Is spraying weeds in Central Florida lakes, contributing to Southwest Florida’s water crisis?

Reporter: Lauren Sweeney
Published: Updated:

Scott Wilson is not a scientist. He’s a pastor and a fisherman with a passion for the Kissimmee Chain of Lakes where he spends most of his time off.

“I’ve grown up on this chain of lakes since I was 4 years old, and I love this part of Florida more than anywhere else,” he said, getting choked up as he tried to get the words out.

Wilson claims since 2012, he’s seen an excessive amount of chemical spraying done near his fish camp.

The Florida Fish and Wildlife Commission does maintenance control throughout Florida to keep populations of invasive plants, or weeds, low.

“Invasive plants degrade and diminish Florida’s conservation lands and waterways. Decaying plants in lakes release nutrients that help algae to grow,” said Carli Segelson, a spokesperson for FWC.

QUIZTest your knowledge on the SWFL water crisis

Reports from the agency show thousands of pounds and gallons of various chemicals are applied in waterways all over the state.

FWC contracts with licensed pesticide operators to conduct the spraying, which Wilson feels is leading to the problem.

He thinks the contractors are over-spraying and not communicating with each other, leading to massive sections of open water which were once filled with lush vegetation.

When he took to Facebook to complain about how much spraying he has seen, a scientist in Southwest Florida came up with a hypothesis.

“Glyphosate and other herbicides are one of the things that I think could be leading to an excess of nutrients in the water. And the excess of nutrients in the water leads to all kinds of harmful algae blooms,” said Dr. James Douglass.

Douglass, an ecologist who normally studies seagrass in salt-water, has not conducted any research on the chemical herbicide glyphosate.

He said he’d like to team up with a freshwater researcher at the University to see how much impact the chemical glyphosate may have on algae blooms if he can get funding.

READ MORE: Thousands claim weed killer causes cancer

His interest sparked the attention of a nature documentarian who shot video from Wilson’s boat. That video was shared by consumer advocate Erin Brockovich and went viral.

Within a month more than 150,000 people have signed an online petition calling on the state to stop spraying chemicals in the water to control weeds.

Further research needed

The interaction between the glyphosate and cyanobacteria, or blue-green algae, was studied at Bowling Green University in Ohio almost a decade ago.

“We showed that one, that the glyphosate was not inhibitory to the cyanobacteria,” explained Bowling Green Professor Dr. Michael McKay. “… the glyphosate didn’t kill the cyanobacteria and two, they seemed to be able to acquire enough phosphorus for them to grow from the glyphosate alone.”

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The two researchers were not able to secure more funding to study the effects of glyphosate on cyanobacteria further, but say more research is needed.

“In your case, it’s [glyphosate] being applied directly to lakes or rivers, so it’s quite a different application with different effects,” said Dr. McKay.

His colleague, professor of biological sciences Dr. George Bullerjahn, agrees.

“That’s where I would like to see more research,” he said. “Is glyphosate application as an herbicide to control aquatic weeds– is that tipping the balance in favor of cyanobacteria which is unaffected by the glyphosate?”

But FWC claims there is a lot of research that goes into determining how to control invasive plants in Florida.

“Research has shown that keeping populations of these plants at low levels [Maintenance Control], reduces the build-up of decaying plant material and therefore less nutrients are released into the system,” said Segelson, adding that the agency partners with universities to find the most environmentally effective solutions.

“[If you don’t control the weeds] you end up with very low oxygen concentrations in your lakes and you end up with fish kills if these plants are not controlled. Another thing they do is harbor insect larvae, in particular, mosquito larvae,” said Dr. Jason Ferrell, the director for the University of Florida’s center for aquatic invasive plants.

PDF: Rounding up the evidence

In an interview with WINK News, Dr. Ferrell emphasized that the chemicals being used in the water have gone through rigorous EPA approvals.

“This is not DDT. This is not Agent Orange. It’s things that are very sound and have been investigated thoroughly for decades,” he said.

After a television station in West Palm Beach ran a segment regarding the push to ban aquatic weed spraying, Ferrell wrote an open-letter to share his perspective.

In it, Ferrell claimed the solution to the algae crisis is “incredibly complex” and one that scientists and legislators “differ over which path to take.”

“Though we all agree that something needs to be done, our data and experiences teach us that stopping the management of invasive plants will have a number of negative consequences that will surely outweigh the positives,” he said.

MORE: Full the full letter from Dr. Jason Ferrell

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