The study compared how well two types of plants, Phragmites australis and Typha angustifolia, can handle salty and alkaline conditions in a coastal estuary area. They found that Phragmites australis can handle higher salt levels and remove more ammonia nitrogen, while Typha angustifolia can remove more nitrate nitrogen and phosphorus due to its larger size. Both plants can be used to clean up nitrogen and phosphorus in high salt-alkaline water.