Distribution Characteristics of Dimethylated Sulfur Compounds and Turnover of Dimethylsulfide in the Northern South China Sea During Summer

Abstract

Spatial distributions of dimethylsulfide (DMS), dimethylsulfoniopropionate (DMSP), and dimethyl sulfoxide (DMSO) in the northern South China Sea were determined in the summer of 2015. The mean concentrations of DMS, particulate DMSP (DMSPp), dissolved DMSP (DMSPd), dissolved DMSO (DMSOd), and particulate DMSO (DMSOp) in the surface seawater were 2.8 ± 1.0, 6.8 ± 1.5, 14.0 ± 3.1, 12.2 ± 3.2, and 9.2 ± 2.6 nmol L−1, respectively. The contributions of three principal removal pathways of DMS were investigated. The average biological production and consumption rates of DMS in the surface seawater were 6.15 ± 1.12 and 4.63 ± 1.32 nmol L−1 day−1. Deck incubation experiments showed that the photooxidation rates of DMS for different radiation bands followed the order: KUVB > KUVA > Kvisible light. The DMS photooxidation rates were higher in the coastal waters than in the open ocean, which might be associated with the higher concentrations of dissolved organic matter of terrigenous input. The sea‐to‐air fluxes of DMS ranged from 1.6 to 50.3 μmol m−2 day−1 with an average value of 15.6 ± 11.6 μmol m−2 day−1. Based on the respective turnover times of DMS, the contributions of biological consumption, photooxidation, and sea‐to‐air exchange to the sink of DMS were 32.6 ± 11.0%, 23.2 ± 8.9%, and 44.1 ± 19.2%, respectively, suggesting that the three removal pathways were all critical to the migration and transformation of DMS in the surface seawater during summer.

Factors Controlling DMS Emission and Atmospheric Sulfate Aerosols in the Western Pacific Continental Sea

“…(2018) for the same period and season, potentially due to reduced wind speeds and DMS concentrations during the survey period. Furthermore, this study found a significant reduction in DMS sea‐air flux in the South China Sea during autumn compared to spring (Zhai et al., 2020), likely attributable to decreased phytoplankton biomass resulting in lower surface water DMS concentration. The magnitude of the South Sea necessitates acknowledging the significant amount of DMS it emits into the atmosphere.…”

Springtime Spatial Distributions of Biogenic Sulfur Compounds in the Yangtze River Estuary and Their Responses to Seawater Acidification and Dust

“…All DMS samples were measured immediately onboard using the modified purge‐and‐trap method described by Zhai et al. (2020). For DMS, a 2 mL sample was transferred to a purge‐and‐trap system linked to a Shimadzu GC‐2014 gas chromatograph (Tokyo, Japan) equipped with a Teflon glass column (Chromosil 330, Supelco) and a flame photometric detector (Zhai et al., 2020; Zhang et al., 2014).…”

“…All DMS samples were measured immediately onboard using the modified purge-and-trap method described by Zhai et al (2020). For DMS, a 2 mL sample was transferred to a purge-and-trap system linked to a Shimadzu GC-2014 gas chromatograph (Tokyo, Japan) equipped with a Teflon glass column (Chromosil 330, Supelco) and a flame photometric detector (Zhai et al, 2020;Zhang et al, 2014). For dissolved DMSP (DMSPd) and DMSO (DMSOd) samples, two aliquots of 4 ml seawater were gravity filtered through 47-mm Whatman GF/F filters and then fixed with 40 µL of 50% H 2 SO 4 and 20 µL of 25% HCl, respectively.…”

Responses of Biogenic Sulfur Compound Concentrations to Dust Aerosol Enrichment and Ocean Acidification in the Western Pacific Ocean

“…Dissolved DMSP (DMSPd), DMSO (DMSOd), and total DMSP (DMSPt), DMSO (DMSOt) concentrations were measured by conversion to DMS. (Yang et al, 2011;Zhai et al, 2020). Samples for other parameters (e.g., Chl-a, nutrients, dissolved organic carbon (DOC), and phytoplankton abundance) were processed onboard for storage and brought back to the laboratory for analysis.…”