title: Editorial - A critical perspective on geo-engineering for eutrophication management in lakes.
abstract: Eutrophication is the primary worldwide water quality issue. Reducing excessive external nutrient loading is the most straightforward action in mitigating eutrophication, but lakes, ponds and reservoirs often show little, if any, signs of recovery in the years following external load reduction. This is due to internal cycling of phosphorus (P). Geo-engineering, which we can here define as activities intervening with biogeochemical cycles to control eutrophication in inland waters, represents a promising approach, under appropriate conditions, to reduce P release from bed sediments and cyanobacteria accumulation in surface waters, thereby speeding up recovery. In this overview, we draw on evidence from this special issue Geoengineering in Lakes, and on supporting literature to provide a critical perspective on the approach. We demonstrate that many of the strong P sorbents in the literature will not be applicable in the field because of costs and other constraints. Aluminium and lanthanum modified compounds are among the most effective compounds for targeting P. Flocculants and ballast compounds can be used to sink cyanobacteria, in the short term. We emphasize that the first step in managing eutrophication is a system analysis that will reveal the main water and P flows and the biological structure of the waterbody. These site specific traits can be significant confounding factors dictating successful eutrophication management. Geo-engineering techniques, considered collectively, as part of a tool kit, may ensure successful management of eutrophication through a range of target effects. In addition, novel developments in modified zeolites offer simultaneous P and nitrogen control. To facilitate research and reduce the delay from concept to market a multi-national centre of excellence is required.
authors.affiliation: Aquatic Ecology & Water Quality Management Group, Department of Environmental Sciences, Wageningen University, P.O. Box 47, 6700 AA Wageningen, The Netherlands; Department of Aquatic Ecology, Netherlands Institute of Ecology (NIOO-KNAW), P.O. Box 50, 6700 AB, Wageningen, The Netherlands. Electronic address: miquel.lurling@wur.nl.
authors.forename: Miquel
authors.initials: M
authors.lastname: Lürling
authors.affiliation: Lake Ecosystems Group, Centre for Ecology & Hydrology, Bailrigg, Lancaster LA1 4AP, UK.
authors.forename: Eleanor
authors.initials: E
authors.lastname: Mackay
authors.affiliation: Department of Biology, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark.
authors.forename: Kasper
authors.initials: K
authors.lastname: Reitzel
authors.affiliation: Freshwater Ecology Group, Centre for Ecology & Hydrology, Penicuik, Midlothian EH26 0QB, UK.
authors.forename: Bryan M
authors.initials: BM
authors.lastname: Spears
mesh_terms: D000458:Cyanobacteria; D005068:Eutrophication; D060106:Lakes / Q000737:chemistry*; D009584:Nitrogen; D010758:Phosphorus
chemical_list: D010758:Phosphorus; D009584:Nitrogen
keywords: Eutrophication management; Geo-engineering in lakes; Lake rehabilitation; Phosphorus sorbent; System analysis