“…Macrophytes in salt marshes are widely believed to decrease the rate of tidal flow, cause suspended particulate matter to sediment, enhance the retention rates of nutrients and metals from overlying water, and reduce the import of nutrients and metals to estuarine waters (Cacador, Vale, & Catarino, 2000;Daehler & Strong, 1996;Windham et al, 2003;Windham, 1999). Therefore, salt marshes are often considered efficient sinks for nutrients and metals; they can ameliorate the environmental quality in coastal ecosystem (Romero, Comin, & Garcia, 1999;Coelho, Flindt, & Jensen, 2004;Zhang, Yu, Hutchinson, Xu, Chen, & Gao, 2001). …”