title: Outdoor experimental ponds (mesocosms) designed for long-term ecotoxicological studies in aquatic environment.
abstract: Outdoor artificial ponds (mesocosms) of 12 m3 were designed for long-term ecotoxicological studies. Sediment, macrophytes (Typha angustifolia and Elodea canadensis), and free and caged freshwater snails [Lymnaea palustris (Müller)] and wood lice (Asellus aquaticus L.) were collected in nearby natural ecosystems and introduced in the mesocosms. Sixty goldfish (Carassius auratus L.) were caged in each pond. Introduced species developed and reproduced in every mesocosm. Animal species (mainly insects and amphibians) spontaneously colonized the ponds, developed, and reproduced. The resulting communities qualitatively resemble those living in natural lentic systems in the surrounding area. Homogenity in physical and chemical conditions and in abundance of phytoplanktonic, periphytic, and macroinvertebrate communities between the different mesocosms was assessed during the stabilization period (8 months). Except for periphyton biomass, no divergent evolution was observed between the ponds. Mesocosm water was slightly eutrophic, alkaline (mean pH: 8.47 +/- 0.09), and moderately hard and mineralized. The homogenous and realistic environmental conditions and high ecological representativity of the outdoor experimental ponds were suitable for extensive ecotoxicological studies. Considerations on the choice and origin of introduced species and on possible interactive effects of the transfer of organisms from natural environments, maintainance conditions, and pollutant exposure are discussed.
authors.affiliation: Laboratoire d'Ecologie et de Zoologie, Université de Paris-Sud, Orsay Cedex, F-91405, France.
authors.forename: T
authors.initials: T
authors.lastname: Caquet
authors.forename: L
authors.initials: L
authors.lastname: Lagadic
authors.forename: O
authors.initials: O
authors.lastname: Jonot
authors.forename: W
authors.initials: W
authors.lastname: Baturo
authors.forename: M
authors.initials: M
authors.lastname: Kilanda
authors.forename: P
authors.initials: P
authors.lastname: Simon
authors.forename: S
authors.initials: S
authors.lastname: Le Bras
authors.forename: M
authors.initials: M
authors.lastname: Echaubard
authors.forename: F
authors.initials: F
authors.lastname: Ramade
mesh_terms: D000818:Animals; D018533:Biomass; D004553:Electric Conductivity; D005618:Fresh Water; D006054:Goldfish; D017408:Guidelines as Topic; D006863:Hydrogen-Ion Concentration; D008195:Lymnaea; D009566:Nitrates / Q000633:toxicity*; D010710:Phosphates / Q000633:toxicity*; D008003:Phthiraptera; D010839:Phytoplankton / Q000187:drug effects; D012098:Reproduction / Q000187:drug effects; D013045:Species Specificity; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D009566:Nitrates; D010710:Phosphates; D014874:Water Pollutants, Chemical; C006568:ammonium nitrate