Cyanotoxin Monitoring (Lake Erie)

Produced in Collaboration with NOAA GLERL

How to Read the Data


Field monitoring for HABs occurs on a weekly basis in Lake Erie during HAB season (July – October). The Date Stamp indicates the most recent monitoring date. Year:Month:Day

Legend: Shapes

Different shapes at monitoring sites indicate at which water depth the sample was taken. Squares are scum samples taken from the very top of the water column only when scum is visibly present. Circles are surface samples taken at approximately 0.75 m below the water surface. Triangles are bottom samples taken 1 m above the lake bottom. 

Legend: Color Scale

The color scale on this map follows public health advisory levels used by the Ohio Environmental Protection Agency. Green indicates that the HAB toxin microcystin was detected, but below health advisory levels for drinking water. Yellow indicates that a drinking water advisory is in effect for sensitive populations, because microcystin levels were measured greater than 0.3 ug/L. Orange indicates a drinking water advisory is in effect for everyone, because microcystin levels were greater than 1.6 ug/L . Red indicates that the public should avoid all body contact with the water, because microcystin levels greater than 20 ug/L were detected.

Data Source

This data is produced by the Western Lake Erie Harmful Algal Bloom monitoring program, a joint effort by NOAA Great Lakes Environmental Research Lab (GLERL) and CIGLR with support from the Great Lakes Restoration Initiative. Monitoring data is provided “as is” and have not yet been subjected to quality control or quality assurance procedures. For data with QAQC, please refer to archive data. We work hard to post data from each week’s monitoring soon after collection, but there may be delays.

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About the Research

Visit NOAA GLERL’s website for a deeper look into our research on harmful algal blooms. CIGLR supports the mission and goals of the NOAA Great Lakes Environmental Research Lab, and collaborates with them to develop these next-generation NOAA forecasts. Read the disclaimer.

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Explore other resources on Lake Erie harmful algal blooms.

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Field Monitoring Lead
Casey Godwin
(734) 741-2235

Stakeholder Engagement
Devin Gill
(734) 741-2283

Media Contact
Mary Ogdahl
(734) 741-2276