Algal Blooms

Green algae



Algal Blooms 

Throughout the year, Leon County Government monitors our local lakes, ponds and streams and tests our water resources. However, during hot summer months in Leon County, it is not uncommon to notice a pond, lake or stormwater pond turn green due to the growth of algae.

Algae are generally microscopic and can be thought of as simple plant-like organisms. Algae occur naturally all over the world and play an important role in many ecosystems including the foundation for aquatic food chains. There are several different types of algae, including green, brown and red algae. The photosynthetic cyanobacteria, (similar to bacteria and formerly called “blue-green algae”) also make up a major component of the algal community. In the presence of abundant sun and nutrients, algae can proliferate to levels that adversely affect natural resources and humans. This is called an algal bloom.  During an algal bloom, there can be millions of algae cells in one cup of water.

Algal blooms can negatively impact our waterbodies and can wreak havoc on the aquatic ecosystem and surrounding vegetation. An abundance of algae also impairs the clarity and quality of the water body. Another concern with algal blooms is the possibility of toxin production. Certain types of blue-green algae release toxins when the cells die or are ingested. There are about 20 species or groups of freshwater blue-green algae that are toxic or potentially toxic occurring in Florida waters. Depending on the type of toxin produced, health effects can include gastroenteritis, asthma, eye irritation, liver damage, paralysis or death. Leon County surface waters do not provide drinking water to any residents.  More information regarding toxins produced by algae and their effects can be found at the United States Environmental Protection Agency’s website.

What is Causing an Increase in Algae?

Fertilizers, sewage and pet waste entering our water bodies can lead to algal blooms. Reducing or eliminating the amount of fertilizer applied to landscaped areas, following all label directions when applying fertilizers, minimizing any bare or eroded areas, properly maintaining septic systems and properly disposing of pet waste will help prevent algal blooms. Practices that slow the flow of runoff and increase the amount of water absorbed into the ground also help reduce the total nutrient load. The risk of runoff can be lessened by reducing paved surfaces, incorporating mulch and mulch beds into the landscape and amending the soil with compost.

Algal Issues in Leon County

Intermittent algal blooms remain a problem for local lakes. Although algal blooms have not been as prevalent as in previous years, algal blooms in Lakes Munson, Piney Z and Upper Lake Lafayette were observed in 2017. The Center for Disease Control (CDC) provides information on how to reduce exposures and prevent algal illness

What Leon County is Doing to Combat Algal Growth

Leon County's local response to algal blooms have four prongs, which include:

  • A public information campaign on how to reduce personal pollution;
  • The ongoing building and renovating of storm water facilities;
  • Continual monitoring of water quality; and
  • Enforcing storm water facility requirements.

What You Can Do to Help Prevent Algal Growth 

While some harmful algal blooms occur naturally, more recently algal blooms have occurred through negative environmental impacts associated with urban development, mass agriculture and pollution. However, there are important steps that you can take to help prevent algal growths in Leon County and the greater Big Bend Region. 

  • Maintain your septic tank system to prevent wastewater from leaking into nearby water bodies; 
  • Use only the recommended amount (or none at all) of fertilizer to reduce risk of runoff pollution; and 
  • Keep leaves and grass clippings on the lawn-don't blow them into the street and down the drain. If you can't leave your leaves on the lawn they should be bagged up and disposed of. 

Learn more about Algal Blooms

Florida Atlantic University’s Center for Environmental Studies (CES) partnered with the U.S. Geological Survey to develop an educational series of online modules about algae and harmful algal blooms. Visit Understanding Algal Blooms in Florida to learn more about what algae are, where they live and grow, causes of bloom formation, impacts of these blooms, and potential mitigation efforts. This online resource includes short videos, printable handouts, an FAQ section, and a resource guide to learn even more.

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