The study looked at different types of wetlands in Jiaozhou Bay, China, to see how much soil organic carbon (SOC) they had and how it varied with depth and season. They found that the amount of SOC decreased with depth in most wetlands, but increased slightly in one type. The wetland with Spartina anglica had the highest SOC content, followed by barren wetland, Suaeda glauca wetland, and Phragmites australis wetland. SOC content was highest in spring and lowest in winter. The amount of SOC was related to soil salinity, moisture, TN, and C/N, but inversely related to pH and soil density. The barren wetland had the most carbon stored per unit area, making it an important carbon sink in coastal wetlands.