Detection and quantification of Microcystis spp. and microcystin-LR in Western Lake Erie during the summer of 2007

摘要

Microcystis spp. blooms have occurred annually in western Lake Erie since about 1995.nMicrocystis produce a group of toxins known as microcystins which can be harmful to livestocknand to humans. In this study, surface water samples were collected from six sites during sixnsampling events from July to October in 2007. In situ environmental data (e.g. pH, temperature)nand laboratory analyses (e.g. nutrients) were carried out to characterize the six sites. ThenMicrocystis spp. density ranged from 102nto 107ncells/ml. Microcystin-LR concentration of 20 of alln36 samples were below the detection limit (0.15–5 ppb), while the microcystin-LR concentrationnin the 16 remaining samples ranged from 0.5 to 3 £ 103nmg per gram dry weight. The aim of thisnresearch was to investigate the relationships between sampling location, environmentalnparameters, Microcystis spp. concentration, and microcystin-LR concentration. The resultsnsuggest that temperature, nutrient concentration, turbidity, and wind speed and directionn( P , 0.05) are factors which affected Microcystis spp. density. Sampling site 8M, located 13mnfrom the Maumee River, provided an advantage for Microcystis spp. growth, presumably due tonintermediate water depth (5.5m) combined with impact from the river. No relationship was foundnbetween Microcystis spp. density and microcystin-LR concentration. Temperature, nutrientnconcentration and DO ( P , 0.05) were associated with the production of microcystin-LR.