Sarnelle O, White JD, Horst GP, Hamilton SK
Microcystis, cyanobacteria, phosphorus, Dreissena polymorpha, eutrophication, Harmful algal bloom, HAB, grazing, Zebra mussel, blue-green-algae, low-nutrient lakes, hudson river, relative biomass, filtration-rate, great-lakes, new-york, phytoplankton, dominance, invasion, freshwater, California, USA, 25m3
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 similar to 10 mu g L-1), and a significantly negative effect at high P (simulating a TP of similar to 40 mu g 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. (C) 2012 Elsevier Ltd. All rights reserved.