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Phosphorus Fluxes at the Sediment-Water Interface in a Temperate Region Agricultural Catchment.

Su, Jingjun; Bochove, Eric; Auclair, Jean-Christian; Thériault, Georges; Hu, Chengxiao; Li, Xuyong (2014). Phosphorus Fluxes at the Sediment-Water Interface in a Temperate Region Agricultural Catchment. Water, Air, & Soil Pollution , vol. 225 , nº 1. Article number 1739. DOI: 10.1007/s11270-013-1739-2.

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Résumé

Phosphorus (P) release and flux at sediment-water interface was hypothesized to vary with studied catchment branches due to differences in water chemistry of recharging groundwater. Stream water, seepage water, groundwater, and resurgence groundwater were collected, and their dissolved reactive P (DRP) concentrations and related water chemistry variables (pH, dissolved oxygen, cations, and anions) were measured to identify P sources in seepage water and resurgence groundwater and to look into their impacts on stream water DRP. Results showed that the groundwater-carried P concentrations were negligible, and, thus, not a direct source of DRP to stream water. However, the upwelling groundwater could contribute to stream water DRP by dissolving calcite-bound P in top sediments of branch 15. The seepage experiment indicated that in branch14, sediment release of reducible P was minimal. Furthermore, the presence of impermeable clay layer over the streambed of branch 14 prevented the transport of water and nutrients from beneath sediments to stream water, further reducing the P flux across the sediment-water interface. This study revealed that in branch 14, the recharge of anoxic groundwater did not significantly influence stream water P, due directly to its low P concentration, or indirectly to the lack of reducible P and the poor hydrological connectivity in bottom sediments. These results showed that differences between P soluble concentrations in small catchment streams can be explained by physicochemical processes at the sediment-water interface. More investigation is needed to assess whole catchment P dynamics.

Type de document: Article
Mots-clés libres: phosphorus; source; groundwater; sediment-water interface
Centre: Centre Eau Terre Environnement
Date de dépôt: 13 déc. 2016 20:37
Dernière modification: 29 août 2017 18:51
URI: http://espace.inrs.ca/id/eprint/3520

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