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Power plants keep Florida manatees warm. What happens when they close?

A manatee pokes its head above water.
Jefferee Woo
Tampa Bay Times
A manatee swims to the surface for some air at the Manatee Viewing Center at the Tampa Electric Big Bend power plant on Dec. 22, 2023, in Apollo Beach.

It’s a quintessential Tampa Bay image: hundreds of manatees swimming beneath Tampa Electric’s Big Bend plant in Apollo Beach, bobbing like russet potatoes in a pot as they bask in the warm water released by the facility.

For decades, it’s been a Florida winter tradition for locals to delight visitors with this scene. It also shows how much manatees rely on humans to survive. Years of development and change to their natural habitats forced them to adapt. Soon, they’ll be forced to do so again.

That’s because as we bent Florida’s waterways to our will — diverting rivers, draining water that fed springs, paving over creeks — manatees had to find other sources of warm water to keep them alive during the winter. More than half of the state’s manatees now depend on power plants to survive, according to the Florida Fish and Wildlife Conservation Commission. But in an ironic twist, human efforts to help the environment and address climate change will mean that these plants, powered by fossil fuels, will eventually be converted to cleaner energy sources that don’t involve warm-water discharges. The wildlife commission estimates that this transition will happen within the next 30 years for all the major sites manatees visit.

That’s an existential threat to the species, experts said, because manatees can die of cold stress in water that’s below 68 degrees.

“We must begin now to avoid catastrophic losses of the Florida manatee population,” reads the commission’s Florida Manatee Warm-Water Action Plan, published jointly with the federal Fish and Wildlife Service. It calls the loss of warm-water hubs “one of the most significant remaining threats to the continued existence of the Florida manatee.”

And while 30 years sounds far away, Florida has yet to settle on a plan to solve it, despite knowing about this looming problem for decades. That report urging action was first prepared in 2004, with an update five years ago. It lists questions that still need to be answered by research.

Progress needs to be made soon, said Patrick Rose, executive director of the Save the Manatee Club.

“We’ve just changed the landscape so much that we now have to be very strategic about how we’re going to allow them to readapt as we’re changing the landscape again around them,” he said. “That can’t happen overnight.”

Manatees swim together at the Manatee Viewing Center by Tampa Electric's Big Bend Station on Jan. 17 in Apollo Beach.
Martha Asencio-Rhine
Tampa Bay Times
Manatees swim together at the Manatee Viewing Center by Tampa Electric's Big Bend Station on Jan. 17 in Apollo Beach.

"Human-dominated ecosystems"

The threat posed to manatees by the disappearance of power plant discharges is the likely next chapter of a long history of problems humans have created for the species. Our boat propellers slashed their skin until speed limits on the water helped address the problem. Our pollution impacts the quality of their waters and, by extension, the availability of the seagrass they eat.

That threat was on full display by late 2020, when years of harmful algal blooms fueled by pollution had killed about 90% of seagrass in the Indian River Lagoon, according to Duane De Freese, executive director of Indian River Lagoon National Estuary Program. About 2,000 manatees died in a two-year span, many of them from starvation and malnutrition.

The crisis highlighted how dramatically people have altered manatees’ habitat.

It also showed that in the winter, manatees need warm water and food nearby to survive, something experts have said will have to be considered if officials decide to build artificial sites for manatees to use instead of power plants. When state officials decided to feed manatees lettuce to help stem the die-off, they drew the animals to the feeding area by heating the water adjacent to the warm discharges from the Florida Power & Light plant on Cape Canaveral, where manatees were already congregating.

“Anytime you disrupt the natural balance with human impact, you’re going to get unintended consequences that are hard to predict,” De Freese said. “We are no longer a natural system. The coastal system in Florida and nationally are all human-dominated ecosystems that are responding to multiple stressors up and down the food web.”

Another complication making it difficult to prepare for the future is that there are more immediate threats to manatees.

De Freese said there’s no guarantee the recent die-offs are over.

“We’ve got a long way to go before we’ve got this system recovered,” he said. The extra rain this winter meant more runoff, which could fuel algal blooms this spring, he added.

“I’m guardedly optimistic we’re out of the crisis at the moment, but we’re still so vulnerable to things we can’t control.”

A complex problem, uncertain solutions

Here’s what we do know about fixing this problem: It won’t be easy. Generations of manatees have grown accustomed to the warm water provided by power plants, which is created after the plants draw from natural waterways to cool off the steam boiled by burning fuels like natural gas. That steam turns turbines to create power, the cooler water then helps to convert the steam back into a liquid so it can be reused, and the cooler water is released back into the surroundings at a higher temperature than it came in. The Tampa Electric plant in Apollo Beach alone circulates and warms about 600 millions gallons per day, according to the utility.

Depending on the weather, these discharges can sometimes be even warmer than natural springs.

And manatees tend to be habitual. Mother manatees show their babies the warm-water sites that they will return to for the rest of their lives, said Ron Mezich, the state fish and wildlife commission’s imperiled species management section leader, during a presentation last month in Tallahassee.

Their reliance on power plants is so pronounced that it’s altered migration patterns because many manatees no longer swim south to warmer waters like they once did, said Michael Walsh, a professor of aquatic animal health at the University of Florida.

“Some animals are going to have to learn to go south again,” he said. “How do you take thousands of animals and get them to cooperate without losing a bunch of them?”

When power plants shut down in the past, some manatees opted to stay in the colder water, waiting for the heat to come back on. Some died waiting.

When a manatee gets cold stress syndrome, they can develop lesions on their body similar to frostbite. They stop eating, and their fat reserves waste away until there’s nothing left.

So far, government officials and manatee advocates envision the solution to resemble a network of warm-water sites. Monica Ross, director of manatee research and conservation at the Clearwater Marine Aquarium Research Institute, described it as a “stepping stone” system where manatees traveling long distances to ideal spots can take breaks to get warm, rest and eat.

Some sites will need to be established before the power plant discharges stop, so the manatees can learn where to take refuge when their typical locations vanish. Possibilities include digging out basins that can be warmed by the sun or groundwater, using solar- or gas-powered heaters, or deploying a movable heating system that manatees could follow.

The wildlife agencies’ action plan states that solutions will require “substantial funding,” and “at this point, there has not been any dedicated funding for the efforts.” It lists state government and the power industry among the options for who could chip in. A pump system to temporarily heat the water at just one offline power plant site in 2011, for example, cost $5 million.

Experts agree that the first step to addressing this problem is improving and restoring manatees’ access to natural sites, like springs, so manatees can maximize their use.

When human recreation is prohibited in sections of natural springs, Ross said, more manatees arrive as they begin “recruiting” others from elsewhere. By closely observing behavior like this and understanding where manatees used to go, officials can create enticing environments.

“Before there were power plants, manatees were using creeks and rivers and little mud areas. … Do we still have those resources we used to have for their survival, and how do we enhance them?” Ross said. “What have they been telling us, and how do we help them out?”

Rose, the Save the Manatee Club leader, said utility companies have saved billions by using water from natural waterways to cool their plants, and thus the companies should pay it forward to help manatees’ survival.

Tampa Electric's Big Bend power plant attracts hundreds of manatees each winter.
Luis Santana
Tampa Bay Times
Tampa Electric's Big Bend power plant attracts hundreds of manatees each winter.

Tampa Electric has agreed to be a partner with the Fish and Wildlife Commission to address manatees’ future warm-water needs, said spokesperson Cherie Jacobs, and has had “many meetings” with the commission on the subject. The company has no set timeline for when the Big Bend plant in Apollo Beach will cease warm-water discharges. It just completed a project in 2022 to convert one of the plant’s units from coal to natural gas.

When asked whether Tampa Electric would be willing to help fund long-term fixes, Jacobs said the company “is committed to the safety of manatees and will continue to invest in solutions that ensure their survival.”

As for government action, state and federal wildlife agencies are “still undergoing discussion” about whether a warm-water task force will be convened similar to what existed two decades ago, according to a spokesperson for the Florida Fish and Wildlife Commission.

Rose said he’s “reasonably confident” there’s still time for the gears of government to turn and prepare manatees for what’s coming. He’s 73 now, but remembers working with Florida Power & Light in the 1970s to survey how manatees were using power plant discharges back then.

“I’ve been doing this for 50 years,” he said. “I’m not personally going to be at peace until I know this plan is going to be implemented and manatees are going to be taken care of.”

This story was produced in partnership with the Florida Climate Reporting Network, a multi-newsroom initiative founded by the Miami Herald, the South Florida Sun Sentinel, The Palm Beach Post, the Orlando Sentinel, WLRN Public Media and the Tampa Bay Times.

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