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

Abstract

Dimethylsulfide (DMS) emissions from the ocean contribute approximately 28.1 Tg S yr −1 to the atmosphere, representing 90% of oceanic biogenic sulfur emissions and more than 50% of global biogenic sulfur emissions (Arnold et al., 2013;Lana et al., 2011). DMS is the predominant biogenic sulfur compound, and is produced through the secondary metabolism of dimethylsulfoniopropionate (DMSP) by algal cells (Stefels et al., 2007). DMS has received more interest since the CLAW hypothesis proposed that DMS emissions from the seawater and their effect on climate change are part of a feedback loop (Charlson et al., 1987). When emitted to the atmosphere, DMS is rapidly oxidized to form a variety of sulfur-containing compounds (Zhang et al., 2017). These compounds lead to the formation of aerosol particles that act as cloud condensation nuclei (CCN) in the marine boundary layer (Charlson et al., 1987;Uher et al., 2017), which can impact the global climate (Jian et al., 2017). DMSP, the primary precursor of DMS, is an essential part of the biogeochemical cycle of DMS (Keller et al., 1989). Algal cells release DMSP naturally in small amounts, but its release can be accelerated when the algal cells undergo senescence, grazing, or viral attack (Andreae Abstract The spatial distributions of dimethylsulfide (DMS), dimethylsulfoniopropionate (DMSP), and dimethylsulfoxide (DMSO) were investigated in the Yangtze River Estuary from 9 to 23 March, 2018. The average concentrations of DMS, dissolved DMSP (DMSPd), particulate DMSP (DMSPp), dissolved DMSO (DMSOd) and particulate DMSO (DMSOp) were 3.

Effects of Phytoplankton on the Production and Emission of Estuarine Dimethyl Sulfide Under Different Nutrient Inputs From Changjiang River

“…Compared to previous investigations in the CEECS during spring (flux: 3.21/8.19 μ mol m −2 d −1 ; DMS concentration: 2.81/3.00 nmol L −1 ; wind speed: 4.5/7.3 m s −1 ) and summer (flux: 20.73 μ mol m −2 d −1 ; DMS concentration: 6.55 nmol L −1 ; wind speed: 5.8 m s −1 ) reported by X. Gao et al. (2021) and Jian et al. (2019), our estimated DMS fluxes were obviously lower.…”

“…Compared to previous investigations in the CEECS during spring (flux: 3.21/8.19 μmol m −2 d −1 ; DMS concentration: 2.81/3.00 nmol L −1 ; wind speed: 4.5/7.3 m s −1 ) and summer (flux: 20.73 μmol m −2 d −1 ; DMS concentration: 6.55 nmol L −1 ; wind speed: 5.8 m s −1 ) reported by X. Gao et al (2021) and Jian et al (2019), our estimated DMS fluxes were obviously lower. However, our flux was markedly higher than that in N. Gao et al (2017)'s investigation during summer (flux: 1.70 μmol m −2 d −1 ; DMS concentration: 3.99 nmol L −1 ; wind speed: 2.3 m s −1 ).…”

“…As for the CEECS, only moderate correlations between Chl‐ a and BDSCs were observed, and only in summer. The relationships between Chl‐ a and BDSCs may be highly variable in the CEECS (N. Gao et al., 2017; X. Gao et al., 2021; Jian et al., 2019). In general, the correlations were strongest when the phytoplankton community was dominated by a single, high‐DMSP‐producing species.…”

“…The terrestrial input carried by the Changjiang River provides a nutritional basis for marine ecosystems, making the CEECS one of the most productive areas in the world and, relatedly, a significant net source of atmospheric DMS. Nevertheless, the complex and variable ecological environment leads to unique temporal and spatial distribution patterns of biogenic dimethylated sulfur compounds (BDSCs) in the CEECS (N. Gao et al., 2017; X. Gao et al., 2021; Jian et al., 2019). Also, the significant increases in the spatial range and frequency of harmful algal blooms (S. Gao & Wang, 2008; Liu et al., 2010) impact the biological production of DMSP, consequently resulting in a wide range of DMS concentrations (0.20–29.68 nmol L −1 ) in the CEECS (N. Gao et al., 2017; Jian et al., 2019).…”

“…The terrestrial input carried by the Changjiang River provides a nutritional basis for marine ecosystems, making the CEECS one of the most productive areas in the world and, relatedly, a significant net source of atmospheric DMS. Nevertheless, the complex and variable ecological environment leads to unique temporal and spatial distribution patterns of biogenic dimethylated sulfur compounds (BDSCs) in the CEECS (N. Gao et al, 2017;X. Gao et al, 2021;Jian et al, 2019).…”