WEEKI WACHEE — Volunteers again are ridding Weeki Wachee Spring of "witches" — witch's hair, actually.
That's the name old-timers bestowed on the dark strands of bottom-growing Lyngbya algae, an environmental nuisance, said volunteer Doug Brainard.
Brainard heads a group of Spring Hill Central Rotary volunteers, joined by a group from the Brooksville Rotary, that launched an effort last year to clear the spring and its river outlet of the algae, which smother the growth of good aquatic grasses — eelgrass in particular, a lush food for manatees.
This year's effort began Saturday and will continue with eight more two-hour public work sessions through early December.
Last year's plucking of algae, conducted with Weeki Wachee Springs State Park management and scientists from the Southwest Florida Water Management District, has shown signs of success.
"In areas where clearing was done, we're seeing some regrowth with eelgrass, which is very encouraging," Chris Anastasiou, senior environmental scientist with Swiftmud, said after a recent site visit.
While Lyngbya algae is a native species, it's noxious when abundant, Anastasiou said.
Scientists say the algae are caused by increased nitrates that have seeped into the Floridan aquifer.
"Once it gets a foothold, it grows like a weed," Anastasiou said.
"Algae come in when the eelgrass dies out," he explained. "Remove the algae and it gives grass a chance to regrow. Research says once you get the native grasses back, it is hard for the algae to come back."
Hard but not impossible, park manager Toby Brewer cautioned.
"I relate taking out algae to dusting your house. You know the dust will come back, and you know the algae will come back. But if we can get it to the maintenance level, we can help the grass come back," Brewer said.
"We're finding now that as long as there's steady maintenance, it is controllable," Anastasiou confirmed.
And it's a low-cost effort, Brainard noted.
"I think it's wonderful that we found something that works," he said.
Armed with leaf rakes, volunteers — from 30 to 65 at last year's outings — merely lift algae mats from the floor or dip dead pads from the water surface, depositing the harvest into mesh dive bags provided by Swiftmud.
Bags are hoisted onto a flatbed trailer, where the simple plant organisms are left to dry.
"It turns powdery and makes a rather good organic material," Anastasiou said. "It's used as fertilizer on gardens."
The decomposing algae strands have been spread on parkland.
Scuba divers from local diving clubs have scooped algae mats from the headwaters. Waders have tackled growths around the perimeter and about 100 square feet into the river.
"So, people are in up to their knees or waist or chest," Brainard said.
The water temperature is a constant 72 degrees.
"We want people to wear water shoes as there are rocks on the bottom," he added.
Rotary provides a good supply of rakes.
Adults must remain with any children taking part. Everyone must sign a waiver of liability. Participants are invited to bring covered dishes for picnics after the work sessions.
The next step in the program will involve the restoration of grasses.
Awaiting assembly at the park is a dismantled greenhouse, discarded by Silver Springs State Park, in which eelgrass seedlings will be raised. The seedlings will be grown on coconut mats, and the mats then deposited in the spring and river, Brewer said.
"The matting gives protection until the roots get established," he said, explaining that manatees rip out tiny plants along with their roots, whereas the mammals mow off just the top growth from grass in the mats.
Anastasiou is excited about the propagation plans.
"We're hopeful and optimistic," he said. "Stay tuned."
Contact Beth Gray at [email protected]