By Sarah Zeiler
In the summer of 2014, the city of Toledo, Ohio, lost its drinking water for three days. The cause was a harmful algal bloom, often called a HAB, in Lake Erie. This event brought national attention to a problem that many lake users had already noticed.
Harmful algal blooms are not just an issue in Lake Erie. They occur in small lakes, rivers and streams across the Midwest, including in our local waters. Michigan State University Extension helps residents and farmers reduce the risk of harmful algal blooms in waterways by providing research-based recommendations and resources for environmental planning and problem-solving.
What are harmful algal blooms?
A harmful algal bloom happens when algae grow fast and in large amounts. Some types of algae (known as cyanobacteria) produce toxins that can harm people, pets, livestock and wildlife. Blue-green algae has always existed in lakes and rivers. What has changed are the environmental conditions that sometimes allow it to grow out of control.
Why phosphorus matters
One key driver of harmful algal blooms is phosphorus. Phosphorus is a nutrient that plants need to grow, but too much of it in water causes problems. In many lakes, phosphorus is limited, meaning no extra is available. If extra phosphorus enters the water, algae can grow quickly and form blooms.
Experts agree that there is no single cause and no quick fix for harmful algal blooms. Many factors contribute to the problem, including heavy rainstorms, sewer overflows, failing septic systems, urban stormwater, lawn fertilizers, invasive species and agriculture.
Source : msu.edu