SS3.14 An Interdisciplinary Journey Towards Integrated Aquatic Sciences: Homage to Jacob Kalff
Date: Thursday, June 13, 2002
Time: 11:15:00 AM
Location: Saanich
 
Giani, A, , Universidade Federal de Minas Gerais, Belo Horizonte, BRAZIL, agiani@icb.ufmg.br
BirdDF, Universite du Quebec a Montreal, Montreal, CANADA, bird.david@uqam.ca
Prairie, Y, T, UQAM, Montreal, CANADA, prairie.yves@uqam.ca
 
MICROCYSTIN LEVELS IN A SERIES OF ST. LAWRENCE LOWLAND LAKES: CAUSES AND CONSEQUENCES
image
Besides being a recreational nuisance, bloom-forming cyanobacteria can contain significant levels of neurotoxins and hepatotoxins that can be tumour promoters. These blooms vary greatly in toxicity, for reasons that are unknown. Because of health concerns, the appearance of cyanobacterial blooms in a formerly oligotrophic lake in Quebec, on which a fish farm had recently been established, had negative legal and economic consequences for everyone involved: the farmer, the cottage owners and the government. To determine the threat to public health of the cyanobacterial problem across a range of lakes in southern Quebec, we measured blue-green abundance and toxicity, as well as physicochemical variables implicated in production of the most common hepatotoxin, microcystin. All sample lakes but one had relatively weak levels of toxicity (< 100 ng microcystin/L). Microcystin content of the eutrophic lake Tomcod was very high at 2.2 mg total microcystins per L, due to abundant cyanobacteria and to high levels of microcystin per cell. We used literature data to try to find an empirical pattern to explain the variability in cell-specific toxicity among lakes.