title: A microcosm experiment to determine the consequences of magnetic microparticles application on water quality and sediment phosphorus pools.
abstract: This study used microcosms to evaluate the effects of adding iron (Fe) magnetic microparticles (MPs) on water quality, focusing on P concentrations in the water column and sediment. Two treatments were considered for a constant 85:1 MP:PMobilemolar ratio: T-W, applying MPs on the surface water layer; and T-S, applying MPs on the sediment. MP addition reduced P concentrations in lake water and sediment, with both treatments producing a mean reduction of 68±6% in dissolved inorganic P concentration (DIP) over a 70-day oxic period and reductions of 80±8% (T-W) and 80±4% (T-S) over a 5-day anoxic period. MPs also decreased reactive silicate (Si) concentrations by around 50% in both periods, but dissolved organic carbon (DOC) was reduced by only 15% at 24h after MP addition. Despite the marked decrease in DIP concentration due to MP addition, there was no reduction in chlorophyll a (Chla), because post-treatment total P concentrations (>200μgL-1vs. >700μgL-1before treatments) remained higher than required for changes in the biological community (0.05-0.1mgL-1). With T-S treatment, there was a reduction of 15% in P bound to Al oxides, clay minerals, and humic substances (P→NaOH) and of 12% in labile organic P (Org-PLabile) versus controls. P bound to humic substances (P→NaOH, Humic) was reduced by 11-22% in both treatments. Finally, T-W rather than T-S treatments are recommended for future whole-lake applications to achieve more effective P removal from water and sediment and a higher percentage MP recovery.
authors.affiliation: Departamento de Ecología, Facultad de Ciencias, Universidad de Granada, 18071, Spain; Instituto del Agua, Universidad de Granada, 18071, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Funes
authors.affiliation: Departamento de Ecología, Facultad de Ciencias, Universidad de Granada, 18071, Spain; Instituto del Agua, Universidad de Granada, 18071, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Del Arco
authors.affiliation: Departamento de Ecología, Facultad de Ciencias, Universidad de Granada, 18071, Spain; Instituto del Agua, Universidad de Granada, 18071, Spain.
authors.forename: I
authors.initials: I
authors.lastname: Álvarez-Manzaneda
authors.affiliation: Departamento de FísicaAplicada, Facultad de Ciencias, Universidad de Granada, 18071, Spain.
authors.forename: J
authors.initials: J
authors.lastname: de Vicente
authors.affiliation: Departamento de Ecología, Facultad de Ciencias, Universidad de Granada, 18071, Spain; Instituto del Agua, Universidad de Granada, 18071, Spain. Electronic address: ivicente@ugr.es.
authors.forename: I
authors.initials: I
authors.lastname: de Vicente
keywords: Eutrophication; Lake restoration; Magnetic microparticles; Microcosms; Phosphorus