Runoff from Farms, Lawns, Septic Tanks Fuel Toxic Algal Bloom on Florida Coast That may Last a Few More Years, Scientists Say

Scientists say that water runoff from farms, lawns, and septic tanks is what causes the toxic algal bloom along the Florida coast. According to calculations, the toxic algae might remain in the coasts for a few more years.

According to experts, nutrients that have been washing off the land in the wake of Hurricane Ian are now feeding a red tide bloom that has been present along the coast of Florida for a few weeks.

Red Tide, Karenia Brevis

In the Gulf of Mexico, red tide (Karenia brevis), a naturally occurring organism, can occasionally bloom to toxic levels.

However, research indicates that nutrients from lawns, farm fields, and septic tanks are fueling red tide blooms near the coastline, increasing their frequency, duration, and intensity.

Larry Brand, a water quality expert and scientist, says that he doesn't see any convincing evidence that hurricanes cause red tides, but once one has begun, a runoff will exacerbate it. Brand is also a professor at the University of Miami.

The initial conditions for the bloom were not set by Ian, but rain and storm surges have contributed to its current spread from the Sarasota region south to Marco Island, NBC 6 South Florida reports.

Multiple locations along the Southwest Florida coast have reported cell counts of 1 million and higher.

Numerous beaches in the area are covered in dead fish, and on Wednesday an exposure advisory was issued by the Florida Department of Health in Collier County.

Brand and DOH both agree that the intensity and length of the bloom are influenced by nutrients that run off the landscape. DOH said that once inshore, the opportunistic organisms can feed their growth with nearby nutrient sources. Blooms typically last through the winter or the following spring, but they occasionally can last for more than a year.

DOH Advises Southwest Florida Residents

People who live near the coast should ensure that their air conditioning filters are maintained per the manufacturer's recommendations, according to DOH.

DOH added that residents may decide to wear masks if they are outside near an affected area, particularly if onshore winds are gusting.

Carly Jones, the spokeswoman for the Florida Fish and Wildlife Conservation Commission, said that microscopic algae and polluted waters can be pushed away from the coast by offshore winds.

The most recent FWC report indicates that northern Lee and Sarasota counties have the highest red tide counts.

Jones said that when the red tide organism, Karenia brevis, is present and winds blow onshore, some people will experience respiratory irritation, which can cause symptoms such as coughing, sneezing, tearing, and an itchy throat.

The respiratory effects on those on the shore are typically minimized by offshore winds. People with severe or persistent respiratory conditions, like emphysema or asthma, are advised to stay away from red tide areas by the Florida Department of Health.

The DOH advises against eating or even just collecting shellfish from this area at this time because red tide can contaminate it.

However, according to the press release, locally caught, correctly cleaned, and properly cooked fish can be consumed.

If a person comes into contact with water containing toxic algae, DOH advises thoroughly washing both the person and all clothing.

2017 Algal Bloom

CBS News reports that Hurricane Irma stirred up nutrients in the 2017 toxic algae bloom. John Cassani, the Calusa Waterkeeper, has been following the bloom online.

Cassani has heard that fewer gamefish species are being observed than before Hurricane Irma in 2017. It is primarily foraging fish, but the majority of them are so decomposed that the species cannot be identified, according to Cassani.

Five years ago, Hurricane Irma incited nutrients in the Lake Okeechobee-Caloosahatchee River system, which led to a significant blue-green algae bloom and red tide in the river that made the following summer all but uninhabitable.

For both blooms, Lee County was included in a state of emergency.

According to some scientists, the conditions that followed Hurricane Ian will be similar between now and 2024's spring.

The red tide caused by Hurricane Irma persisted from the fall of 2017 to the spring of 2019.

According to Cassani, it is a neurotoxin. In response to the red tide, certain neurological symptoms have been identified. Asthma sufferers are also visiting emergency rooms. Inflows frequently occur during a bloom. It is an uncontrolled pollutant, FOX News reports.