title: Kinetics of phosphorus release from sediments and its relationship with iron speciation influenced by the mussel (Corbicula fluminea) bioturbation.
abstract: The effects of bivalve (Corbicula fluminea) bioturbation on the lability of phosphorus (P) in sediments were investigated. The high-resolution dialysis (HR-Peeper) and diffusive gradients in thin films (DGT) techniques were employed to obtain soluble and labile P/Fe profiles at a vertical resolution of 2 and 1mm, respectively. The bivalve bioturbation increased the concentrations of soluble reactive P (SRP) in pore water and DGT-labile P up to 116% and 833% of the control within the sediment depths from the sediment water interface (SWI) to -64 mm and -44 mm, respectively. The sediments with bioturbation had a smaller distribution coefficient than the control (1964 vs. 3010 cm(3) g(-1)), reflecting a weaker ability in retaining P. Meanwhile, the sediments with bioturbation had a greater ratio of the concentration of DGT-labile P to that of SRP (0.20 vs. 0.03), demonstrating a stronger ability to resupply pore water SRP by the sediment solids when they are affected by the bioturbation. The DGT-induced fluxes in sediments (DIFS) modeling further showed a much shorter response time (277.9 vs. 18,670 s) and a much higher rate (0.192 vs. 0.002 day(-1)) of the solids in release of P with the bioturbation. Correspondingly, the flux of P to the overlying water from the bioturbation treatment increased up to 157% of the control. The bivalve bioturbation significantly increased the concentrations of soluble Fe(II) and DGT-labile Fe up to 84% and 334% of the control from the SWI to -46 mm, respectively. The SRP and DGT-labile P were highly correlated with respective soluble and DGT-labile Fe. It was concluded that the release of P from the sediments with bioturbation to the pore water and the overlying water was promoted by the reductive dissolution of easily reducible Fe(oxyhydr)oxides due to the depletion of oxygen in the top sediments from bivalve respiration.
authors.affiliation: College of Hydrology and Water Resources, Hohai University, Nanjing 210098, China; State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China.
authors.forename: Musong
authors.initials: M
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China. Electronic address: smding@niglas.ac.cn.
authors.forename: Shiming
authors.initials: S
authors.lastname: Ding
authors.affiliation: College of Hydrology and Water Resources, Hohai University, Nanjing 210098, China. Electronic address: lingliu@hhu.edu.cn.
authors.forename: Ling
authors.initials: L
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China.
authors.forename: Di
authors.initials: D
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China.
authors.forename: Mengdan
authors.initials: M
authors.lastname: Gong
authors.affiliation: College of Environmental Science and Engineering, Anhui Normal University, Wuhu 241000, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Tang
authors.affiliation: GIS Centre, Ryan Institute and School of Geography and Archaeology, National University of Ireland, Galway, Ireland.
authors.forename: Chaosheng
authors.initials: C
authors.lastname: Zhang
mesh_terms: D000818:Animals; D049874:Corbicula / Q000502:physiology*; D004784:Environmental Monitoring; D019015:Geologic Sediments / Q000737:chemistry*; D007501:Iron / Q000737:chemistry; D007700:Kinetics; D010758:Phosphorus / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D014874:Water Pollutants, Chemical; D010758:Phosphorus; D007501:Iron
keywords: Bioturbation; Diffusive gradients in thin films; High resolution; Phosphorus; Sediment