title: Influence of Spartina alterniflora on the mobility of heavy metals in salt marsh sediments of the Yangtze River Estuary, China.
abstract: Using bio-disturbed sulphide to trace the mobility and transformation of Cu, Pb, Ni and Zn in the sediments of the Spartina alterniflora-dominated salt marsh in the Yangtze River Estuary, measurements were made of the seasonal variations of acid-volatile sulphide (AVS) and of the simultaneously extracted metals (SEM) in the rhizosphere sediments. Microcosm incubation experiments recreating flooding conditions were conducted to evaluate the effect of AVS and other metal binding phases upon the dynamics of Cu, Pb, Ni and Zn in the salt marsh sediments. The results demonstrate that the ratio values of SEM/AVS have a significant seasonal variation in the rhizosphere sediments and that the anoxic conditions in the sediments were likely enhanced by S. alterniflora during the summer and autumn compared with the anoxic conditions resulting from the native species Phragmites australis and Scirpus mariqueter. The incubation experiments suggest that Fe(III) and Mn(IV/III) (hydr)oxides provide important binding sites for heavy metals under oxic conditions, and sulphide provides important binding sites for the Cu and Pb under anoxic conditions. Our observations indicate that the mobility of heavy metals in the salt marsh sediments is strongly influenced by biogeochemical redox processes and that the invasive S. alterniflora may increase the seasonal fluctuation in heavy metal bioavailability in the salt marsh ecosystem.
authors: Department of Geography, School of Resources and Environmental Science, East China Normal University, Shanghai, 200062, People's Republic of China.
authors: Yongjie
authors: Y
authors: Wang
authors: Limin
authors: L
authors: Zhou
authors: Xiangmin
authors: X
authors: Zheng
authors: Peng
authors: P
authors: Qian
authors: Yonghong
authors: Y
authors: Wu
mesh_terms: D001673:Biodegradation, Environmental; D002681:China; D003300:Copper / Q000032:analysis / Q000378:metabolism; D063366:Estuaries; D019015:Geologic Sediments / Q000032:analysis*; D007854:Lead / Q000032:analysis / Q000378:metabolism; D019216:Metals, Heavy / Q000032:analysis* / Q000378:metabolism; D009532:Nickel / Q000032:analysis / Q000378:metabolism; D006109:Poaceae / Q000378:metabolism*; D045483:Rivers; D012621:Seasons; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000378:metabolism; D053833:Wetlands; D015032:Zinc / Q000032:analysis / Q000378:metabolism
chemical_list: D019216:Metals, Heavy; D014874:Water Pollutants, Chemical; D007854:Lead; D003300:Copper; D009532:Nickel; D015032:Zinc