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Nitrogen forms influence microcystin concentration and composition via changes in cyanobacterial community structure
Marie-Eve Monchamp1, Frances R Pick2, Beatrix E Beisner3
1Groupe de Recherche Interuniversitaire en Limnologie et en Environnement Aquatique (GRIL), Département de Sciences Biologiques, Université de Montréal, Montréal, Québec, Canada.
Plos One
|January 16, 2014
Summary
Nitrogen forms impact freshwater cyanobacterial blooms and toxicity. Microcystis biomass best predicts microcystin levels, while environmental factors shape community structure and bloom toxicity.
Area of Science:
- Environmental science
- Aquatic ecology
- Toxicology
Background:
- Eutrophication of freshwater lakes globally leads to harmful cyanobacterial blooms.
- While phosphorus is a key driver of biomass, nitrogen species influence bloom toxicity.
- Understanding nitrogen's role is crucial for managing toxic cyanobacterial blooms.
Purpose of the Study:
- To investigate how nitrogen species and environmental factors affect cyanobacterial community structure, microcystin (MC) concentrations, and MC congener composition in eutrophic lakes.
- To identify specific MC congeners and their association with different cyanobacteria species.
- To determine the best predictors of MC concentrations and overall bloom toxicity.
Main Methods:
- Study conducted in three eutrophic lakes prone to cyanobacterial blooms.
- Analysis of nitrogen species (total nitrogen, dissolved organic nitrogen, ammonium), water temperature, and other environmental factors.
- Redundancy analysis (RDA) to link cyanobacterial community structure, MC concentrations, and congener composition to environmental variables.
Main Results:
- Nitrogen forms influenced cyanobacterial community structure, impacting MC concentrations and composition.
- Microcystis spp. biomass was the strongest predictor of total MC concentrations.
- Specific MC congeners were associated with particular species (e.g., Microcystis aeruginosa with MC-RR, M. wesenbergii with MC-LA).
Conclusions:
- Environmental factors and nitrogen availability shape cyanobacterial communities, affecting bloom toxicity.
- Microcystis biomass is a key indicator for MC concentrations.
- Associations between MC congeners and specific species suggest species-specific toxin production, even in species not typically known for MC production.
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