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Public Radio's Environmental News Magazine (follow us on Google News)


Air Date: Week of

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Manatees, the sea cows that inhabit the waters of Florida, depend on natural warm water springs to survive the winter. But thanks to development, those warm water sources have diminished over the years. So manatees have come to depend on the warm water discharge of power plants. But now, they face losing even these man-made refuges. Angela Swafford reports.


CURWOOD: We usually don’t think of altering an ecosystem as having environmental benefits. But that is the case sometimes with power plants in Florida. With the loss of natural warm water springs over the years, manatees have come to depend on the warm water discharge from power plants to get them through the cold winter months. Now, as these power plants update their technology, manatees stand to lose these warm water refuges, as well. Angela Swafford reports from Crystal River on Florida’s west coast.


SWAFFORD: A small pontoon boat heads toward Crystal River National Wildlife Refuge, about 50 miles north of Tampa. Manatees congregate in large numbers here during the winter to swim in the warm and pristine springs that dot the area. Running deep under an insulating layer of rock, these springs bubble up in small tributaries of the river. Before reaching the area where the group hopes to swim with wild manatees, the tour operator makes sure everybody understands how to interact with the animals.

MARTY: Okay, guys, good morning. My name is Marty. I need to have your attention here for a couple of minutes. I really want to emphasize how important it is to be very, very quiet in the water with the manatee. Splashing sounds, moving your hands too much, moving your feet too much, splashing around, are going to scare them away. And sometimes, if you scare them away, they’re the only ones you’re going to find that day.


SWAFFORD: Spring water here surfaces at a constant 72 degrees. Manatees cannot tolerate temperatures under 68, so many of them are compelled to winter in these canals, swimming back and forth between the warm springs and the cooler gulf water where they feed on sea grass. More swimming and less to eat means each manatee will shed some 300 pounds by the end of the winter.

CHILD: We just saw one!

SWAFFORD: A few minutes after our arrival, a couple of manatees show up, much to the delight of the crowd.

WOMAN: Look, look over there, see it?

MAN: Here it goes, see? You can see the babies tail!

SWAFFORD: Like miniature Goodyear blimps, a 13 foot long adult and a younger, smaller companion swim underneath the pontoon.

WOMAN: I think they’re going away, yes.

SWAFFORD: Their brown backs are criss-crossed with pale scars, a testament to old encounters with boat propellers. But these manatees seem to know that as they get closer to this tour group, belly rubs and back scratches await them.


SWAFFORD: The development of the area surrounding Florida’s waterways has caused a significant decrease in flow rates of the spring. As the soils are paved over, water can’t seep underground. What’s more, some of this water has been diverted for human use. There is even one plan to bottle it as designer water. Though some scientists fear that within the next decade there might not be enough warm water to keep these animals alive.


SWAFFORD: As natural springs deteriorate, man-made warm water refuges have become more important to the animals’ survival. Further south on Florida’s Atlantic coast, an electric power plant discharges tons of warm water every day into a shallow basin adjacent to the port of Palm Beach. Today, several manatees have congregated here, their dark backs bob in the water and their nostrils break the surface every so often. For the past 30 years manatees have become increasingly habituated to wintering at these discharges. Mothers even teach their calves to come to these areas.


SWAFFORD: Winifred Perkins is manager of environmental relations for Florida Power and Light. She says on a given day as many as 500 can gather around a critical effluent.

PERKINS: But it’s not a perfect situation. Whenever you have a situation where a very endangered animal like a manatee depends on something like a power plant, you know, it’s sort of a two-edged sword.

SWAFFORD: This sword has already become apparent. Power companies are using more efficient methods to generate electricity, which means they are discharging cooler water. Also, there is a distinct possibility that within the next five years the power industry in Florida will be deregulated. If that happens, the effort to provide cheaper power may mean older, less efficient plants will be taken off line, further reducing the flow of warm water. There has already been a case in Jacksonville in which nine manatees died when they showed up at a power plant that had temporarily shut down operations.

PERKINS: And they just stayed there and stayed there and stayed there, thinking that the warm water would come back, and it didn’t. And the animal is so sensitive to the water temperature, if it gets too low, what they’ll do is they’ll forego eating, they’ll forego all sorts of things, and they’ll just work at trying to stay warm. And if that warm water isn’t there, they will ultimately perish, and that’s what happened in this case up in Jacksonville.

SWAFFORD: Even when warm water is flowing, manatees might still get into trouble. Some of these power plants are north of the manatees’ range, allowing them to winter where they would not normally be found. A Warm Water Task Force is looking at the downside of that, along with other issues. The U.S. Fish and Wildlife Service established a committee about a year ago. Composed of federal, state, and power plant officials, it studies the impact of industrial warm water discharges on manatees. With fully two-thirds of Florida’s manatee population dependent on 14 power plants, the location of each facility becomes critical. Jim Valade heads up the task force.

VALADE: We’re very concerned about these northernmost sites. There are sites in Titusville, over in the Cape Canaveral area, and we also have sites over in Tampa Bay area which are thought to be pretty far north for manatees. And at these sites—- for example, the one in Titusville-- we’ve got in excess of 400 animals that are wintering at that site.

SWAFFORD: The more northern the site, the farther the manatees will have to swim in the cold to reach their feeding grounds. This poses a particular danger for young manatees.

VALADE: They’re just not built to withstand cold weather temperatures. And if you have a fairly mild winter, you know, the animals do quite well. But we know from experience that if you have a severe winter where the temperatures plunge and it stays cold for a very long period of time— two, three, four weeks--well, then these animals are particularly vulnerable.

SWAFFORD: During the summer, the issue of warm water discharge takes on a new complication: thermal pollution.

VALADE: When you have warm water during the winter, it’s good for manatees. But manatees don’t use the plants during the summer, and so when the plants are discharging during the summer into these warm water areas that are naturally warm and you have this tremendous scouring effect, when you have these heated effluents discharging into the sea grass beds, you know, it has a tendency to destroy the grass beds.


SWAFFORD: Despite the drawbacks of the power plant discharges, officials recognize that manatees are dependent on them. So Florida Power and Light is trying to come up with ways to retool its aging facilities in such a way that manatees are kept warm in the winter and the grass beds are kept cool in the summer. Again, Winifred Perkins with Florida Power and Light:

PERKINS: At Fort Myers, we’re just in the process of re-powering a power plant over there, and part of our design for the new facility is quite interesting. We have put in a helper cooling tower that will cool the water in the summer, but we don’t plan to use that cooling tower in the winter because we want to still be able to provide warm water for the manatees.

SWAFFORD: There are other, as yet untested, ideas for keeping manatees warm. One calls for heating water with solar grids, another to dig pits in the underwater sediment to help the water retain heat in the winter.


SWAFFORD: Back in Crystal River, the water gets progressively colder for the snorkelers who have been swimming since dawn, but they linger for a few last encounters with the manatees.

The Warm Water Task Force will continue to gather data and search for viable solutions. As Jim Valade with the Fish and Wildlife Services says, if this issue is screwed up, as he puts it, we stand to lose hundreds or even thousands of manatees. From Crystal River National Wildlife Refuge, I’m Angela Swafford for Living on Earth.

[MUSIC: John Zorn (performs Ennio Morricone), "The Sicilian Clan," NAKED CITY (Elektra/Nonesuch – 1989)]



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