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Updated: Mar 7, 2026

Laboratory-determined Phosphorus Flux from Lake Sediments as a Measure of Internal Phosphorus Loading
Published on: March 6, 2014
Release mechanism and kinetic exchange for phosphorus (P) in lake sediment characterized by diffusive gradients in
1State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, PR China; State Environmental Protection Key Laboratory for Lake Pollution Control, Research Center of Lake Eco-Environment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, PR China; Dongtinghu Lake Ecological Observation and Research Station (DEORS), Yueyang, Hunan Province, 41400, PR China; Yunnan Key Laboratory of Pollution Process and Management of Plateau Lake-Watershed, Kunming, Yunnan Province, 650034, PR China.
Abstract:
Diffusive gradients in thin films (DGT) technique has been newly designed for the identification of formation mechanisms of "internal phosphorus (P)-loading" and the numerical simulation of P exchange at DGT/sediment interface in Lake Dianchi. The primary mechanism was Fe-redox controlled P release from Fe-bound P in sediments, which was revealed by CDGT (P and Fe), total P (Fe) and P (Fe) fractions in NH4Cl and BD phases in sediments and their relationships at sites (N-T). The breakdown of algae biomass in the top layer of sediments at sites (O-T) and the coupled P/Fe/sulfur reactions at two depths at site N played a minor role in P release. The "internal P-loading" was calculated to be 19.23ta-1, which was 3.0% of the "entering P-loading". At sites (1-9), DGT induced flux in sediments (DIFS) model for P was used to derive curves (i) the resupply parameter (R) against deployment time and (ii) the dissolved/sorbed concentrations against the distance at DGT/sediment interface, the variation characters of which were controlled by kinetics and sediment-P pool. Sulfide microniches in sediments related to P release were evaluated by computer imaging densitometry (CID). DGT-DIFS-CID should be a reliable method to reveal P mobilization in lake sediments.
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