Lake Erie algal blooms produce many toxic compounds ^{CEFR B1}

A study published in The ISME Journal reports that harmful algal blooms in western Lake Erie produce a wider array of bioactive cyanopeptides than previously recognised. Scientists collected water samples at four NOAA Great Lakes Environmental Research Laboratory stations each month from May through October, 2016–2022. They analysed microbial DNA and detected microbially produced compounds, which allowed them to link specific bacteria to the compounds.

The team found expected toxins such as microcystin from the cyanobacterium Microcystis, plus several other compounds not yet characterised and not tracked by conventional monitoring. Senior author Gregory Dick called microcystin "the tip of the iceberg."

Lead author Lauren Hart described three seasonal phases of bloom chemistry. She also tested interactions: in a study published in Environmental Toxicology, she exposed three human cell lines (lung, liver, kidney) to varying combinations and doses of microcystins and anabaenopeptins. Anabaenopeptins could be as toxic as some microcystin congeners, and mixtures amplified effects. Cell-line results do not directly predict risk to people or animals. Researchers say it is important to characterise these compounds and determine their toxicity. The work involved scientists from the University of Michigan, NOAA, and USGS, and received federal research support.