A potential formation route for CHOS compounds in dissolved organic matter

Sulfur polyoxygenated organic compounds (CHOS compounds) had been detected in dissolved organic matter (DOM) from several aquatic systems around the world but the knowledge of its origin and geochemical behavior is still scarce. Previous studies have reported correlations between the content of CHOS compounds in DOM and the sulfide concentration in aquatic systems. We therefore performed a set of laboratorial experiments aiming to better understand the role of DOM in the sulfur cycle and we found that CHOS compounds can be formed in aquatic systems by the addition of sulfide/bisulfide ions to lignin-like CHO compounds. We also show that sediments act as heterogeneous catalysts that facilitate the formation of CHOS compounds.