title: Long-term efficiency of lake restoration by chemical phosphorus precipitation: Scenario analysis with a phosphorus balance model.
abstract: An artificial increase of phosphorus (P) retention in lakes with a long residence time and/or a large mobile sediment P pool by adding P binding chemicals can drastically shorten the time these lakes require to reach water quality targets. Suitable tools to optimize timing and extent of external and internal measures are lacking. The one-box model, a mass balance tool for predicting the P trend in the water under different management options was applied to highly eutrophic Lake Arendsee (a = 5.14 km(2), zmax = 49 m), Germany. Mass developments of blue green algae and increasing hypolimnetic oxygen deficiencies are urgent reasons for restoring Lake Arendsee. Detailed studies of P cycling and scenario analyses with the one-box model led to the following conclusions: i) immediate improvement of the trophic state is only possible by in-lake P inactivation because of the long water residence time (56 years); ii) a gradual external P load reduction, even if the effect is delayed, will assure the sustainability of the scheduled Al application beyond one decade; iii) a twofold precipitation reduces the risk of failure compared to a singular application with an overdose related to the relevant internal P pools.
authors.affiliation: Leibniz-Institute of Freshwater Ecology and Inland Fisheries Berlin, Müggelseedamm 301, D-12587 Berlin, Germany. Electronic address: hupfer@igb-berlin.de.
authors.forename: Michael
authors.initials: M
authors.lastname: Hupfer
authors.affiliation: University of Southern Denmark Odense, Institute of Biology, Campusvej 55, DK-5230 Odense M, Denmark.
authors.forename: Kasper
authors.initials: K
authors.lastname: Reitzel
authors.affiliation: Leibniz-Institute of Freshwater Ecology and Inland Fisheries Berlin, Müggelseedamm 301, D-12587 Berlin, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Kleeberg
authors.affiliation: Leibniz-Institute of Freshwater Ecology and Inland Fisheries Berlin, Müggelseedamm 301, D-12587 Berlin, Germany.
authors.forename: Jörg
authors.initials: J
authors.lastname: Lewandowski
mesh_terms: D011232:Chemical Precipitation; D005068:Eutrophication; D019015:Geologic Sediments; D060106:Lakes; D010758:Phosphorus; D014874:Water Pollutants, Chemical
chemical_list: D014874:Water Pollutants, Chemical; D010758:Phosphorus
keywords: Eutrophication; Lake restoration; One-box model; Phosphorus binding chemicals; Phosphorus retention; Sediment