Lake Ivanhoe has been closed due to the presence of microcystins, detected by the City of Orlando and the Florida Department of Evironmental Protection.
The City will continue to test Lake Ivanhoe until the levels of toxins have dropped to acceptable levels. Until that time, all water contact activities must cease until further notice.
For reference, cyanobacteria/blue-green algae are always present in the water, however, not all bacteria have the ability to produce toxins. Toxicity is hard to predict because a single species of algae can have toxic and non-toxic strains. This instance is believed to have occurred due to the water in the lake “flipping.” During the colder months, the warm surface water begins to cool. As water cools, it will become more dense, causing it to sink. This dense water forces the water of the bottom layer to rise, turning the layers over. The bottom layer tends to be very nutrient rich, then is exposed to sunlight at the surface level and causes an algae bloom to occur.