Objectives: 1. To characterize the physiological response of Microcystis spp. to varying [Fe] in laboratory culture, 2. To develop/characterize molecular probes to detect Fe deficiency in Microcystis, 3. To assess toxin production by Microcystis as related to Fe deficiency. Rationale: The western basin of Lake Erie has witnessed recurrent blooms of Microcystis in recent years. Of concern relating to these blooms are issues of aesthetics (rendering the lake unattractive to recreational users) and the safety of potable water resources. This latter issue is related to the well-chronicled production of microcystin-LR, a potent hepatotoxin having both acute and chronic exposure effects. Here we address the role of Fe deficiency as a factor promoting toxin production by Microcystis. The Lake Erie basin is home to approximately 13 million people, many of whom rely on the lake and its watershed for potable water. Determining the factors that influence Microcystis bloom formation, maintenance and toxin production are essential for making informed management decisions that will directly impact water quality and recreational use of the lake.
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