LAUSR

As increases in anthropogenic eutrophication and climate change contribute to more severe and frequent cyanobacterial harmful algal blooms in freshwater ecosystems worldwide, understanding the effects and consequences cyanobacterial blooms have on aquatic organisms is crucial. Microcystis aeruginosa is one of the most common cyanobacteria taxa found in cyanobacterial blooms, producing a number of toxins including Microcystins. This study examined the effects of Microcystis aeruginosa on aquatic benthic macroinvertebrates, specifically the pollution intolerant taxa Ephemeroptera, the pollution moderately intolerant taxa Zygoptera, and the pollution tolerant taxa Chironomidae. In a controlled lab environment, macroinvertebrates were exposed to approximately 100,000 cells/ml of Microcystis aeruginosa. The survival percentage was lower for macroinvertebrates exposed to Microcystis aeruginosa in all three tolerance groups (p < 0.001) while corresponding with the pollution tolerance levels of the species. Mayflies had a survival percentage of 38% in the treatment groups compared to a 98% survival percentage for control groups. Damselflies had a 43% survival percentage in the treatment groups compared to a 98% survival percentage in the control groups. Midges had a 72% survival percentage in the treatment groups compared to a 100% survival percentage in the control groups. These findings support the notion that cyanobacterial blooms have deleterious effects on freshwater ecosystems and can affect aquatic food webs.