1. Cyanobacteria and microcystin-LR in a complex lake system representing a range in trophic status: Lake of the Woods, Ontario, Canada.
- Author
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CHEN, HUIRONG, BURKE, JANICE M., MOSINDY, TOM, FEDORAK, PHILLIP M., and PREPAS, ELLIE E.
- Subjects
CYANOBACTERIA ,MICROCYSTINS ,APHANIZOMENON ,FOOD chains ,ANABAENA - Abstract
Euphotic water samples were collected monthly from 16 sites in Lake of the Woods, Ontario, Canada from July to September, 2006 and 2007. Sites represented a range of inorganic nitrogen and phosphorus concentrations and mixing regimes, which was reflected in the spatial variability in phytoplankton biomass and community composition, and cyanobacterial toxin [microcystin-LR (MC-LR)] concentrations. Nutrient concentrations decreased along a south to north transect, concomitant with distance from the main river inlet at the south end of the lake. Filamentous, nitrogen-fixing Aphanizomenon spp. and Anabaena spp. were dominant at most sites: Aphanizomenon was more abundant at southern sites and Anabaena was more abundant at northern sites. MC-LR was detected at all sites at least once (maximum concentration 0.69 μg L−1). However, there was no correlation between MC-LR concentration and the biomass of Anabaena, a documented MC-LR producer. For the pooled data set, total phosphorus and ammonium concentrations were the two parameters most strongly related with MC-LR concentration. Principal components analysis was used to analyze the data set; it indicated that two factors accounted for 81% of the variability among the 12 environmental parameters tested. Factor 1 represented physicochemical characteristics and phytoplankton biomass and Factor 2 represented Anabaena and Woronichinia biomass. [ABSTRACT FROM PUBLISHER]
- Published
- 2009
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