%0 Journal Article %T An innovative approach for sequential extraction of phosphorus in sediments: Ferrous iron P as an independent P fraction %+ Institute of Hydrobiology [Wuhan] %+ Ecosystèmes, biodiversité, évolution [Rennes] (ECOBIO) %+ Observatoire des Sciences de l'Univers de Rennes (OSUR) %+ Géosciences Rennes (GR) %A Gu, Sen %A Qian, Yiguang %A Li, Qingman %A Pinay, Gilles %A Gruau, Gérard %Z 41373099, National Natural Science Foundation of China %Z 2015LH0044, CPSF-CAS Joint Foundation %< avec comité de lecture %Z PL03609 %@ 0043-1354 %J Water Research %I IWA Publishing/Elsevier %V 103 %P 352-361 %8 2016-10 %D 2016 %R 10.1016/j.watres.2016.07.058 %M 27486948 %K Ferrous iron phosphorus %K Phosphorus fractionation %K Geochemical process %K SEDEX %K Vivianite %Z Sciences of the Universe [physics]/Earth Sciences/GeochemistryJournal articles %X Accurate identification of phosphorus (P) forms is crucially important for understanding the geochemical cycle of P; however, until now the role of ferrous iron P (Fe(II)-P) buried in sediments has been completely ignored in nearly all sequential extraction procedures developed. Using sediment cores sampled from Donghu Lake in Wuhan, China, this study explored a modified version of widely used sequential P extraction method (SEDEX; Ruttenberg, 1992) in which Fe(II)-P was identified as an independent fraction. Based on the high selectivity of the extractant (0.2% 2,2′–bipyridine+0.1 M KCl) and the dissolution equilibrium of P, procedures for extracting Fe(II)-P were optimized using a 1:100 solid:liquid ratio and extraction at 50 ± 1 °C for 24 h. The sedimentary P extracted was divided into five fractions: loosely-bound P, Fe(II)-P, CDB-P, Ca-P and O-P. Fe(II)-P was the predominant fraction in fresh sediments in Donghu Lake, accounting for 15.7–49.9% of TP, with a mean of 31.6%. The mean values of Ca-P, O-P, CDB-P and loosely-bound P were 28.4%, 22.7%, 17.1% and 4.3%, respectively. Combined with component analysis of extracts and recovery experiments of standard reference minerals (vivianite, Fe3(PO4)2·8H2O) in natural sediments, extraction of Fe(II)-P with 0.2% 2,2-bipridine and 0.1 M KCl was robust, with a good recovery rate (88.7–100.6%) and little of the Ca-P dissolved. It is possible to use this innovative SEDEX not only to distinguish the contribution of different P matrices in fresh sediments, but also to investigate the transformation of sedimentary P under different redox conditions. Therefore, greater focus on Fe(II)-P is necessary, because it is a major sink for the geochemical process of sedimentary P. %G English %L insu-01355339 %U https://insu.hal.science/insu-01355339 %~ INSU %~ UNIV-RENNES1 %~ UR2-HB %~ CNRS %~ GR %~ OSUR %~ ECOBIO %~ ECOBIO-RBPE %~ UR1-UFR-SVE %~ UR1-HAL %~ UR1-SDLM %~ UR1-SDLMJONCH %~ UR1-SDV %~ ECOBIO-DYNAMO %~ GR-DIMENV %~ UNIV-RENNES2 %~ TEST-UNIV-RENNES %~ TEST-UR-CSS %~ UNIV-RENNES %~ INRAE %~ UR1-ENV %~ GR-ET