Algae blooms on Lake Kegonsa in 2010.
Algae blooms on Lake Kegonsa in 2010. Wisconsin Department of Health Services
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Project: Murky Waters

The Capital Times and Wisconsin Center for Investigative Journalism collaborated on this four-part series to examine threats to the quality of the Madison area’s spectacular lakes, and ambitious new efforts that seek to improve them. Researchers around the world are watching our lakes in hopes of adapting these lessons to troubled bodies of water in other areas.
Murky Waters project page: Stories, data visualizations, photos.

How to spot them

From the U.S. Centers for Disease Control: Look for “a foam, scum, or mats on the surface of fresh water lakes and ponds. The blooms can be blue, bright green, brown, or red and may look like paint floating on the water. Some blooms may not affect the appearance of the water. As algae in a cyanobacterial bloom die, the water may smell bad.”

If you spot them

  • Call the authorities. Kirsti Sorsa at Madison and Dane County Public Health: 243-0356. Around the state: Check the DNR’s frequently asked questions about blue-green algae for relevant phone numbers.
  • If it’s a swimming area, collect a water sample. “It doesn’t have to be sterile,” Sorsa said.
  • Try a different beach. Water quality can vary a lot around a lake. “People think that if one beach is closed, the whole lake is in bad shape,” Sorsa said. “There are lots of good places to swim.”

Algae and illness

Cyanobacteria don’t always produce the toxins that make people sick. The toxins vary in their toxicity and what they damage — some are neurotoxins that affect the central nervous system, while others damage the liver. Symptoms may not show up immediately, said Sorsa.
Signs of illness in people: Respiratory symptoms include sore throat, cough, wheezing, trouble breathing and irritated eyes. Skin may become itchy, red or blistered, or hives may appear. Other symptoms can include agitation, headache, abdominal pain, diarrhea or vomiting, according to the Wisconsin Department of Health Services.
Signs of illness in pets: Lethargy or weakness, difficulty breathing, diarrhea, seizures or vomiting. Pets and algae: fact sheet from DHS.
Where to report potential illness: Online, use the DHS’s Algae-Related Illness Report Form. Or call DHS at 608-266-1120.

This series, Murky Waters, was produced collaboratively by The Capital Times and Wisconsin Center for Investigative Journalism. It is part of Water Watch Wisconsin, a project supported by The Joyce Foundation that is examining water quality and supply issues statewide. Center reporter Ron Seely contributed to this report.

The nonprofit Wisconsin Center for Investigative Journalism (

) collaborates with Wisconsin Public Radio, Wisconsin Public Television, other news media and the UW-Madison School of Journalism and Mass Communication.

All works created, published, posted or disseminated by the Center do not necessarily reflect the views or opinions of UW-Madison or any of its affiliates.

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Kate Golden, multimedia director and reporter, specializes in environmental stories and data visualizations.