Harmful Algal Blooms (HABs) 101 Resources

Welcome to HABs 101!

“HABs 101” is a series of webinars and other resources hosted by Michigan Sea Grant and partners at state and local agencies. These resources bring the fundamentals of harmful algal bloom science, management, health, and more to audiences around Michigan.

Harmful algal blooms (HABs) are caused by cyanobacteria, tiny organisms that live naturally in the water. Despite being bacteria, they’re often called blue-green algae, because they get energy from the sun like plants. Sometimes cyanobacteria and other types of algae can “bloom,” or multiply quickly enough that their population can be seen by human eyes. Cyanobacteria blooms can make water look green or other unusual colors. 

Sometimes cyanobacteria blooms produce toxins that harm human or animal health, which is why we call them “harmful algal blooms,” or HABs. HABs can grow and fade quickly and may drift around with wind and waves. A visible HAB may linger for several days. Once the water is clear, it’s generally safe to touch. Learn more about HABs here.

NEW RESOURCE (JUNE 2026): If there’s something strange in the water, if you think you have a HAB, or if you’ve reported a HAB, start here: Is there a harmful algal bloom in my lake or pond? (PDF)

UPDATE (JUNE 2026): The State of Michigan has a new digital form for reporting suspected HABs. Click on the “Report it to EGLE” button on the page linked here or call the Environmental Assistance Center at 1-800-662-9278.  

Explore HABs 101 webinars and video clips

“HABs 101” webinars have explored topics from nutrient budgets to invasive Didymo, native plant buffers to public health impacts. Listen to full webinar recordings and find clips covering specific topics.

• HABs 101 webinars and video clips
• Get the highlights from “HABs 101: Lake Stories” through these two recap articles:
  • Lake Stories: Managing nutrients from the inside
  • Lake Stories: Let’s talk to the neighbors

Resources for a deeper dive

• Is it a HAB? 
  • Michigan Harmful Algal Bloom Story Map (webpage; EGLE, MDHHS)
  • EGLE Classroom – Identifying Harmful Algal Blooms/Cyanobacteria (YouTube video; EGLE)
  • Michigan Harmful Algal Bloom Picture Guide (PDF; EGLE, MDHHS)
• Reporting HABs in Michigan
  • Submit this digital form or call the Environmental Assistance Center at 1-800-662-9278.
  • View HABs reports: Michigan HAB reports map (ArcGIS map; MDHHS)
• Harmful Algal Blooms: FAQs (PDF; MDHHS, MDARD, EGLE)
• Harmful Algal Blooms: Pets and livestock (PDF; MDARD)
• Harmful Algal Blooms: Prevention and Treatment for Landowners (PDF; North Central Region Water Network Algal Bloom Action Team)
• Preserving Our Waters: An Overview of USGS Harmful Algal Blooms Science and Monitoring in the Great Lakes (Storymap; USGS)

Webpages/Sites

• Michigan HABs webpage (webpage; EGLE)
• Michigan Harmful Algal Blooms StoryMap (ArcGIS StoryMap, EGLE)
• MI residents soil testing (how much phosphorus and nitrogen is in the soil, is fertilizer needed?)

Fact Sheets 

Basics

• Harmful Algal Blooms – What You Should Know (PDF, North Central Region Water Network Algal Bloom Action Team)
• Who Does What? A Guide to Agencies’ Roles in HABs (PDF, Great Lakes HABs Collaborative)
• 2021 MI HABs summary (PDF, MDHHS)
• 2022 MI HABs summary (PDF, MDHHS)

Human Health

• Chronic Long-Term Health Effects of HAB Toxins (PDF, Great Lakes HABs Collaborative)
• Health Effects Associated with Exposure to HAB Toxins through Aerosolization (PDF, Great Lakes HABs Collaborative)
• Human Health Recreational Ambient Water Quality Criteria/Swimming Advisories for Microcystins and Cylindrospermopsin (PDF, EPA)

Pets and Livestock

• Harmful Algal Blooms: Veterinarians (PDF; MDARD)
• Harmful Algal Blooms and their Health-Related Effects on Animals (PDF, North Central Region Water Network Algal Bloom Action Team)

Science of HABs

• Great Lakes Harmful Algal Blooms: Current Knowledge Gaps (PDF, Great Lakes HABs Collaborative)
• How Does Nitrogen Affect Harmful Algal Blooms? (PDF, Great Lakes HABs Collaborative)
• Phosphorus (P) and HABs: Sources of P from the Maumee River (PDF, Great Lakes HABs Collaborative)
• NOAA GLERL HABs research (PDF, NOAA GLERL) 
• CIGLR HABs Hypoxia fact sheet (PDF, CIGLR) 
• CIGLR HABs research bookmark (PDF, CIGLR) 

Webinars

• Harmful Algal Blooms in Michigan’s Recreational Waters webinar (YouTube, EGLE)
• North Central Region Water Network HABs webinars and virtual research symposium (YouTube channel, NCRWN)
• Great Lakes HABs Collaborative webinars (webpage, Great Lakes HABs Collaborative)
• EPA Research Harmful Algal Blooms, Hypoxia and Nutrients Bimonthly webinar series (webpage, EPA)

Webpages/Sites for a deeper dive

• What are HABs? (webpage, Ohio Sea Grant)
• Algal Bloom Action Team / Resources (webpage; North Central Region Water Network)
• ITRC’s Strategies for Preventing and Managing Cyanobacterial Blooms 
• ITRC’s Strategies for Preventing and Managing Benthic Cyanobacterial Blooms
• National: CDC resources (webpage, CDC)
• National: EPA resources (webpage, EPA)
• HABs online resources list (PDF, CDC)
• MI Natural Shoreline Partnership (webpage, Natural Shoreline Partnership)
• Private drinking water well testing resources: 
  • EGLE well testing kit process (webpage, EGLE)
  • More well-related resources (webpage, MDHHS)

Other Tools

• Great Lakes HABs Collaborative Research Mapper (ArcGIS map, Great Lakes HABs Collaborative) 
• MI EnviroImpact Tool (decision support tool for short-term manure application planning that shows daily runoff risk across Michigan, MSU Extension and MISG)
• Michigan HABs Risk Dashboard (MSU Extension/MISG articles explaining how to use tool):
  • Online dashboard explores HABs and community health
  • Online tool identifies areas where people in Michigan are at greatest risk from harmful algal blooms (HABs)

The resources on this page were compiled by: Michigan Sea Grant, MSU Extension, Michigan Department of Health and Human Services and other partners around the state.