Is the St. Johns River in Danger? Don’t Feed the Algae

Drayton Island

st. johns riverkeeper 

Algae bloom season is already upon our St. Johns River. Since mid-April, St. Johns Riverkeeper has received dozens of reports from Lake George and Palatka and all the way to Jacksonville. Our team is saddened by the images flooding our communication channels of the green muck coating our River. This early start could potentially be a sign of worse blooms to come as sunny days, water temperatures, and rains continue to rise.

Nutrients? Aren’t those good for the River?

Algae blooms are visible symptoms of sickness and too much nutrient pollution in our waterways. Nutrients, like nitrogen and phosphorus, are naturally occurring in our environment; however, in great excess, they can undermine the ecological integrity of our waterways by depleting oxygen from the water, which negatively impacts plankton and causes fish die-offs, and hurting submerged grasses by blocking adequate sunlight. The River’s entire food web becomes severely harmed.

St. Johns Riverkeeper, Algae in the St. Johns,
Lake George

Impact on Us

Algal blooms can be highly toxic and can make us and our pets sick. Exposure to toxic algae can cause short term respiratory and skin issues as well as long term damage to the nerves and liver. If citizens spot what looks like bright green paint-like, scum on the surface of the water, they should steer clear. Do not recreate, boat, swim, or fish near an algae bloom.  

St. Johns Riverkeeper, Algae in the St. Johns

So, where are all the excess nutrients coming from?

Some of the major sources of nutrient pollution in the St. Johns River:

  • The application of sewage sludge (also known as biosolids) on agricultural lands surrounding our River’s Headwaters at Blue Cypress Lake.
  • Fertilizer runoff from agricultural and residential lands.
  • Malfunctioning septic tanks can leak sewage into our River and not all nutrients are absorbed or filtered in properly functioning septic tanks.
  • Industrial wastewater discharge.
St. Johns Riverkeeper, Algae in the St. Johns
Buffalo Bluff

Advocacy and Outreach

From our Headwaters to our River’s mouth, nearly 310 miles away, St. Johns Riverkeeper is working at the state and local level to influence policymakers to provide greater nutrient protections for our River as well as educating the citizens on ways they can help us save the St. Johns from home.

  • During the 2019 Legislative Session, we took a bus-load of citizens from across our watershed to Florida’s Capitol to connect with their decision makers and advocate for cleaner water.
  • We collaborated with environmental and business partners to launch our annual River Friendly Yard Award Contest, which raises awareness on River Friendly principles and celebrates homeowners who try to make a difference for the River in their yards.
  • We’ll continue to educate citizens by giving our Know Your Green talk on all things algae and will be providing more educational programs this summer through film screenings and citizen science volunteer opportunities.
St. Johns Riverkeeper, Algae in the St. Johns, Palatka

What You Can Do: Live River Friendly

Please help us raise the alarm on this serious clean water issue!

REPORT your algal blooms sightings to St. Johns Riverkeeper by

  1. Contacting St. Johns Riverkeeper directly (call, email, or via social media).
  2. Joining our expanding River Patrol and be our eyes and ears of the River! Download the free Water Rangers app and joining our “St. Johns Riverkeeper team” group.
  3. Contacting the Florida Department of Environmental Protection at

REDUCE your environmental footprint and DON’T FEED THE ALGAE – say “no” to fertilizer! This is the time of year residents are greening up their yards by planting flower and applying fertilizer and pesticides. Even if your home is not waterfront, all of our yards have an impact and are connected to River. Learn how to live a more River Friendly lifestyle at

EDUCATE yourself and others by attending one of St. Johns Riverkeeper’s educational programs. Visit to find the right one for you.

SPREAD the word! Share what you know with your friends and family and encourage them to be more River Friendly.

About Kelly Thompson

Kelly Thompson Outreach Director St. Johns Riverkeeper Kelly's job responsibilities include expanding the St. Johns Riverkeeper's geographic outreach efforts by organizing engaging community events and programs, developing partnerships with local organizations and businesses, and connecting citizens to the water through everyday action opportunities along the St. Johns River. A Georgia native, Kelly grew up spending summers on the coast, where her outside experiences kept her closely connected to the water and everything it touched. With a strong passion for marine conservation, Kelly received her Bachelor of Science in Biology from Rhodes College in Memphis, Tennessee. Before joining the St. Johns Riverkeeper team, she started her coastal career as a Naturalist and Sea Turtle Technician on Sea Island, GA (one of Georgia’s 14 barrier islands) and spent four years working in coastal outreach and education with One Hundred Miles, an environmental advocacy nonprofit on the Georgia coast. In coastal Florida, Kelly has also worked with the Sarasota Dolphin Research Program conducting wild bottlenose dolphin research and coordinated sea turtle rehabilitation and education efforts with Clearwater Marine Aquarium. Outside of work, Kelly enjoys nature photography, kayaking, and a good book. With a recent move to Jacksonville, she is looking forward to exploring the natural wonders of Florida and everything the St. Johns River has to offer.