NSF - Measures are in place to offset potential blue-green algae blooms after the U.S. Army Corps of Engineers started Wednesday to schedule water releases from lower Lake Okeechobee, according to the state Department of Environmental Protection.
A news release late Wednesday said the department and the South Florida Water Management District are prepared to use “innovative technology” if needed and noted that algae bloom conditions on the lake have improved in recent weeks. “Harmful algal blooms have a debilitating effect on our ecosystems and our communities,” Gov. Ron DeSantis said in a prepared statement. “That is why, for the first time, I made it a priority to secure dedicated funding to deploy innovative technology to mitigate blue-green algae blooms.”
On Wednesday, the U.S. Army Corps of Engineers Jacksonville District announced it would start releasing water from the lake as heavy inflows from Central Florida and rains across South Florida have caused the lake to reach 16.21 feet, a 1.33 foot increase over the past 30 days, while six weeks remain in hurricane season. The water releases will go through the Moore Haven Lock and Dam on the southwest part of the lake, and the St. Lucie Lock near Stuart. Such releases are closely watched because of harmful algae blooms that have occurred in the past in waterways to the east and west of the lake. The releases will be evaluated weekly and adjusted as conditions evolve, the Army Corps said. “We haven’t made large volume releases from Lake Okeechobee since March 2019, but the rapid rise in the lake level combined with an already active hurricane season that lasts until Nov. 30 has left us with no options in ensuring the safety of those living and working around the Herbert Hoover Dike,” Col. Andrew Kelly, Jacksonville District commander, said in a statement. The state allocated $10 million in both the current budget and in the 2019-2020 budget to invest in technologies to detect and combat algae blooms.
Rivers, lakes, and ponds are recreational destinations for swimming, fishing, boating and more. When cyanobacterial harmful algal blooms (cyanoHABs) form releasing toxins into these freshwater systems, there can be harmful impacts to all wildlife and humans creating symptoms such as nausea, skin and eye irritations, tumor production, and in some cases even death.
Cyanobacteria are a blooming problem across the country, and while there is information available on how toxins act in the water, there is limited information available on how the toxins progress in the air, until now.
H. Dail Laughinghouse IV, a co-author of the study and UF/IFAS assistant professor of applied phycology and Extension specialist in HABs along with the lead author, Myoseon Jang, a UF associate professor in environmental engineering sciences based in Gainesville was joined by five other scientists taking an extensive look at what environmental conditions in the air influence the toxin causing it to deteriorate and spread at varying rates.
For the study, the team conducted several experiments using Jang’s lab and developed at UF known as the Atmospheric Photochemical Outdoor Reactor. The device, which looks like a greenhouse, measures how the toxin reacts, progresses, and decays in a variety of meteorological conditions including ranges of sunlight, humidity, ozone and other gasses.
The team found that the estimated lifetime of microcystin in the air at typical day ozone concentrations can be about two hours. However, the team also learned that the toxin’s reaction varied across atmospheric conditions and consistently decayed quicker when exposed to ambient sunlight. The degree of decay was dependent on the quantity of oxidants such as ozone and hydroxyl radicals in the air that increases with intensity of the sunlight and the amount of air pollutants such as hydrocarbon and nitrogen oxides emitted from human activities.
Based on the chamber study, while airborne algal toxins can rapidly decay in air, residential areas within about 10 miles from a cyanobacterial bloom source could be impacted by the harmful algal aerosols even under a gentle breeze traveling four to seven miles per hour.