One of the basic building blocks of marine life on Florida's coasts is simple grasses that grow in shallow water. Healthy seagrasses are the barometer of a healthy ecosystem.
On a recent ride with the wind whipping our boat guns out of the Fort DeSoto boat ramp, we got to take part in the first mapping of seagrasses since the 2024 hurricanes.
Whitecaps form on normally placid Boca Ciega Bay. The air smelled of salt spray, competing with the scent of engine fumes. Our destination was a cove somewhat sheltered from a nor'easter cooling the heat of the late morning sun.
"This is in southern Pinellas County, so the Skyway Bridge, if you can see it, is out behind me, and then of course St. Pete Beach is to the north of us, and then the city of St. Petersburg is to the northeast of us," said Chris Anastasiou, the head water scientist for the Southwest Florida Water Management District.
It was one of those rare days he got to ditch fluorescent office lights and feel the sun on his face.
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"We're here as part of what we call our field verification work," he said.
And part of that work is getting wet.
Anastasiou dove into the bay and surfaced with a couple of seagrass samples with the melodic names of thalassia — or turtle grass — and halodule. I took a bite of the halodule. It tasted a little nutty and a little salty. One is thicker, the other wispy thin.
Environmental scientist Tara Harter peered down into the bay through a PVC tube. That gives them a preview before they videotape the sea floor.
"So it's got a duct-taped piece of plexiglass on the bottom. It's lovingly known as the seagrass hunter," she said. "It's been around probably longer than myself."
She then lowered another PVC pipe into the bay with a waterproof camera and videotaped the growth on the sea floor. Like most of Tampa Bay, this area got hammered repeatedly by hurricanes Milton and Helene. Anastasiou said these grasses can deal with big storms.
"Storms are like fingerprints. They're unique," he said. "Every storm has its own set of impacts, and it's hard to just make a general kind of prediction on what you would expect to see. Storms have been going on for millennia, and seagrass have been here for millennia, so these grasses have evolved."
He compared their role to that of a "canary in a coal mine."
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"The miners knew it was time to get out, so they, they've been dubbed 'canary of the estuary' because as we see seagrass either expand or contract, that tells us a lot about the overall health of the estuary," Anastasiou said. "We do this for our partners as well as for ourselves. So folks like the Tampa Bay Estuary Program rely very heavily on our maps in order to put out their bay-wide annual report cards, as does Sarasota Bay, Charlotte Harbor. And then further north, we also map from Clearwater Harbor north to just east of Cedar Key."
That's why the water district is so interested.
"Sort of like when you go to the doctor and they take your blood pressure," he said. "This is the way that we take the estuary's blood pressure."
Anastasiou said seagrasses help clean the water, and feed and shelter up to 75% of the region's famous game fish.
Studies show seagrass is thriving in both Boca Ciega Bay and Lower Tampa Bay.
"Both of these areas have experienced a significant gain in seagrass over the last few years," he said. "In fact, we're at record levels of seagrass since we started mapping in the 80s. So this area looks really good, and I think what we saw today was a confirmation that things seem to be doing very well."
One of the reasons is our drought. Even though that's not so good for grass on land, out here, it's kind of a blessing. The lack of freshwater runoff increases the salinity they need to survive.
The last study two years ago showed Tampa Bay has gained more than 1,000 acres of seagrass. But problems with algae clouding the water and bridges that block water flow continue to cause issues in some places.
"Places like old Tampa Bay continue to struggle," he noted. "We've seen seagrass loss there, and it is an area that we're working closely with our partners like the Tampa Bay Estuary Program to come up with some potential solutions for that."
Those solutions could include keeping a lid on pollution and nutrients that flow into the water.
Now that they’ve got the data, they’ll create maps that could be used to heal other seagrass beds that aren’t as healthy as the one in Boca Ciega Bay.
