title: Phosphorus addition reverses the positive effect of zebra mussels (Dreissena polymorpha) on the toxic cyanobacterium, Microcystis aeruginosa.
abstract: We tested the hypothesis that zebra mussels (Dreissena polymorpha) have positive effects on the toxin-producing cyanobacterium, Microcystis aeruginosa, at low phosphorus (P) concentrations, but negative effects on M. aeruginosa at high P, with a large-scale enclosure experiment in an oligotrophic lake. After three weeks, mussels had a significantly positive effect on M. aeruginosa at ambient P (total phosphorus, TP ∼10 μg L⁻¹), and a significantly negative effect at high P (simulating a TP of ∼40 μg L⁻¹ in lakes). Positive and negative effects were strong and very similar in magnitude. Thus, we were able to ameliorate a negative effect of Dreissena invasion on water quality (i.e., promotion of Microcystis) by adding P to water from an oligotrophic lake. Our results are congruent with many field observations of Microcystis response to Dreissena invasion across ecosystems of varying P availability.
authors.affiliation: Department of Fisheries and Wildlife, Michigan State University, East Lansing, MI 48824, USA. sarnelle@msu.edu
authors.forename: Orlando
authors.initials: O
authors.lastname: Sarnelle
authors.forename: Jeffrey D
authors.initials: JD
authors.lastname: White
authors.forename: Geoffrey P
authors.initials: GP
authors.lastname: Horst
authors.forename: Stephen K
authors.initials: SK
authors.lastname: Hamilton
mesh_terms: D000818:Animals; D001682:Biological Availability; D000458:Cyanobacteria / Q000187:drug effects; D049875:Dreissena / Q000502:physiology*; D017753:Ecosystem; D005068:Eutrophication; D060106:Lakes; D046931:Microcystis / Q000187:drug effects* / Q000502:physiology*; D010758:Phosphorus / Q000493:pharmacokinetics / Q000494:pharmacology*
chemical_list: D010758:Phosphorus