Dimethyl Sulfide Removal Research Articles

Enhancement of dimethyl sulphide separation during wort boiling by a single spinning cone evaporator

Wort boiling is the most energy intensive stage in the brewing process. Novel wort boiling systems have been explored to reduce primary energy consumption and improve wort quality and beer flavor stability. Low thermal stress boiling is proposed for wort boiling, but the content of dimethyl sulphide (DMS) in the wort may exceed the required product threshold. A single spinning cone evaporator (SCE) is proposed to enhance the separation of DMS and minimise the energy consumption for wortboiling. The performance of a SCE was evaluated by measurement of fluid flow, ratio of DMS removal, wort self-evaporation ratio based on sensible heat, and thermal efficiency. The results show that use of a spinning cone evaporator, reduced DMS by up to 90% with 2.1% wort self evaporation ratio with less primary heat consumption. The SCE operation exceeds the evaporation of a gravity film cone. Under reduced pressure, the spinning cone evaporator was less effective in DMS removal.

Roles of phytoplankton, microzooplankton, and bacteria in DMSP and DMS transformation processes in the East China Continental Sea

The trace gas dimethylsulfide (DMS) and its precursor dimethylsulfoniopropionate (DMSP) are the most abundant oceanic biogenic organosulfur molecules. Phytoplankton, zooplankton, and bacteria are the most vital biotic factors controlling DMSP and DMS, but their relative effects on the transformation processes still remain uncertain due to their complex biogeochemistry. Here, we provided the relative transformation rates of DMSP and DMS, and their relationships with phytoplankton, microzooplankton, and bacteria in the East China Continental Sea in the summer of 2018. The phytoplankton was the major DMSP producer, contributing 89.8% of DMSP stock with the particulate DMSP production rate at 42.0 nmol L−1 d−1. The DMSP lyase activity was 140.5 nmol DMS L−1h−1, resulting in a short DMSP fate (0.8 d). The microzooplankton grazing resulted in DMSP loss and DMS production at the rates of −49.3 and 8.2 nmol L−1 d−1, equaling 60.0% of total DMSP loss and 71.6% of DMS microbial production. The dissolved DMSP degradation and DMS microbial production rates were at −23.4 and 11.5 nmol L−1 d−1, largely controlled by bacterial abundance. Microbial consumption, photolysis, and ventilation accounted for 41%, 43%, and 16% of surface DMS removal, indicating that most of the DMS was consumed within the surface. Finally, DMS was enriched in the sediment but not significantly enriched in the surface microlayer, with enrichment factors at 3.7 and 1.0, respectively. The budget model in this study could help better estimate the roles of phytoplankton, microzooplankton, and bacteria in DMSP and DMS transformation processes in the continental shelf seas.

Distribution and physical–biological controls of dimethylsulfide in the western tropical Indian Ocean during winter monsoon

New field observation on distribution, turnover, and sea–air flux of three dimethylated sulfur compounds (dimethylsulfide (DMS), dimethylsulfoniopropionate, and dimethylsulfoxide) in the western tropical Indian Ocean (WTIO; 4°N–10°S, 61°–65°E) were conducted under the major Global Change and Air–Sea Interaction Program during the 2021/2022 Northeast Monsoon (December 21, 2021 to January 11, 2022). Significantly high surface concentrations of DMS were identified in the region of the Seychelles–Chagos Thermocline Ridge (SCTR; 5°–10°S). This occurred because the shallow thermocline/nitracline and associated upwelling fueled biological production of DMS in the subsurface, which was brought to the surface through vertical mixing. The calculated sea–air DMS flux was also significantly strong in the SCTR region during the Northeast Monsoon owing to combination of high wind speed and high surface concentration of DMS. This finding is similar to results obtained previously during the Southwest Monsoon, suggesting that the SCTR region is an area of active DMS emission during both the Northeast Monsoon and the Southwest Monsoon. Microbial consumption was the dominant pathway of DMS removal, accounting for 74.4% of the total, whereas the processes of photolysis (17.7%) and ventilation (7.9%) were less important. Future work should be undertaken in the WTIO to establish how DMS emission is linked to aerosol properties and climate change.

Regenerative One-Stage Catalytic Absorption Process with Cupric Ions for Removal of Reduced Sulfur Compounds in Polluted Air

Reduced volatile sulfur compounds emitted from e.g. livestock production and biogas production facilities contribute to general air pollution and local odor nuisance. Improved technologies are required to mitigate the emissions of both hydrogen sulfide and organic sulfur compounds. The present study examines the oxidative absorption of reduced sulfur compounds, i.e. hydrogen sulfide, methanethiol and dimethyl sulfide in a wet oxidation process with cupric chloride. It was found that this process efficiently removes both hydrogen sulfide and methanethiol with removal efficiencies >94% under all process conditions tested, while the removal of dimethyl sulfide was in the range 20-40%. The main products determined were dimethyl disulfide, dimethyl trisulfide and elemental sulfur. It was shown that the process was more efficient than the similar process with ferric ions and higher removal could be obtained with lower residence times. Furthermore, though employing cupric ion as metal catalysts results in the production of gaseous sulfur compounds, it is estimated that this process is efficient for deodorization due to the higher odor threshold values of the product compounds and the pH range is optimal for gas streams containing CO2.

Ozone Catalytic Oxidation for Gaseous Dimethyl Sulfide Removal by Using Vacuum-Ultra-Violet Lamp and Impregnated Activated Carbon

Gaseous sulfur compounds are emitted from many facilities, such as wastewater facilities or biomass power plants, due to the decay of organic compounds. Gaseous dimethyl sulfide removal by ozone catalytic oxidation was investigated in this study. A Vacuum-Ultra-Violet (VUV) xenon excimer lamp of 172 nm was used for ozone generation without NOx generation, and activated carbon impregnated with iodic acid and H2SO4 was utilized as a catalyst. Performance assessment of dimethyl sulfide removal ability was carried out by a dynamic adsorption experiment. Empty-Bed-Contact-Time (EBCT), superficial velocity, concentration of dimethyl sulfide, temperature and humidity were set at 0.48 s, 0.15 m/s, 3.0 ppm, 25 °C and 45%, respectively. Without ozone addition, the adsorption capacity of impregnated activated carbon was 0.01 kg/kg. When ozone of 7.5 ppm was added, the adsorption capacity of impregnated activated carbon was increased to 0.15 kg/kg. Methane sulfonic acid, a reaction product of dimethyl sulfide and ozone, was detected from the activated carbon. The results suggest that the VUV and activated carbon impregnated with iodic acid and H2SO4 are workable for ozone catalytic oxidation for gas treatments.

Transformation processes of biogenic dimethylated sulfur compounds in the northwestern Pacific continental sea

AbstractBiogenic dimethylated sulfur compounds, comprising dimethylsulfide (DMS), dimethylsulfoniopropionate (DMSP), and dimethylsulfoxide, play a vital role in the physiological metabolism processes of marine algae, climate regulation, and global sulfur cycles, but the contribution of each transformation pathway and the factors that control them remain uncertain. For the first time, from 27 March 2017 to 15 April 2017, the rates of major transformation pathways of biogenic dimethylated sulfur compounds and the fluxes of DMS at the sea–air and seawater–sediment interfaces were measured simultaneously in the East China Continental Sea. Rapid biological turnover times of total DMSP (0.53 d), dissolved DMSP (0.29 d), and DMS (0.43 d) were observed, indicating that DMS and DMSP were renewed more than twice daily. Bacterial consumption contributed nearly 50% of the total DMSP loss, approximately 38% of which was converted into DMS. Microbial consumption, photolysis, and ventilation accounted for 56%, 34%, and 10% of DMS removal processes, respectively. Sediment had a small but positive flux of DMS, making the sediment‐seawater interface a tiny source of DMS to the water column. Finally, although only about 10% of DMS was emitted to the atmosphere, the study region was identified as a “hotspot” for atmospheric DMS. The DMS budget model of the mixed layer developed in this study has provided a systematic and comprehensive understanding of the organosulfur cycle in continental shelf seas.

Occurrence and cycle of dimethyl sulfide in the western Pacific Ocean

AbstractOceanic production and occurrence of dimethyl sulfide (DMS) and its subsequent ventilation to the atmosphere significantly contribute to the global sulfur cycle and impact the climate regulation. Spatial distributions of DMS, dimethylsulfoniopropionate (DMSP, precursor of DMS), and dimethyl sulfoxide (DMSO, oxidation product of DMS), production and removal processes of DMS (including biological production, microbial consumption, photo‐degradation, and sea‐to‐air exchange), and biogenic contributions to the atmospheric sulfate burden were simultaneously studied in the western Pacific Ocean during winter. Sea surface DMS, DMSP, and DMSO were strongly correlated and had similar distribution patterns. The DMS photo‐degradation efficiency ratio (normalized using incident photon flux density) for ultraviolet B radiation (UVB): ultraviolet A radiation (UVA): photosynthetically active radiation (PAR) was 391: 36: 1. However, considering the solar spectral composition, the actual contributions of UVB, UVA, and PAR to DMS photo‐degradation in surface waters were 40.6% ± 10.7%, 41.2% ± 15.6%, and 18.2% ± 7.2%, respectively. When integrated across the entire mixed layer, UVA and PAR became the dominant drivers, accounting for 45.2% ± 18.0% and 38.0% ± 17.3% of DMS photo‐degradation, respectively, as UVB was significantly attenuated in seawater. The DMS budget of the entire mixed layer indicated that microbial consumption, photo‐degradation, and ventilation accounted for about 74.3% ± 11.9%, 19.3% ± 9.3%, and 6.5% ± 4.0% of total DMS removal, respectively. Even if ventilation was a minor DMS removal pathway, DMS emissions still contributed approximately 45.2% ± 25.6% of the atmospheric non‐sea‐salt sulfate burden over the western Pacific Ocean.

Formation of Formaldehyde and Other Byproducts by TiO2 Photocatalyst Materials

Photocatalysts promised to control pollution in an environmentally benign manner, inexpensively, and with a low or cheap energy input. However, the limited chemical activity of photocatalysts has prevented their widespread use. This limitation has two important consequences; in addition to limited removal efficiency for pollution, photocatalysts may also generate unwanted byproducts due to incomplete reaction. This study focuses on the byproducts formed in the photocatalytic degradation of dimethyl sulfide (DMS) on titanium dioxide (TiO2), using a continuous flow reactor and detection via proton transfer reaction mass spectrometry. TiO2, activated carbon (AC), TiO2/AC (1:1) and TiO2/AC (1:5) were tested using either a laser-driven light source or LED lamps at 365 nm. The samples were characterized using a N2-BET surface area and pore size distributions, Scanning Electron Microscopy, X-ray Diffraction, and X-ray Photoelectron Spectroscopy, which confirmed that TiO2 was successfully coated on activated carbon without unexpected phases. TiO2 and activated carbon showed different removal mechanisms for DMS. The maximum yield of formaldehyde, 11.4%, was observed for DMS reacting on a TiO2/AC (1:5) composite operating at a DMS removal efficiency of 31.7% at 50 ∘C. In addition to formaldehdye, significant products included acetone and dimethyl disulfide. In all, observed byproducts accounted for over half of the DMS material removed from the airstream. The TiO2/AC (1:5) and TiO2/AC (1:1) composites have a lower removal efficiency than TiO2, but a higher yield of byproducts. Experiments conducted from 20 ∘C to 70 ∘C showed that as temperature increases, the removal efficiency decreases and the production of byproducts increases even more. This is attributed both to decreased surface activity at high temperatures due to increased recombination of reactive species, and to the decreased residence time of volatile compounds on a hot surface. This study shows that potentially dangerous byproducts are formed by photocatalytic reactors because the reaction is incomplete under the conditions generally employed.

Removal of dimethyl sulfide by post-plasma catalysis over CeO2-MnOx catalysts and reaction mechanism analysis

The combination of a multistage rod plasma reactor and post CeO2-MnOx catalysts is studied to treat dimethyl sulfide (DMS). The physicochemical properties of all catalysts and the effect of the catalytic performance of CeO2-MnOx catalysts on DMS removal efficiency are studied. Placing CeO2-MnOx catalysts after the non-thermal plasma system can improve the capability of DMS degradation. The results exhibit that CeO2-MnOx (1:1) catalyst presents a higher catalytic activity than that of CeO2, MnOx, CeO2-MnOx (1:0.5) and CeO2-MnOx (1:3). At the power of 21.7 W, the combination of dielectric barrier discharge and CeO2-MnOx (1:1) catalyst could improve the DMS removal efficiency and CO2 selectivity by 16.2% and 18.2%, respectively. This result maybe closely related with its specific surface area, redox properties and oxygen mobility. In addition, the degradation mechanism of DMS over CeO2-MnOx catalysts is proposed. Finally, the stability of the CeO2-MnOx (1:1) catalyst is investigated, and the reason for the decreased activity of the used catalyst is analyzed.

Simultaneous removal of ammonia and volatile organic compounds from composting of dead pigs and manure using pilot-scale biofilter

ABSTRACT Odor emission is one of the most common problems associated with dead animals composting. Biofiltration treatment for eliminating exhaust odors formed during dead pigs and manure composting has been studied. The composting and biofiltration process consisted of two series of tests. Composting experimental trials lasted 6 weeks, and composting was performed using six pilot-scale reactor vessels. A total of 37 kinds of volatile organic compounds (VOCs) present in the air were identified, and temporal variations were determined during the 42 days of composting. Dimethyl sulfide (DMS), dimethyl disulfide (DMDS), dimethyl trisulfide (DMTS), and trimethylamine (TMA) were identified as the main odors VOCs component according to odor active values (OAVs). Nine biofilter vessels containing mature compost were used in studying the effect of different (30, 60, and 100 s) empty bed retention times (EBRT) on the simultaneous removal efficiencies (REs) of NH3, DMS, DMDS, DMTS, and TMA. Results indicated that the inlet concentration of NH3 applied was 12–447 mg m−3, and the average removal efficiencies were 85.4%, 88.7%, and 89.0% for EBRTs of 30, 60, and 100 s, respectively. The average REs of DMS, DMDS, DMTS, and TMA were 79.2%–95.4%, 81.9%–94.0%, 76.7%–99.1%, and 92.9%–100%, respectively, and their maximum elimination capacity (ECs) were 220, 1301, 296, and 603 mg m−3 h−1, respectively. The optimal EBRT for the stimulation removal of NH3, DMS, DMDS, DMTS, and TMA was 60 s. Implications: Dimethyl sulfide (DMS), dimethyl disulfide (DMDS), dimethyl trisulfide (DMTS), and trimethylamine (TMA) were identified as the main odors VOCs component during dead pigs and manure composting. Biofilter with mature as media can be used to stimulation remove NH3, DMS, DMDS, DMTS, and TMA, the optimal empty bed retention times EBRT was 60 s.

Direct observation of dimethyl sulfide trapped by MOF proving efficient removal of sulfur impurities.

Here, we report the adsorptive removal of trace amounts of dimethyl sulfide (DMS) using metal–organic frameworks (MOFs). Cu2+-based MOFs with open metal sites (OMSs), [Cu3(btc)2] (HKUST-1), where btc = 1,3,5-benzenetricarboxylate, and without OMSs, [Cu2(bdc)2(dabco)] (Cu-JAST-1), where bdc = 1,4-benzenedicarboxylate and dabco = 1,4-diazabicyclo[2.2.2]octane, were investigated for the removal of DMS to compare their performance with that of Ag–Y zeolite, which is currently widely used in industry. HKUST-1 exhibited a considerably higher adsorption capacity for DMS than the other adsorbents, which was confirmed by breakthrough measurements. The adsorption state of DMS with HKUST-1 was directly revealed by single-crystal X-ray diffraction (SXRD) analysis and in situ Raman spectroscopy. In addition, it was shown that DMS can be removed by HKUST-1 even under humid conditions.

Simultaneous methanethiol and dimethyl sulfide removal in a single-stage biotrickling filter packed with polyurethane foam: Performance, parameters and microbial community analysis.

The bio-treatment of methanethiol (MT) and dimethyl sulfide (DMS), the most common sulfur compounds in odorous gas, is difficult due to the inhibition of DMS degradation by MT. This article investigated the treatment of MT and DMS odorous gas using a single-stage biotrickling filter (BTF) packed with polyurethane foam cubes that were inoculated with activated sludge from a sewage treatment plant operating an anaerobic/aerobic/oxic (AAO) process. The BTF system lasted for 161 days (with 9 days to startup) under an empty gas residence time of 39s. The elimination capacities for MT and DMS were 85.2g/m3/h (removal efficiency=96.6%) and 6.4g/m3/h (removal efficiency=95.0%), respectively, and the maximal elimination capacities of MT and DMS were 119.7g/m3/h and 7.3g/m3/h, respectively. The optimal parameters were as follows: empty bed retention time, 39s; pH, 6.1; recirculation medium flow rate, ≥1.2m3/m2/h; temperature, 29-36°C; and SO42- concentration, < 2.0g-SO42-/L. Microbial community analysis revealed that spatial differentiation between MT-degrading bacteria and DMS-degrading bacteria enable the single-stage BTF can simultaneously remove MT and DMS. The activated sludge of AAO process can be used as the inoculation sludge to treating MT and DMS gas, which provides an important reference for the industrial application of treating odorous gas containing MT and DMS.

Distribution, Occurrence, and Fate of Biogenic Dimethylated Sulfur Compounds in the Yellow Sea and Bohai Sea During Spring

AbstractThe spatial distributions of biogenic dimethylated sulfur compounds (BDSCs), including dimethylsulfide (DMS), dimethylsulfoniopropionate (DMSP), and dimethylsulfoxide, were determined in the Yellow Sea and Bohai Sea during a survey in April–May 2014 and the occurrence and fate of BDSCs in the surface seawater were investigated. The concentrations of DMS and DMSP were significantly correlated with the stocks of chlorophyll a and a decreasing trend was observed from the inshore to the offshore areas. In situ incubation experiments indicated that more than half of the degraded dissolved DMSP (DMSPd) was transformed into DMS. Irradiation experiments showed that the photooxidation of DMS under ultraviolet B, ultraviolet A, and visible light accounted for 23.9%, 71.8%, and 4.3% of the total photooxidation of DMS, respectively. The sea‐to‐air fluxes of DMS ranged from 0.24 to 34.11 μmol m−2 day−1 with a mean of 8.84 μmol m−2 day−1. A comparison of the DMS production rate and main removal rates indicated that bioproduction cannot completely maintain the removal of DMS and might not be the only but the primary source of DMS in the surface seawater. Additionally, the average turnover times of microbial consumption, photooxidation, and sea‐to‐air exchange of DMS were 1.53, 1.16, and 4.28 day and the contributions of the three removal pathways were 40.0%, 41.2%, and 18.8% respectively; this indicated that microbial consumption and photooxidation played dominant roles in controlling the removal of DMS from the surface seawater.

Removal of dimethyl sulphide via a bio-scrubber under anoxic conditions

ABSTRACTThe removal performance of dimethyl sulphide (DMS) by anoxic laboratory-scale bio-scrubber was studied under different operation conditions for 315 days. DMS removal in bio-scrubber system was performed by controlling and changing the operation parameters, including inlet concentration, empty bed residence time (EBRT) and spraying density (SD) of irrigation. Best conditions in the system were achieved for SD of 0.18 m3/m2 h within EBRT of 40 s at an inlet gas concentration of 150 mg/m3 in which 93% of waste gas stream was removed in the bio-scrubber column and bio-degradation in the bio-reactor tank led to 89% of DMS removal from the transferred bio-reactor, while 91.5% of input chemical oxygen demand (COD) was successfully removed. The use of closer values of the average experimental yield to the theoretical value (YNO3/NO3−) of 0.74 led to the production of elemental sulphur (S°) and other sulphur forms rather than sulphate (SO42−) , which was also was recognized as a pale-yellow coloured substance of S° that appeared within the biomass.

Development of oxide-supported nickel-based catalysts for catalytic decomposition of dimethyl sulfide

We have developed a heterogeneous catalyst for the decomposition and removal of dimethyl sulfide used as an odorant in fuels such as city gas in residential fuel cell systems. For the dimethyl sulfide decomposition at 500 °C over various oxides such as γ-Al2O3, TiO2, ZrO2, CeO2, SiO2, and MgO, it was found that adsorption of dimethyl sulfide and other products containing sulfur components, sulfurization of metal oxides, and decomposition of dimethyl sulfide occurred. Namely, dimethyl sulfide could be removed from the reaction gas by several reactions. Furthermore, the loading of the nickel component on γ-Al2O3 as a metal component led to high decomposition performance. Based on the XRD, H2-TPR, and UV–Vis spectra analyses, after the preparation, this catalyst exists in the state of nickel oxide and nickel aluminate supported on γ-Al2O3. However, upon exposure to the dimethyl sulfide or hydrogen sulfide feed, the sulfurization reaction of nickel species proceeds, leading to the transformation of the material to nickel sulfide and the enhancement of the decomposition reaction. Furthermore, based on the results of the optimization of the nickel loading amount, we revealed that the 10 wt% supported catalyst was the best catalyst.

Modeling of Dimethyl Sulfide Stripping Behavior When Applying Delayed Onset of Boiling during Wort Boiling

The response surface methodology, using the central composite design as a tool for modeling, was used to study the impact of two parameters (power supply and boiling time) and their effect on dimethyl sulfide (DMS) removal during wort boiling, when applying delayed onset of boiling. It was observed that the two parameters were significantly impacting the DMS removal with a 21% contribution for power supply and a 58% contribution for the boiling time (P = 0.000 for both). The interaction of the two factors was also significant (P = 0.008) with a contribution of 7%. With the S-methyl methionine conversion to DMS following the pseudo first-order kinetics reaction, k1 was computed as 0.0054 min−1, and the values of k2 were between 0.0151 and 0.407 min−1. After several statistical analyses, we learned that the results coming from the theoretical equations for DMS removal at each studied power supply were not significantly different from the experimental value obtained in the laboratory, validated by the use of these equations. The time spent to reach the residual DMS target of 30, 50, and 100 ppb was 141–377, 94–295, and 60–197 min, respectively, and the energy used to reach the same target was 11.31–12.69, 8.46–8.85, and 5.40–5.91 MJ, respectively.

Removal of Volatile Sulfur Odor by the Biotrickling Filter

The biodegradation of gas-phase mixtrue of dimethyl sulfide (DMS) and 1-propanethiol (PT) was examined in a biotrickling filter (BTF), inoculated with a microbial consortium composed of activated sewage sludge, and pure strains of Alcaligenes sp. SY1 and Pseudomonas putida. S-1. BTF could be successfully started up within only 11 days when the inlet concentrations of DMS and PT were both 50 mg·m-3 and EBRT was 30 s, with 90% removal efficiency (RE) of DMS and 100% RE of PT. In the steady state, the maximum elimination capacities of DMS and PT were 8.7 g·(m3·h)-1 and 12.4 g·(m3·h)-1, respectively. The presence of PT with a concentration up to 51 mg·m-3 showed an antagonistic removal pattern for DMS, but the opposite did not occur. Meanwhile, the BTF showed high efficiency in the biodegradation of H2S. When the concentration of H2S was as high as 230 mg·m-3, the RE of H2S could reach 98%. However, H2S showed a declining effect on the removal of DMS when the concentration exceeded 115 mg·m-3.

Derivation and Application of a Simultaneous Volatile Formation and Stripping Kinetics Equation for Wort Boiling

The paper showed the derivation of an equation to represent simultaneous dimethyl sulfide (DMS) formation and stripping during wort boiling. It also demonstrated a framework of linearization techniques for the resulting equation, which should facilitate its implementation. DMS formation and stripping were modelled by first-order rate equations with the rate constants k1 and k2 representing the rate constants for rate of DMS formation and DMS removal via stripping, respectively. The simultaneous processes of DMS formation and stripping were represented using an instantaneous differential mass balance. The resulting solution was seen to be similar to an equation stated previously by Mitani et al. Linearization of the derived simultaneous DMS formation and stripping model was done using a MacLaurin series coming from Taylor's series expansion.

Catalytic Oxidation of Dimethyl Sulfide Over Commercial V-W/Ti Catalysts: Plasma Activation at Low Temperatures

This paper investigated the enhancement of plasma on dimethyl sulfide (DMS) removal over commercial V-W/Ti catalysts. The effects of catalyst composition, discharge power, and gas temperature on DMS removal in the plasma-based system were analyzed. The results showed that the V0.9–W/Ti catalyst exhibited the best performance toward DMS removal due to its highest reducibility among the employed samples. The introduction of plasma exhibited a synergistic effect on catalysts and significantly enhanced the removal of DMS over the studied temperature range, especially in high discharge power cases. The activation energy $E_{a}$ of DMS removal in the presence of plasma was dramatically reduced to less than 10% of the catalysis only case, indicating different DMS removal pathways in plasma-activated catalysis system. The reaction mechanisms of DMS were also discussed based on the reaction products.

Processes driving seasonal variability in DMS, DMSP, and DMSO concentrations and turnover in coastal Antarctic waters

AbstractThis study presents new measurements of the concentrations and turnover rates of dimethyl sulfide (DMS), dimethylsulfoniopropionate (DMSP), and dimethyl sulfoxide (DMSO) in coastal waters near Palmer Station, Antarctica, during the spring and summer of 2012–2013. Using several novel analytical and experimental techniques, we document variability in DMS, DMSP, and DMSO (DMS/P/O) concentrations and quantify dominant production and removal terms in the mixed layer DMS budget. Our results demonstrate considerable seasonal variability in the concentration of DMS (range 0–20 nM), total DMSP (8–160 nM), and total DMSO (4–160 nM). Over the seasonal cycle, dissolved DMSP concentrations were well correlated with total DMSP concentrations and the abundance of Phaeocystis antarctica, while DMSO concentrations (total and dissolved) were well correlated with DMS concentrations. DMSP cleavage from the dissolved pool (mean rate = 5.5 nM d−1) and release from microzooplankton grazing (mean 5.6 nM d−1) were the dominant sources of DMS, with smaller DMS production rates associated with DMSO reduction from the dissolved pool (mean 2.6 nM d−1) and krill grazing (mean 0.82 nM d−1). Specific rate constants for DMSP cleavage were inversely related to net primary production. Bacterial uptake was a primary contributor to DMS removal (mean −12 nM d−1), and we observed a significant correlation between bacterial production and gross DMS loss rate constants. Estimated sea‐air flux and photo‐oxidation constituted secondary DMS sinks. Our experimental and analytical methods provide insight into the DMS/P/O cycle at Palmer Station, and a starting point for future studies examining inter‐annual DMS/P/O variability in coastal Antarctic waters.