰) and the ICP (4.5 ± 1.2‰) were relatively small, while a large range of δ34S values was observed in China (3.9 ± 2.5‰). The regional distribution of sulfur isotope compositions was significantly affected by coal combustion. A source analysis based on a Bayesian mixing model showed that 80.4 ± 13.1% and 19.6 ± 13.1% of artificial sulfur dioxide (SO2) sources in China could be attributed to coal combustion and oil combustion, respectively. The two sources differed greatly between regions, and the contribution of oil combustion in cities was higher than previously reported data obtained from emission inventories. This study confirmed that the Pas-QW is a promising tool for simultaneously monitoring atmospheric δ34S-SO42- over large regions, and that the results of the isotope models can provide a reference for the compilation of SO2 emission inventories.
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Affiliation(s)
- Xiao Wang
- State Key Laboratory of Organic Geochemistry and Guangdong province Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; CAS Center for Excellence in Deep Earth Science, Guangzhou 510640, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jun Li
- State Key Laboratory of Organic Geochemistry and Guangdong province Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; CAS Center for Excellence in Deep Earth Science, Guangzhou 510640, China; Guangdong-Hong Kong-Macao Joint Laboratory for Environmental Pollution and Control, Guangzhou Institute of Geochemistry, Chinese Academy of Science, Guangzhou 510640, China.
| | - Rong Sun
- State Key Laboratory of Organic Geochemistry and Guangdong province Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; CAS Center for Excellence in Deep Earth Science, Guangzhou 510640, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hongxing Jiang
- State Key Laboratory of Organic Geochemistry and Guangdong province Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; CAS Center for Excellence in Deep Earth Science, Guangzhou 510640, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zheng Zong
- Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003, China
| | - Chongguo Tian
- Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003, China
| | - Luhua Xie
- Key Laboratory of Ocean and Marginal Sea Geology, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China
| | - Qilu Li
- School of Environment, Henan Normal University, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Xinxiang 453007, China
| | - Wanglu Jia
- State Key Laboratory of Organic Geochemistry and Guangdong province Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China
| | - Ping'an Peng
- State Key Laboratory of Organic Geochemistry and Guangdong province Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; CAS Center for Excellence in Deep Earth Science, Guangzhou 510640, China; Guangdong-Hong Kong-Macao Joint Laboratory for Environmental Pollution and Control, Guangzhou Institute of Geochemistry, Chinese Academy of Science, Guangzhou 510640, China
| | - Gan Zhang
- State Key Laboratory of Organic Geochemistry and Guangdong province Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; CAS Center for Excellence in Deep Earth Science, Guangzhou 510640, China; Guangdong-Hong Kong-Macao Joint Laboratory for Environmental Pollution and Control, Guangzhou Institute of Geochemistry, Chinese Academy of Science, Guangzhou 510640, China
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Reduced marine phytoplankton sulphur emissions in the Southern Ocean during the past seven glacials. Nat Commun 2019; 10:3247. [PMID: 31324761 PMCID: PMC6642193 DOI: 10.1038/s41467-019-11128-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2018] [Accepted: 06/24/2019] [Indexed: 11/29/2022] Open
Abstract
Marine biogenic sulphur affects Earth’s radiation budget and may be an indicator of primary productivity in the Southern Ocean, which is closely related to atmospheric CO2 variability through the biological pump. Previous ice-core studies in Antarctica show little climate dependence of marine biogenic sulphur emissions and hence primary productivity, contradictory to marine sediment records. Here we present new 720,000-year ice core records from Dome Fuji in East Antarctica and show that a large portion of non-sea-salt sulphate, which was traditionally used as a proxy for marine biogenic sulphate, likely originates from terrestrial dust during glacials. By correcting for this, we make a revised calculation of biogenic sulphate and find that its flux is reduced in glacial periods. Our results suggest reduced dimethylsulphide emissions in the Antarctic Zone of the Southern Ocean during glacials and provide new evidence for the coupling between climate and the Southern Ocean sulphur cycle. Ice core derived marine biogenic sulphate does not agree with marine sediment records. Here based on new ice core records spanning the past 720,000 years obtained from Dome Fuji the authors propose that dust contributed a higher percentage of sulphate aerosols than previously thought.
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Han X, Guo Q, Strauss H, Liu C, Hu J, Guo Z, Wei R, Peters M, Tian L, Kong J. Multiple Sulfur Isotope Constraints on Sources and Formation Processes of Sulfate in Beijing PM 2.5 Aerosol. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:7794-7803. [PMID: 28605583 DOI: 10.1021/acs.est.7b00280] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Recently air pollution is seriously threatening the health of millions of people in China. The multiple sulfur isotopic composition of sulfate in PM2.5 samples collected in Beijing is used to better constrain potential sources and formation processes of sulfate aerosol. The Δ33S values of sulfate in PM2.5 show a pronounced seasonality with positive values in spring, summer and autumn and negative values in winter. Positive Δ33S anomalies are interpreted to result from SO2 photolysis with self-shielding, and may reflect air mass transport between the troposphere and the stratosphere. The negative Δ33S signature (-0.300‰ < Δ33S < 0‰) in winter is possibly related to incomplete combustion of coal in residential stoves during the heating season, implying that sulfur dioxide released from residential stoves in more rural areas is an important contributor to atmospheric sulfate. However, negative Δ33S anomalies (-0.664‰ < Δ33S ← 0.300‰) in winter and positive Δ33S anomalies (0.300‰ < Δ33S < 0.480‰) in spring, summer, and autumn suggest sulfur isotopic equilibrium on an annual time frame, which may provide an implication for the absence of mass-independent fractionation of sulfur isotopes (S-MIF) in younger sediments. Results obtained here reveal that reducing the usage of coal and improving the heating system in rural areas will be important for efficiently decreasing the emissions of sulfur in China and beyond.
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Affiliation(s)
- Xiaokun Han
- Center for Environmental Remediation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences , 11A Datun Road, Chaoyang, Beijing 100101, China
| | - Qingjun Guo
- Center for Environmental Remediation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences , 11A Datun Road, Chaoyang, Beijing 100101, China
- College of Resources and Environment, University of Chinese Academy of Sciences , Beijing 100049, China
| | - Harald Strauss
- Institut für Geologie und Paläontologie, Westfälische Wilhelms-Universität Münster , Corrensstrasse 24, 48149 Münster, Germany
| | - Congqiang Liu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences , Guiyang Guizhou 550002, China
| | - Jian Hu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences , Guiyang Guizhou 550002, China
| | - Zhaobing Guo
- School of Environmental Science and Engineering, Nanjing University of Information Science and Technology , Nanjing 210044, China
| | - Rongfei Wei
- Center for Environmental Remediation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences , 11A Datun Road, Chaoyang, Beijing 100101, China
| | - Marc Peters
- Center for Environmental Remediation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences , 11A Datun Road, Chaoyang, Beijing 100101, China
| | - Liyan Tian
- Center for Environmental Remediation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences , 11A Datun Road, Chaoyang, Beijing 100101, China
| | - Jing Kong
- Center for Environmental Remediation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences , 11A Datun Road, Chaoyang, Beijing 100101, China
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Han X, Guo Q, Liu C, Strauss H, Yang J, Hu J, Wei R, Tian L, Kong J, Peters M. Effect of the pollution control measures on PM 2.5 during the 2015 China Victory Day Parade: Implication from water-soluble ions and sulfur isotope. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2016; 218:230-241. [PMID: 27423498 DOI: 10.1016/j.envpol.2016.06.038] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Revised: 06/03/2016] [Accepted: 06/18/2016] [Indexed: 05/24/2023]
Abstract
Air pollution by particulate matter is a serious problem in Beijing. Strict pollution control measures have been carried out in Beijing prior to and during the 2015 China Victory Day Parade in order to improve air quality. This distinct event provides an excellent opportunity for investigating the impact of such measures on the chemical properties of particulate matter with an aerodynamic diameter ≤2.5 μm (PM2.5). The water-soluble ions as well as sulfur and oxygen isotopes of sulfate in PM2.5 collected between August 19 and September 18, 2015 (n = 31) were analyzed in order to trace the sources and formation processes of PM2.5 in Beijing. The results exhibit a decrease in concentration of water-soluble ions in PM2.5 including aerosol sulfate. In contrast, the mean values of δ34Ssulfate (4.7 ± 0.8‰ vs. 5.0 ± 2.0‰) and δ18Osulfate (18.3 ± 2.3‰ vs. 17.2 ± 6.0) in PM2.5 during the air pollution control period and the non-source control period exhibit no significant differences, which suggests that despite a reduction in concentration, the sulfate source remains identical for the two periods. It is inferred that the decrease in concentration of sulfate in PM2.5 mainly results from variations in air mass transport. Notably, the air mass during the pollution control period originated mainly from north and northeast and changed to southerly directions thereafter. The sulfur and oxygen isotopes of the sulfate point to coal combustion as the major source of sulfate in PM2.5 from the Beijing area.
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Affiliation(s)
- Xiaokun Han
- Center for Environmental Remediation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qingjun Guo
- Center for Environmental Remediation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China.
| | - Congqiang Liu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang Guizhou 550002, China
| | - Harald Strauss
- Institut für Geologie und Paläontologie, Westfälische Wilhelms-Universität Münster, Corrensstrasse 24, 48149 Münster, Germany
| | - Junxing Yang
- Center for Environmental Remediation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Jian Hu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang Guizhou 550002, China
| | - Rongfei Wei
- Center for Environmental Remediation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Liyan Tian
- Center for Environmental Remediation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jing Kong
- Center for Environmental Remediation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Marc Peters
- Center for Environmental Remediation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
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Xie L, Spiro B, Wei G. Purification of BaSO 4 precipitate contaminated with organic matter for oxygen isotope measurements (δ 18 O and Δ 17 O). RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2016; 30:1727-1733. [PMID: 28328040 DOI: 10.1002/rcm.7610] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2016] [Revised: 05/10/2016] [Accepted: 05/16/2016] [Indexed: 06/06/2023]
Abstract
RATIONALE Sulfate precipitates are often contaminated with nitrates and organic materials (OM), which reduce the precision and accuracy of measurements of δ18 O and Δ17 O values in the sulfate. Although nitrates can be effectively removed using diethylenetriaminepentaacetic acid solution, removing OM from the precipitates is often difficult. One effective approach is to heat powdered precipitates to high temperatures. In this study, the effect of this procedure on the δ18 O and Δ17 O values of BaSO4 precipitate was fully examined. METHODS OM-contaminated BaSO4 precipitates and 18 O- and 17 O-labeled purified BaSO4 precipitates were loaded into alumina and gold crucibles and heated at 450 °C, 600 °C and 800 °C for 2 h. The nitrogen and carbon contents in the initial and the final BaSO4 were measured using an elemental analyzer. The values of δ18 O and Δ17 O were measured using a temperature conversion/elemental analyzer coupled with an isotope ratio mass spectrometer, and a CO2 laser system coupled with an isotopic ratio mass spectrometer. RESULTS OM was effectively (88 ± 17%) removed from the BaSO4 precipitates by this treatment, and heating at 800 °C had the highest removal efficiency (98%). The differences in δ18 O and Δ17 O values between the final and initial BaSO4 precipitates was -0.6‰ to 0.3‰ (average of -0.1‰) and -0.24‰ to 0.10‰ (average of -0.02‰), respectively. Significant positive relationships between the δ18 O and Δ17 O values of the initial BaSO4 precipitate and those of the high-T-treated aliquots were found, with slopes having mean values of 0.96 ± 0.06 and 1.04 ± 0.01, respectively. CONCLUSIONS The result demonstrates high removal efficiency for OM in BaSO4 precipitates and no significant differences in the oxygen isotopic compositions between high-T treated BaSO4 and initial BaSO4 . This study indicates that the modified high-T treatment (800 °C, 2 h) is an effective method for purifying BaSO4 precipitated from geological and environmental samples with a high OM content for δ18 O and Δ17 O measurements. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Luhua Xie
- State Key Laboratory of Isotope Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, P.R. China
- Key Laboratory of Marginal Sea Geology, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, P.R. China
| | - Baruch Spiro
- Department of Mineralogy, Natural Science Museum, London, SW7 5BD, UK
| | - Gangjian Wei
- State Key Laboratory of Isotope Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, P.R. China
- Key Laboratory of Marginal Sea Geology, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, P.R. China
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Lost cold Antarctic deserts inferred from unusual sulfate formation and isotope signatures. Nat Commun 2015; 6:7579. [PMID: 26119082 DOI: 10.1038/ncomms8579] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Accepted: 05/20/2015] [Indexed: 11/08/2022] Open
Abstract
The Antarctic ice cap significantly affects global ocean circulation and climate. Continental glaciogenic sedimentary deposits provide direct physical evidence of the glacial history of the Antarctic interior, but these data are sparse. Here we investigate a new indicator of ice sheet evolution: sulfates within the glaciogenic deposits from the Lewis Cliff Ice Tongue of the central Transantarctic Mountains. The sulfates exhibit unique isotope signatures, including δ(34)S up to +50‰ for mirabilite evaporites, Δ(17)O up to +2.3‰ for dissolved sulfate within contemporary melt-water ponds, and extremely negative δ(18)O as low as -22.2‰. The isotopic data imply that the sulfates formed under environmental conditions similar to today's McMurdo Dry Valleys, suggesting that ice-free cold deserts may have existed between the South Pole and the Transantarctic Mountains since the Miocene during periods when the ice sheet size was smaller than today, but with an overall similar to modern global hydrological cycle.
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Geng L, Schauer AJ, Kunasek SA, Sofen ED, Erbland J, Savarino J, Allman DJ, Sletten RS, Alexander B. Analysis of oxygen-17 excess of nitrate and sulfate at sub-micromole levels using the pyrolysis method. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2013; 27:2411-2419. [PMID: 24097397 DOI: 10.1002/rcm.6703] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Revised: 08/04/2013] [Accepted: 08/05/2013] [Indexed: 06/02/2023]
Abstract
RATIONALE The oxygen-17 excess (Δ(17)O) of nitrate and sulfate contains valuable information regarding their atmospheric formation pathways. However, the current pyrolysis method to measure Δ(17)O requires large sample amounts (>4 µmol for nitrate and >1 µmol for sulfate). We present a new approach employing a Gas Bench interface which cryofocuses O2 produced from sample pyrolysis, enabling the analysis of sub-micromole size samples. METHODS Silver nitrate or sulfate at sub-micromole levels in a sample container was thermally decomposed to O2 and byproducts in a modified Temperature Conversion/Elemental Analyzer (TC/EA). Byproducts (mainly NO2 for silver nitrate and SO2 for silver sulfate) were removed in a liquid nitrogen trap and the sample O2 was carried by ultra-pure helium (He) gas to a Gas Bench II interface where it was cryofocused prior to entering an isotope ratio mass spectrometer. RESULTS Analysis of the international nitrate reference material USGS35 (Δ(17)O = 21.6‰) within the size range of 300-1000 nmol O2 gave a mean Δ(17)O value of (21.6 ± 0.69) ‰ (mean ±1σ). Three inter-laboratory calibrated sulfate reference materials, Sulf-α, Sulf-β and Sulf-ε, each within the size range of 180-1000 nmol O2, were analyzed and shown to possess mean Δ(17)O values of (0.9 ± 0.10)‰, (2.1 ± 0.25)‰ and (7.0 ± 0.63)‰, respectively. CONCLUSIONS The analyses of nitrate and sulfate reference materials at sub-micromole levels gave Δ(17)O values consistent with their accepted values. This new approach of employing the Gas Bench to cryofocus O2 after the pyrolysis of AgNO3 and Ag2SO4 particularly benefits the effort of measuring Δ(17)O in sample types with a low abundance of nitrate and sulfate such as ice cores.
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Affiliation(s)
- Lei Geng
- Department of Atmospheric Sciences, University of Washington, Seattle, WA, USA
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Tales of volcanoes and El-Nino southern oscillations with the oxygen isotope anomaly of sulfate aerosol. Proc Natl Acad Sci U S A 2013; 110:17662-7. [PMID: 23447567 DOI: 10.1073/pnas.1213149110] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The ability of sulfate aerosols to reflect solar radiation and simultaneously act as cloud condensation nuclei renders them central players in the global climate system. The oxidation of S(IV) compounds and their transport as stable S(VI) in the Earth's system are intricately linked to planetary scale processes, and precise characterization of the overall process requires a detailed understanding of the linkage between climate dynamics and the chemistry leading to the product sulfate. This paper reports a high-resolution, 22-y (1980-2002) record of the oxygen-triple isotopic composition of sulfate (SO4) aerosols retrieved from a snow pit at the South Pole. Observed variation in the O-isotopic anomaly of SO4 aerosol is linked to the ozone variation in the tropical upper troposphere/lower stratosphere via the Ozone El-Niño Southern Oscillations (ENSO) Index (OEI). Higher (17)O values (3.3‰, 4.5‰, and 4.2‰) were observed during the three largest ENSO events of the past 2 decades. Volcanic events inject significant quantities of SO4 aerosol into the stratosphere, which are known to affect ENSO strength by modulating stratospheric ozone levels (OEI = 6 and (17)O = 3.3‰, OEI = 11 and (17)O = 4.5‰) and normal oxidative pathways. Our high-resolution data indicated that (17)O of sulfate aerosols can record extreme phases of naturally occurring climate cycles, such as ENSOs, which couple variations in the ozone levels in the atmosphere and the hydrosphere via temperature driven changes in relative humidity levels. A longer term, higher resolution oxygen-triple isotope analysis of sulfate aerosols from ice cores, encompassing more ENSO periods, is required to reconstruct paleo-ENSO events and paleotropical ozone variations.
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Schauer AJ, Kunasek SA, Sofen ED, Erbland J, Savarino J, Johnson BW, Amos HM, Shaheen R, Abaunza M, Jackson TL, Thiemens MH, Alexander B. Oxygen isotope exchange with quartz during pyrolysis of silver sulfate and silver nitrate. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2012; 26:2151-2157. [PMID: 22886811 DOI: 10.1002/rcm.6332] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
RATIONALE Triple oxygen isotopes of sulfate and nitrate are useful metrics for the chemistry of their formation. Existing measurement methods, however, do not account for oxygen atom exchange with quartz during the thermal decomposition of sulfate. We present evidence for oxygen atom exchange, a simple modification to prevent exchange, and a correction for previous measurements. METHODS Silver sulfates and silver nitrates with excess (17)O were thermally decomposed in quartz and gold (for sulfate) and quartz and silver (for nitrate) sample containers to O(2) and byproducts in a modified Temperature Conversion/Elemental Analyzer (TC/EA). Helium carries O(2) through purification for isotope-ratio analysis of the three isotopes of oxygen in a Finnigan MAT253 isotope ratio mass spectrometer. RESULTS The Δ(17)O results show clear oxygen atom exchange from non-zero (17)O-excess reference materials to zero (17)O-excess quartz cup sample containers. Quartz sample containers lower the Δ(17)O values of designer sulfate reference materials and USGS35 nitrate by 15% relative to gold or silver sample containers for quantities of 2-10 µmol O(2). CONCLUSIONS Previous Δ(17)O measurements of sulfate that rely on pyrolysis in a quartz cup have been affected by oxygen exchange. These previous results can be corrected using a simple linear equation (Δ(17)O(gold) = Δ(17)O(quartz) * 1.14 + 0.06). Future pyrolysis of silver sulfate should be conducted in gold capsules or corrected to data obtained from gold capsules to avoid obtaining oxygen isotope exchange-affected data.
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Affiliation(s)
- Andrew J Schauer
- Department of Earth and Space Sciences, University of Washington, Seattle, WA, USA.
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Hill-Falkenthal J, Priyadarshi A, Thiemens M. Differentiating sulfate aerosol oxidation pathways for varying source altitudes using35S and Δ17O tracers. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2012jd018242] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Alexander B, Allman DJ, Amos HM, Fairlie TD, Dachs J, Hegg DA, Sletten RS. Isotopic constraints on the formation pathways of sulfate aerosol in the marine boundary layer of the subtropical northeast Atlantic Ocean. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2011jd016773] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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