Could blue-green algae be creeping into Treasure Coast waters without Lake O discharges?
Is blue-green algae starting to creep into Treasure Coast waters without Lake Okeechobee discharges?
Possible bloom sightings have been reported to TCPalm this week off Taylor Creek near the Indian River Lagoon at Fort Pierce and in a canal along the South Fork of the St. Lucie River in Stuart.
The bloom seen Monday and Tuesday at Harbortown Marina at the mouth of Taylor Creek in Fort Pierce stretched along a dock bordered by mangroves, said Rory Loveridge, a southern Indian River County resident.
"There was a ton of it Monday and there's a lot more today," Loveridge said Tuesday morning. "I'll bet it covers three times the area today as it did yesterday and is twice as thick."
As a native Floridian, Leveridge said he recognized the bright green scum.
"I knew what it was right away," Loveridge said.
Another apparent bloom seen Sunday in a canal behind houses on Harbor Street in Stuart disappeared with the outgoing tide, said Jeff Brightly, a homeowner who reported the algae to TCPalm.
"We've had blooms in the canal twice, in 2016 and 2018," Brightly said. "And this one looked just the same."
A photo of the Taylor Creek bloom "certainly looks like some type of algal film on the water," said Zack Jud, director of education and exhibits at the Florida Oceanographic Society in Stuart, but it’s not necessarily blue-green algae.
"There are other types of algae that can create a similar green surface film," Jud said.
For example, a bloom reported in mid-July at Outboards Only, a marina on the St. Lucie River that was choked with toxic blue-green algae in 2016, turned out to be Carteria cordiformis, a type of green algae that doesn't produce toxins.
It's up to the Florida Department of Environmental Protection, Jud said, to "come out and sample the bloom and give us the identity of the organism causing the green film."
Lake O not the cause
Whatever the type of algae, neither bloom can be tied to Lake Okeechobee discharges because:
- No lake water is being sent east to the St. Lucie River. In fact, since Aug. 14, about 1.6 billion gallons of water from the C-44 Canal connecting the lake and the river has flowed into Lake O.
- Taylor Creek and the C-25 Canal are not connected to Lake Okeechobee. There is a different Taylor Creek that flows into northern Lake Okeechobee, but the two aren't connected.
Heavy rains are the most likely cause of the Taylor Creek bloom.
The C-25 Canal drains a large area of farmland in northwestern St. Lucie County and empties into the Indian River Lagoon via Taylor Creek in northern Fort Pierce.
Since Aug. 1, that area has received about 8 1/4 inches of rain, nearly 3 1/2 inches more than normal, said Peggy Glitto, a meteorologist at the National Weather Service in Melbourne.
Water was flowing out the C-25 Canal into Taylor Creek at a rate of about 409 million gallons a day late Tuesday morning, according to data from the South Florida Water Management District.
In July 2018, a blue-green algae bloom in the C-25 Canal at the 25th Street Bridge in Fort Pierce contained minute amounts of the toxin microcystin.
"So it’s entirely possible that we are seeing another bloom," Jud said, "since dirty fresh water is currently being discharged into the Indian River Lagoon from the canal."
Massive algae blooms in the St. Lucie River — like those in 2013, 2016 and 2018 —occur only during massive Lake Okeechobee discharges.
"Even when local rainfall causes freshwater runoff to pour into the estuary, we don’t see blooms," Jud said. "This doesn’t mean that cyanobacteria cannot bloom in other water bodies that are not connected to Lake Okeechobee."