Exploring the atmospheric sulfur trends and the potential contribution of sulfate-reducing microorganism activities to the atmospheric sulfur budget at Saturna Island, B.C

<p>Anthropogenic and biogenic activities, along with the fluxes of sea salt, volcanic, wildfire and oceanic sulfate-reducing microorganisms (SRM), contribute significantly to the atmospheric sulfur budget.<sup>(1,2)</sup></p><p>There is still uncertainty and debate between studies about the magnitude of the importance of oceanic hydrogen sulfide (H<sub>2</sub>S) produced by SRM, as well as its ability to diffuse to the upper water column and its contribution to the atmospheric sulfur budget. While some studies believe that the majority of H<sub>2</sub>S is re-oxidized and is less likely to reach the atmosphere <sup>(3,4)</sup>, there is evidence of the existence of H<sub>2</sub>S in the upper water columns and even in the atmosphere <sup>(2,5)</sup>. H<sub>2</sub>S produced by SRM, emitted to the atmosphere, along with the anthropogenic sulfur dioxide (SO<sub>2</sub>) and dimethyl sulfide (DMS), undergo atmospheric oxidation processes. Sulfate (SO<sub>4</sub><sup>2-</sup>), as one of the main oxidized products, may nucleate with water vapor, ammonia and organic oxides <sup>(6,7)</sup>, and subsequently grow to bigger particle sizes. These particles affect the climate directly and indirectly and change the radiation balance of the Earth-atmosphere system. <sup>(8,9,10)</sup></p><p>This study assessed the seasonal trends of major atmospheric sulfur species including SO<sub>2</sub>, sulfate, and biogenic and anthropogenic sulfate of gas, aerosol and precipitation samples, collected by Canadian Air and Precipitation Monitoring Network (CAPMoN), Environment of Canada, at Saturna Island, B.C, between 1998-2010. We then explored the oceanic phytoplankton activities and DMS production, based on sulfur isotope composition and found the importance of DMS contribution to the summertime atmospheric sulfur budget. A handful of samples (~10-30%) displayed negative sulfur isotope compositions, outside the range of anthropogenic and biogenic isotope values. Potential factors that could produce such negative sulfur isotope composition values include isotopic fractionation, fluxes from mineral dust events, volcanic eruptions, wildfires and microbial sulfate reduction (MSR). Our study found that MSR was the only feasible explanation for these very negative sulfur isotope compositions in non-sea salt sulfate samples. H<sub>2</sub>S in our study was a 4<sup>th</sup> potential contributor to the atmospheric sulfur budget, along with the 3 major sources of anthropogenic, biogenic DMS, and sea-salt sulfate, in this long-term atmospheric sulfur study.</p><p> </p>

Study on the online detection of atmospheric sulfur via laser induced breakdown spectroscopy

The LIBS detection of sulfur presents particular difficulty because of the high excitation energy of sulfur element and relative weakness of the spectral lines. In this work, a novel laser-induced...

Regional and Urban-Scale Environmental Influences of Oceanic DMS Emissions over Coastal China Seas

Marine biogenic dimethyl sulfide (DMS) is an important natural source of sulfur in the atmosphere, which may play an important role in air quality. In this study, the WRF-CMAQ model is employed to assess the impact of DMS on the atmospheric environment at the regional scale of eastern coastal China and urban scale of Shanghai in 2017. A national scale database of DMS concentration in seawater is established based on the historical DMS measurements in the Yellow Sea, the Bohai Sea and the East China Sea in different seasons during 2009~2017. Results indicate that the sea-to-air emission flux of DMS varies greatly in different seasons, with the highest in summer, followed by spring and autumn, and the lowest in winter. The annual DMS emissions from the Yellow Sea, the Bohai Sea and the East China Sea are 0.008, 0.059, and 0.15 Tg S a−1, respectively. At the regional scale, DMS emissions increase atmospheric sulfur dioxide (SO2) and sulfate (SO42−) concentrations over the East China seas by a maximum of 8% in summer and a minimum of 2% in winter, respectively. At the urban scale, the addition of DMS emissions increase the SO2 and SO42− levels by 2% and 5%, respectively, and reduce ozone (O3) in the air of Shanghai by 1.5%~2.5%. DMS emissions increase fine-mode ammonium particle concentration distribution by 4% and 5%, and fine-mode nss-SO42− concentration distributions by 4% and 9% in the urban and marine air, respectively. Our results indicate that although anthropogenic sources are still the dominant contributor of atmospheric sulfur burden in China, biogenic DMS emissions source cannot be ignored.

Seasonal Changes in Microbial Dissolved Organic Sulfur Transformations in Coastal Waters

The marine trace gas dimethylsulfide (DMS) is the single most important biogenic source of atmospheric sulfur, accounting for up to 80% of global biogenic sulfur emissions. Approximately 300 million tons of DMS are produced annually, but the majority is degraded by microbes in seawater. The DMS precursor dimethylsulfoniopropionate (DMSP) and oxidation product dimethylsulphoxide (DMSO) are also important organic sulfur reservoirs. However, the marine sinks of dissolved DMSO remain unknown. We used a novel combination of stable and radiotracers to determine seasonal changes in multiple dissolved organic sulfur transformation rates to ascertain whether microbial uptake of dissolved DMSO was a significant loss pathway. Surface concentrations of DMS ranged from 0.5 to 17.0 nM with biological consumption rates between 2.4 and 40.8 nM·d−1. DMS produced from the reduction of DMSO was not a significant process. Surface concentrations of total DMSO ranged from 2.3 to 102 nM with biological consumption of dissolved DMSO between 2.9 and 111 nM·d−1. Comparisons between 14C2-DMSO assimilation and dissimilation rates suggest that the majority of dissolved DMSO was respired (>94%). Radiotracer microbial consumption rates suggest that dissimilation of dissolved DMSO to CO2 can be a significant loss pathway in coastal waters, illustrating the significance of bacteria in controlling organic sulfur seawater concentrations.

Environmental Concerns and the Importance of Desulfurization

The increased utilization of fossil fuels and subsequent industrialization in most of the world has led to a remarkable increase in the atmospheric sulfur compounds concentrations. Pollution released by the use of petroleum-based fuels contributes immensely to the deterioration of air quality despite regulatory and technological advances in place. SOx, NOx, and particulate matter are constantly emitted to the environment which affects public health, ecosystem, and general wellbeing of the people living mostly in urban areas. Sulfur dioxide, which is the immediate sulfur compound found in the lower atmosphere after combustion of fuels, has a major role to play in the formation of acid rain, smog formation, and particulate aerosols. Each of these formations affects the healthy living of animals, plants, soils, water, and the general ecosystem. This chapter discusses the environmental issues of sulfur.

Surface lanthanide activator doping for constructing highly efficient energy transfer-based nanoprobes for the on-site monitoring of atmospheric sulfur dioxide

A highly efficient, energy transfer-based upconversion nanoprobe was developed, which allowed a portable and visually intuitive detection of gaseous SO2 by use of a smartphone-based detection platform.