Neglected Biogeochemical Process for Ocean Health: Seagrass Detritus Simultaneously Enhances Phenolic Endocrine-Disrupting Chemical Capture and Organic Carbon Sequestration

This study presents the first comprehensive investigation on an easily neglected biogeochemical process of phenolic endocrine-disrupting chemical (EDC) capture and carbon sequestration by seagrass detritus. The results showed that Zostera marina L. detritus captured nonylphenol (NP) and bisphenol A (BPA) with high efficiency (>90%) and enhanced organic carbon sequestration in marine ecosystems. Under various seawater-sediment scenarios (pure seawater, nonburial, and burial systems), phenolic EDC rerelease rates were low (<20%), while total organic carbon (TOC) stocks increased by 21.5%-28.8% in EDC-treated groups compared to controls. Kinetic analyses revealed that NP and BPA were rapidly captured onto heterogeneous active sites of the detritus surface, with capture efficiency influenced by the physicochemical properties of contaminants, environmental factors, and the specific characteristics of the detritus. Laser scanning confocal microscopy (LSCM) and density functional theory (DFT) were employed to investigate synergistic mechanisms between phenolic EDCs and carbon at cellular and molecular levels. The lipids mediated NP sequestration through hydrophobic interactions with lipid-rich sites (such as phospholipids), while polysaccharides facilitated BPA binding via electrostatic interactions, highlighting their crucial roles in capturing phenolic EDCs. These findings reinforced the importance of seagrass meadows in capturing emerging contaminants and storing carbon in marine ecosystems.