Aerial photos taken on September 26 show blooms of cyanobacteria, or blue-green algae, in Clear Lake at Redbud Park in Clearlake, California, the United States.

Recent test results showed dangerously high levels of Microcystins, a class of potent liver toxin naturally produced in commonly occurring cyanobacteria. Elevated levels of a neurotoxin called Anatoxin-a have also been detected.

Residents and visitors of Clear Lake, California's second-largest freshwater lake, are being urged to use caution when visiting the lake. 

(Images via VCG)

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