Seagrass beds are starting to revive along the Indian River Lagoon; but for how long?
Don't cue the ticker-tape parade quite yet, but seagrass is starting to make a comeback in the Indian River Lagoon along the Treasure Coast and Space Coast.
Not a huge comeback, mind you, but after years of losing thousands of acres of seagrass beds throughout the 156-mile lagoon — up to 95 percent of their coverage in some areas over the last 20 years, according to a University of Florida report — any turnaround is welcome.
Why? Because seagrass beds are an essential part of the lagoon.
Seagrasses are known as a "foundation species" in the lagoon, said Kathryn "Katie" Tiling, at the Florida Oceanographic Society in Stuart.
"Seagrass beds harbor lots of native fish species, and they're nurseries for lots of popular game fish," said Capt. Paul Fafeita of Vero Beach, a fishing guide and president of the Clean Water Coalition of Indian River County.
"Seagrass is crucial for their existence as well as other species from crabs to wading birds. If you lose seagrass, you lose the ecosystem."
Seagrasses also help keep lagoon water clean by holding down sediment. "When you lose seagrass, the water becomes more turbid," Tiling said. And when water gets turbid, seagrass can't get sunlight to photosynthesize food, so you lose more seagrass. "It's a snowball effect," Tiling said.
Environmental, economic impact
According to the St. Johns River Water Management District, 2.5 acres of seagrass can support:
- up to 100,000 fish
- up to 100 million invertebrates such as worms, clams and snails
- $5,000 to $10,000 in economic activity
So, what's been killing seagrass in the lagoon?
The short answer: nutrients, particularly nitrogen and phosphorus.
Seagrasses feed on nutrients just like the grass in your yard, but too much nitrogen and phosphorus spurs the growth of algae.
"Algae utilizes nutrients faster than seagrass," Tiling said. "So algae grows faster than seagrass and can eventually choke it out."
Where the nutrients come from varies depending on the section of the lagoon. So do the reasons nutrient loads are lower this year and seagrass is coming back.
"This year we've definitely seen some, a little, recovery," said Tiling. "Not having Lake Okeechobee discharges has definitely been a benefit because we've had a lack of turbidity and plenty of salinity."
Seagrass beds seeing signs of growth in the lagoon can be found at Bessey Cove north of Sailfish Point, near Boy Scout Island and behind the society's Coastal Center, where staffers take school kids seining, which involves pulling long nets through the shallow water to see what kinds of critters show up.
"In the years when we had no seagrass, we'd get virtually nothing at all," said Zack Jud, the nonprofit's director of education and exhibits. "But this past summer, all the seining we did resulted in real high biodiversity. That shows you just how vital seagrass is. It's one of the foundations of a healthy lagoon."
Tiling cautioned, however, the seagrass in the lagoon is "way far off from what it should be like."
To see what seagrass in the lagoon should be like, you'd have to go back to 2012 or early 2013, before the "lost summer" brought on by massive Lake O discharges to the St. Lucie River.
"Since the 2013 discharges, we've seen seagrass decline more and more over the years," Tiling said. "Growth would perk up a bit in the years with no discharges, but overall it's been a downward trend."
It's "extremely hard" to say how many discharge-free years would be needed for the seagrass beds to fully recover, Tiling said.
"I can say it took decades of active restoration for seagrass in Chesapeake Bay to come back," Tiling said. "It doesn't take much time to crush the system, but it takes a lot more for the system to recover."
St. Lucie and Indian River counties
The seagrass beds from south of Fort Pierce to Vero Beach "are probably the healthiest in the entire lagoon," Tiling said.
The reason: The Fort Pierce Inlet does a good job of flushing out dirty water and bringing in clean ocean water.
But the inlet can't keep the lagoon around it pristine.
In June, an influx of nutrient-rich water coming down Taylor Creek and the C-25 Canal caused a blue-green algae bloom in Harbortown Marina, where the creek empties into the lagoon in northern Fort Pierce.
Fortunately, the cleanest stretch of the lagoon contains some of its most important seagrass beds:
- Off Bear Point south of Fort Pierce
- Just north of Florida Atlantic University's Harbor Branch Oceanographic Institute
- Off the Oslo Road boat ramp and the Moorings Flats, where 24 tethered buoys encircle 440 acres of the lagoon's most delicate habitat.
The protected area is the result of a four-year, nearly $20,000 effort by Vero Beach Rotary clubs, known as the Rotary Initiative for Submerged Seagrass Awareness (RISSA), to warn boaters to keep off shallow seagrass beds.
The Rotarians' work has helped protect that seagrass bed, Fafeita said, but others need protection as well.
Indian River County is "the least-patrolled county on the Florida east coast," he said. "The FWC (Florida Fish and Wildlife Conservation Commission) says there aren't enough boat owners here to justify more patrols."
Local law enforcement agencies only take their boats out onto the lagoon "for fatalities and parades," Fafeita, a former Indian River County sheriff's deputy, added. "I know patrolling the lagoon is expensive, but it's vitally important."
Much of the lagoon in Brevard County suffered through a 22-month algae bloom in 2017 and 2018, said Lori Morris, an environmental scientist at the St. Johns River Water Management District.
"Fortunately, it hasn't been present in 2019," Morris said. "That's helped a lot because it allowed the seagrass to have a full growing season through the spring and summer. I wouldn't call it a recovery, but the seagrass beds have spread out a little more."
The exception: the Banana River, where brown tide lingered this year until the end of July to early August.
"That's not giving the grass a chance to grow," Morris said.
Seagrass is recovering in most of the northern lagoon this year, said Chuck Jacoby, supervising environmental scientist at the St. Johns River Water Management District.
"There hasn't been a tremendous amount of rainfall" and there have been successful efforts to reduce the amount of nutrients, primarily nitrogen and phosphorus, in the water that feed algae blooms, he said.
Those efforts include dredging projects to remove muck holding bloom-feeding nutrient, improved stormwater detention and septic-to-sewer conversions.
In recent years, communities along the lagoon also have enacted summer fertilizer bans to keep runoff out of the water, but it's still too early to determine what effects they've had.
"This is a start," Morris said. "Recovery won't happen overnight. It will take a long time because there's so far to go."