Effects of Sesuvium portulacastrum Floating Treatment Wetlands on Nitrogen Removal and Carbon Sequestration in Aquaculture Water

Sesuvium portulacastrum floating treatment wetlands (FTWs) are effective at removing nitrogen and phosphorus, adsorbing heavy metals, and removing organic pollutants from aquaculture wastewater, and thus improve fish farming productivity. In this study, an S. portulacastrum FTW was used in a simulated grouper aquaculture experiment for 40 days. The FTW removed 1~3 mg/L of dissolved inorganic nitrogen (DIN) throughout the experimental period as well as the following toxic nitrogen species: 88% NO2−-N in the middle stage and 90% TAN (total ammonia nitrogen) in the middle stage. The health of the groupers was promoted and the weight of each grouper was 8% higher than those in the control group in the end. Compared with that of the control group, the carbon sequestration of the aquaculture ecosystem was also increased by S. portulacastrum FTW because more carbon was held in the biomass, including through the growth of the plant mass of the FTW, 109 g C/pond, and a reduction in fishing catch losses, 442 g C/pond. Therefore, S. portulacastrum FTW can serve as a potential technology for improving the water environment quality of feeding ponds and contributing to carbon sequestration in aquaculture systems.

水生植物 Sesuvium portulacastrum 悬浮处理湿地（FTWs）在去除水体中的氮、磷，吸附重金属以及净化水产养殖废水中的有机污染物方面表现出显著效果，从而提升了渔业养殖的生产效率。在本研究中，将 S. portulacastrum FTW 应用于模拟的石斑鱼养殖实验中，持续40天。在整个实验期间，FTW 有效去除水体中 1~3 mg/L 的溶解无机氮（DIN），以及中间阶段的 88% 二氧化氮氮（NO2−-N）和 90% 总氨氮（TAN）。石斑鱼的健康状况得到改善，实验结束时，每尾石斑鱼的体重比对照组高出 8%。与对照组相比，S. portulacastrum FTW 还提高了水产养殖生态系统的碳汇能力，因为生物量中碳的储存量增加，包括 FTW 植物生物量的增长，每池塘109克碳，以及捕捞损失减少，每池塘442克碳。因此，S. portulacastrum FTW 可作为改善养殖池塘水质及促进水产养殖系统碳汇能力的潜在技术。