Impact of Nitrogen Input on Volatile Sulfide Emissions From Coastal Wetland Sediments

Abstract Volatile sulfur compounds (VSCs) play a crucial role in regulating global climate change and atmospheric environment. However, the impact of nitrogen input on sulfur cycling in coastal wetland sediments remains unclear. Here, we conducted in situ experiments to explore the impact of inorganic nitrogen on VSC emissions from a salt marsh wetland in Jiaozhou Bay, China along with comparison between Suaeda glauca and mudflat sediment across different seasons. In autumn, we found that the emissions of dimethyl sulfide (DMS) and carbon disulfide (CS 2 ) from sediments covered by S . glauca (DMS and CS 2 fluxes: 29.86 ± 2.23 and 9.94 ± 2.00 nmol m −2 s −1 ) were significantly higher compared to the mudflat sediment (DMS and CS 2 fluxes: −2.94 ± 0.90 and 7.56 ± 3.07 nmol m −2 s −1 ). Conversely, carbonyl sulfide (COS) fluxes were generally lower in S . glauca area (10.5 ± 8.32 nmol m −2 s −1 ) than in mudflat area (23.2 ± 3.58 nmol m −2 s −1 ). In spring, DMS, CS 2 , and COS fluxes in S . glauca area were all lower than those in mudflat area. Moreover, adding nitrogen at soil levels typically led to reduced VSC emissions from S . glauca area in autumn, while, in spring, it increased the emissions of DMS, CS 2 , and COS from mudflat sediments by 221.5%, 243.8%, and 375.0%, respectively. These variations in flux were primarily influenced by microbial activity, sediment temperature, and sulfate levels. In summary, these findings enhance our understanding of soil sulfur cycling in the context of future nitrogen deposition scenarios in coastal wetlands.