While seagrass meadows are perceived to be pertinent blue carbon reservoirs, they also potentially release methane (CH₄) into the atmosphere. Seasonal and diurnal variations in CH₄ emissions from a subtropical hypersaline lagoon dominated by Halodule wrightii in southern Texas, USA, on the northwest coast of the Gulf of Mexico were investigated. Dissolved CH₄ concentrations decreased in the daytime and increased overnight during the diel observation period, which could be explained by photosynthesis and respiration of seagrasses. Photosynthetic oxygen was found to significantly reduce CH₄ emissions from seagrass sediment. Diffusive transport contributed slightly to the release of CH₄ from the sediment to the water column, while plant mediation might be the primary mechanism. The diffusive CH₄ flux at the sea-air interface was 12.3–816.2 µmol/m² d, over the range of the sea-air fluxes previously reported from other seagrass meadows. This was related to relatively higher dissolved CH₄ concentrations (11.6–258.2 nmol/L) in a mostly closed lagoon with restricted water exchange. This study emphasizes seagrass meadows in the subtropical hypersaline lagoon as a source of atmospheric CH₄, providing insights into the interactions between seagrass ecosystems and methane dynamics, with potential implications for seagrass meadow management and conservation efforts.

虽然海草草甸被认为是相关的蓝碳库，但它们也可能将甲烷 (CH ₄ ) 释放到大气中。对美国德克萨斯州南部墨西哥湾西北海岸以Halodule wrightii为主的亚热带高盐泻湖CH ₄排放量的季节和日变化进行了调查。在昼夜观测期间，溶解的CH ₄浓度白天下降，夜间上升，这可以通过海草的光合作用和呼吸作用来解释。研究发现光合氧可显着减少海草沉积物中的CH _{4排放。扩散迁移对CH 4}从沉积物释放到水体中的贡献较小，而植物介导可能是主要机制。海-气界面的CH ₄扩散通量为12.3–816.2 µmol/m ²  d，超出了之前报道的其他海草草甸的海-气通量范围。这与水交换受限且大部分封闭的泻湖中溶解的 CH ₄浓度相对较高（11.6–258.2 nmol/L）有关。本研究强调亚热带高盐泻湖中的海草草甸作为大气 CH ₄的来源，深入了解海草生态系统与甲烷动态之间的相互作用，对海草草甸管理和保护工作具有潜在影响。