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Sea Change: Understanding Water Quality in Florida Bay and the Keys
We asked four experts for an update on the region’s water quality.
By Alexandra Marvar
Hundreds of years ago, the low-lying porous limestone peninsula in the southeastern-most corner of what is now the United States of America was a tropical wilderness of wetlands, rivers and lakes. Fresh water flowed from the headwaters of the Kissimmee River to the coral reefs of the Florida Keys, hydrating biodiverse marshes and mangrove forests along the way. Even before Florida became a state in 1845, visitors had already begun speculating as to how to make this region less swampy, and thus more habitable for European colonists. These conversations became plans, and these plans formed the foundation of a more-than-century-long effort to drain the Everglades.
By the 1950s, Florida’s population was growing fast, the Everglades were being developed, and flood control was imperative to progress. The state launched its Central and Southern Florida project: canals, levees, water storage infrastructure, and pumps designed to replumb the southern portion of the state. What Floridians didn’t realize then was that this reworking of water patterns was throwing a delicately balanced system into chaos, creating massive ecological and water quality problems that have taken decades, and billions of dollars, to address. The rescue operation is still a work in progress—one stakeholders say is the single largest ecosystem restoration project on the planet.
Restoration won’t just affect Everglades National Park, according to the National Park Service’s Dr. Erik Stabenau, the Chief of Restoration Sciences at the South Florida Natural Resources Center. Restoring some of the natural balance to this system will also influence the marine environments on which some of the state’s most profitable and unique fisheries rely: Florida Bay and the Atlantic waters east of the Keys.
The project is designed to boost water quality in the Everglades and Florida Bay, Stabenau said, largely by controlling salinity. The right balance of salt and fresh water sets up the ecological conditions that allow good things—like seagrass, and mangroves, and from there, all the species that depend upon them—to grow.
“Fresh water in the dry seasons is what protects the low salinity and the mangrove fringe inside Florida Bay,” he said. “Anything we can do in the restoration program that eventually delivers water consistently through the dry season as it did historically—that will have benefits to the bay. We’re certain of this, because when nature does its part and helps us, we see the response in the bay already.”
Two examples of this, he said, were the large freshwater pulses in the past six years brought about by hurricanes Irma and Ida—both of these events, he said, led to jumps in South Florida’s fish populations. “When you push more fresh water into the system, Florida Bay behaves better,” he said. “The number of fish goes up. You put in more fresh water, the fish grow larger, faster, earlier in their [lifecycle].”
But when it comes to water quality in Florida Bay, salinity is just the tip of the iceberg.
WHAT IS WATER QUALITY?
When we think of water quality, we might think more about pollution, rather than salt water versus fresh water, but it isn’t so cut and dry. To understand water quality, scientists need data on a few separate aspects of the water’s physical, biological, and chemical conditions.
Physical water quality encompasses factors like salinity, temperature, dissolved oxygen, turbidity and pH. In Florida, these factors are measured across a wide-ranging network of hydrologic monitoring stations run by entities including the United States Geological Survey, the National Park Service, the Audubon Society, and Florida International University, among others. Biological quality is measured by the presence, condition, and numbers of species of plants, fish, algae, viruses, and other organisms living in the water.
Then, there is the chemical side of water quality, which concerns nutrients, such as nitrogen, phosphorus, and carbon sulfides. These are harder to measure, according to Dr. Henry Briceño, who heads the Water Quality Monitoring Network research group at Florida International University.
Briceño has been monitoring nutrient levels in Florida’s waters over the past 30 years. Looking at the data, Briceño said that generally: the nutrient concentrations in Florida Bay and off the Keys are rising (which means that the water quality is declining).
“There are some fluctuations, but we see a general increase” in nutrient concentrations, he said, “likely because of anthropogenic inputs.” In other words: Where there are more people, there is more pollution.
Human-made chemicals, like fertilizers and pesticides, affect the chemical quality of the water by altering its nutrient levels, which might make it more or less hospitable for certain species. A March 2022 state-by-state water quality report published by the Environmental Integrity Project noted that Florida’s toxic algae blooms, exacerbated by residential lawn care and agricultural chemicals, have become “an almost annual event.” Meanwhile, Florida ranks in the country’s top states for factors like “acres of lakes deemed too polluted for swimming and aquatic life” and “most square miles of polluted estuaries,” according to the report.
That said, some water quality projects in South Florida have had a positive impact. “We generally saw some slight improvements—declines in those fecal contamination markers— that we could possibly attribute to the transfer from septic tanks to a central sewer system in the Florida Keys,” Briceño said. “That’s a good sign that the removal of our septic tanks—that was a positive thing. So, we’re continuing that work. But the inputs of nutrients from other sources are still occurring.”
IS WATER QUALITY IN FLORIDA BAY AND THE KEYS GOOD OR BAD?
So, is South Florida’s coastal and marine water quality “good” or “bad”? Karen Bohnsack at the Florida Keys National Marine Sanctuary, says that while data can show us long-term and short-term trends, there’s no black-and-white answer to the water quality question.
“Unfortunately, there is not a consistent pattern of water quality throughout South Florida,” she said. “It varies based on how the water is flowing, where the rain’s falling, how far along we are with some of the restoration projects that have been put into place.”
Bohnsack is the Associate Director of Water Quality and Ecosystem Restoration at the Sanctuary. Her specific focus is on water quality within the Sanctuary’s boundaries, but her team knows the Florida Keys are influenced by waters from the Gulf of Mexico, the Caribbean, the Southwest Florida shelf, even the water in the Mississippi River, which drains 40 percent of the United States, not to mention the many inputs within Florida. All of this, Bohnsack says, eventually makes its way to the Keys. That means a lot of factors are well out of her control.
This is where the South Florida Ecosystem Restoration Task Force comes in. An umbrella group of 14 local, state and federal agencies and tribal groups, the Task Force has since 1996 helped coordinate Everglades restoration. With every passing year, Bohnsack says, there is greater interconnectivity, partnership, and awareness that water management, infrastructure, and restoration decisions made upstream affect the system all the way to its farthest southern reaches.
“We are 20-plus years into Everglades restoration at this time, and it’s a really exciting time, because we are finally reaching the point where some of these projects are being put online, and enough of them are in place that we can actually start to anticipate and see benefits associated with them,” Bohnsack said. “Just understanding that we need to make sure that we’re thinking all the way downstream when these decisions are being made at a project level is a sea change in how people are thinking about these natural resources across the state—and collaborating to protect them.”
HOW INFLUENTIAL IS WATER QUALITY ON SOUTH FLORIDA’S FISHERIES?
According to biologist Peter Frezza, who previously ran a hydrologic monitoring network in a coastal mangrove zone of Florida Bay, water quality is an important factor in the health of Florida’s fisheries, but he isn’t so sure that a degradation of water quality is the reason some of Florida’s most prized fish populations are in decline.
“That’s just one of the issues,” he said of water quality. Other human factors, from habitat loss, fishing pressure, and other management issues, he says, are worth a hard look. “Direct pressure has way more of an effect [on Florida’s fish populations] than people realize,” he said, “even in a catch-and-release fishery.”
Today, Frezza is the Environmental Resources Manager in the village of Islamorada in the Keys.
“In the very early ‘90s, if you read some of those accounts, they really did think that that was the end of the fishing in Florida Bay. And if you talk to a lot of long-time anglers in Florida Bay, we’ve had two episodes where people just thought, ‘Oh, it’s the end, this is it, it’s over’” with regard to water quality, he said, referencing major algal blooms and seagrass die-offs in recent years. “But you know what? The grass came back, and it came back really quick, and it’s never looked prettier than it does right now. It’s beautiful. There are a few areas out in western Florida Bay where the grass hasn’t fully come back to the extent it was prior to the last die-off, but it’s getting there,” he said.
This ability to rebound is called resilience, and he is “fully confident” Florida’s fisheries are resilient enough to adapt and survive under current conditions. It’s especially helpful, though, he says, when these ecosystems get an occasional break from human pressures—like a “dry January” of abstinence from human interference.
“We’ve had a couple of really good examples of a release of pressure in our environment, with the last one being during the pandemic,” he noted. Two hurricane events, in 2005 and 2017, led to restricted access and even closures of parts of Everglades National Park. Following those closures, the rebound of game fish populations was “nothing short of remarkable,” Frezza recalled. “What happens during those events, when there’s a release of pressure—it’s amazing,” he said. “You’ll hear that over and over from people.”
As of now, however, those releases only result from acts of God. “We’ve just got to give it a chance [to recuperate once in a while]. And there are ways to give it a chance,” he said. “We could certainly manage better.”
MANAGING FOR RESILIENCE
Stabenau at Everglades National Park says these vividly positive environmental responses to releases in human pressures are “an important indicator of how resilient the system actually is.”
“It’s not unusual to talk to somebody out in the park and have them say, ‘Hey, you know, I was so excited to come down here. I used to fish for this with my grandfather as a child, at this location, with this bait, at this time of year,’ and they want exactly that experience that their grandfather gave them as a child,” he said. “They’re thinking back to five years old, and they’re standing there at 70, and they’re expecting that it’s all exactly the same. Not being the same is being interpreted as a failure of management [on the part of] the Parks.”
That’s isn’t quite right, Stabenau said: Waterways shift; water levels change; ecosystems evolve. Stabenau says his mission is to get people thinking in a more dynamic sense about the park, helping visitors, and colleagues, both see not what they remember, but what’s new, in the dynamic, resilient system that is the Everglades.
It’s a relatively new perspective on parks management, he says, even a cultural shift, and it will take time for people to adopt it. But with the inevitability of increasing human habitation and human pressures in South Florida’s coastal ecosystems, combined with climate change, and with Everglades restoration projects coming online to restore the freshwater balance to the extent humanly—and naturally—possible, there is no denying: This is a system in constant flux.
Some areas struggle with pollution, runoff and wastewater issues. Some areas are seeing positive trends in response to new water quality initiatives, or upgraded water treatment infrastructure. Sometimes water quality is “good,” sometimes it’s “bad.” But the experts paying the closest attention to the largest collections of data aren’t willing to be so black and white about it.
“Come here every year. See what’s new,” Stabenau said. “Experience your park, your way, with your family—but teach your children that they should be coming back again and again, to see how the place is changing, to see what it becomes, to see the system dynamically over decades, and share in that changing system.”
Alexandra Marvar is a freelance journalist based in Savannah, Georgia. Her writing can be found in The New York Times, National Geographic, Smithsonian Magazine and elsewhere.
