Spartina alterniflora raised soil sulfide content by regulating sulfur cycle-associated bacteria in the Jiuduansha Wetland of China

Purpose The Spartina alterniflora invasion across the southeast coast in China significantly reduced vegetation diversity and generated associated ecological problems. Sulfur (S) is a vital nutrient, while sulfide is phytotoxic and the impact of S. alterniflora invasion on soil S cycle remains unclear. Therefore, this study aims to investigate the impacts of S. alterniflora invasion on the S cycle and associated soil microbial communities. Methods Both field investigation and lab-scale experiments were conducted, analyzing soil sulfide and sulfate contents, soil properties over four seasons in the Jiuduansha Wetland of Shanghai, China, the high-throughput sequencing of soil microbial communities, S cycle-related functional genes and seed germination experiments. Results The contents of sulfide, soil organic carbon (SOC), and total nitrogen (TN) in the bulk soil of S. alterniflora invaded area were higher than those in the native species S. mariqueter habitat and bare mudflat soils. Spartina alterniflora invasion increased the abundance of the Nitrospiraceae and Desulfarculaceae families and reduced that of Hydrogenophilaceae. The relative abundance of the SO42- reduction functional genes (dsrA + dsrB) in the soil was increased after S. alterniflora invasion, while that of the S oxidation functional genes (yedZ + soxY) in the soil was reduced. Seed germination experiments with different sodium sulfide concentrations (Na2S) revealed that the phytotoxicity of sulfide caused more lethal damage to S. mariqueter than to S. alterniflora. Conclusion The S. alterniflora invasion significantly increased SOC and TN contents and reduced the abundance of sulfur-oxidizing functional genes, which led to the accumulation of soil sulfide.

Automated summary

The invasion of Spartina alterniflora led to an increase in sulfide, soil organic carbon, and total nitrogen contents, while reducing the abundance of sulfur-oxidizing functional genes, resulting in the accumulation of soil sulfide.