JUDY WOODRUFF: The growth of an algae known as red tide has exploded in Florida this year,
growing bigger and lasting longer than years before.
It has killed huge numbers of marine life and dealt a hard blow to the Gulf Coast economy.
As William Brangham reports from Sanibel Island, there are many causes driving this red tide,
including warmer waters tied to climate change.
And there are other questions about what role humans are playing.
It's part of our weekly series on the Leading Edge of science, technology and medicine.
WILLIAM BRANGHAM: This is now a typical morning on Florida's Gulf Coast, not a tourist in
sight, just work crews cleaning up the daily toll of dead fish.
They were killed by red tide, an almost annual bloom of algae in the Gulf of Mexico.
At high levels, the algae release a neurotoxin that's deadly to marine life.
It poisons them or makes it so they can't breathe.
But this year's bloom, which actually began last fall, has been particularly bad.
WOMAN: It now spreads across 130 miles of coast.
MAN: Thousands of dead fish floating along Lido Beach.
MAN: This red tide bloom is being called the worst in more than a decade.
WILLIAM BRANGHAM: In the last few months, red tide has killed dolphins, sea turtles,
manatees, even a 26-foot whale shark.
DR.
HEATHER BARRON, Veterinarian: Definitely some deformities here.
WILLIAM BRANGHAM: Veterinarian Dr. Heather Barron runs the Clinic for the Rehabilitation
of Wildlife on Sanibel Island.
These baby loggerhead sea turtles just came.
Barron suspects that they or their mom was poisoned by the red tide.
DR.
HEATHER BARRON: There's probably not a whole lot that we're going to be able to do for
them.
WILLIAM BRANGHAM: She says they have seen four times the number of sea turtles poisoned
by red tide this year.
DR.
HEATHER BARRON: It is overwhelming and catastrophic, the number of patients that are coming in.
We have had as many as 100 patients come in, in two days, all affected with red tide, way
out of the ordinary.
And so, when that happens, one of the things that you sometimes have to do is be able to
triage those animals and decide who are you likely to be able to save, who needs help
the most, and who are you probably not going to save regardless.
WILLIAM BRANGHAM: This pelican came in near death several weeks ago.
But after intensive treatment, he seems to be turning the corner.
So too are these sea turtles.
DR.
HEATHER BARRON: I think even if you're not a bunny hugger, like I am, even if you don't
care about the wildlife, you should care about what that means for your health and your children's
health and your pets' health and your food supply's health.
It's not just wildlife that is going to be affected by this.
WILLIAM BRANGHAM: While the red tide is obviously devastating to wildlife, it's also difficult
for humans as well.
The toxins emit a terrible smell.
They burn your eyes.
They burn your throat.
And, as you can see, nobody is on these beaches.
Florida's red tide has been brutal to tourism, blanketing more than 100 miles of Southwest
Florida.
Here on Sanibel Island, the Chamber of Commerce estimates $11 million in lost income in just
the first half of August.
TRASI SHARP, Over Easy Cafe: We're probably off about another 45, 50 percent of what we
usually do this time of year.
WILLIAM BRANGHAM: Trasi Sharp owns and runs the Over Easy Cafe.
It's a small breakfast and lunch spot in Sanibel just a few blocks of the beach.
TRASI SHARP: Somehow, we will get through this.
We're hoping it doesn't last at this pace for too long, but it's scary.
BEN BIERY, Charter Boat Captain: You couldn't drive 100 yards without passing 1,000 or 10,000
dead fish.
WILLIAM BRANGHAM: Ben Biery is a charter boat captain on Sanibel.
He makes his living taking tourists out to fish and picnic and swim, things that many
people just don't want to do right now.
BEN BIERY: I know that, as captain, my business for the month of August was down somewhere
around 80 percent.
WILLIAM BRANGHAM: Eighty percent?
BEN BIERY: Yes.
I don't think there's anyone that's in the tourism business in our area right now or
in any business that's on the water that isn't -- isn't really suffering right now.
WILLIAM BRANGHAM: In fact, things have been so slow for Biery, that he's volunteered his
boat to scientists who are studying the red tide, like his friend Dr. Rick Bartleson.
Bartleson is an ecologist with the Sanibel-Captiva Conservation Foundation.
He's checking the water at various spots, measuring the concentration of red tide cells.
He says, with a usual red tide, one that will kill some fish, you would see 100,000 to 200,000
red tide cells per liter of water.
But this year, the red tide has been 10 times worse.
RICK BARTLESON, Sanibel-Captiva Conservation Foundation: Instead of 200,000, we're seeing
two million or 20 million cells per liter.
WILLIAM BRANGHAM: I mean, that's a huge jump up.
RICK BARTLESON: Right.
The other day, we saw 40 million cells per liter at a kilometer off the coast.
WILLIAM BRANGHAM: While the red tide has been disastrous for the Gulf, this summer, it's
been compounded by a bloom of blue-green algae in Florida's freshwaters.
It's created a perfect storm for fish, wildlife and humans and it's leading some to wonder
if one is exacerbating the other.
STEVE DAVIS, Everglades Foundation: You can see the green algae here on the Cape Coral
side.
WILLIAM BRANGHAM: The Everglades Foundation's Steve Davis took us along the Caloosahatchee
River about 70 miles east to show us one source of the problem.
For thousands of years in Florida, water flowed down into Lake Okeechobee, where it flooded
out and south through Florida's Everglades marshes.
But as farming expanded around the lake, Lake Okeechobee was dammed up, forcing that water
to the east and to the west.
STEVE DAVIS: The massive volumes of freshwater that are released from the lake to the Caloosahatchee,
they result in harm.
WILLIAM BRANGHAM: Davis says this causes two problems.
One, that freshwater kills crucial habitat that needs saltier water.
And, two, that water is so polluted with runoff from farms and towns, that it could be delivering
a huge nutrient boost to the red tide.
STEVE DAVIS: When you think about red tide, it's really another bloom of algae, but offshore.
And these blooms of algae, they require large loads of nutrients in order to sustain themselves.
And it's kind of like thinking of a wildfire that requires fuel in order for it to continue
burning.
WILLIAM BRANGHAM: Davis and others argue water needs to again flow south, like it once did,
to address both the blue-green algae and any potential impact on red tide.
But the powerful agricultural industry in Florida has successfully stymied these efforts
before.
NARRATOR: It's killing sea life, battering our economy, and making people sick.
And it's fair to blame Rick Scott.
WILLIAM BRANGHAM: And now, ahead of the midterm elections, water quality is a central issue.
NARRATOR: A hundred million dollars from water protection.
TRASI SHARP: We need the state and federal help.
There's industry and farming that dumps into the waters of Okeechobee, but also it's on
everyone, fertilizers in people's yards, the dumping of waste of various companies along
the river.
We just need to do something, or this is going to last generations.
BEN BIERY: That's all I care about this election, is I want people that are going to get out
here and do something and make things better, that are going to make it possible for me
to continue to do what I love for a living.
WILLIAM BRANGHAM: A strong storm or cold front could break up this current red tide.
And Tropical Storm Gordon, which just passed over Florida, may have done just that.
But it's just a few months until the next potential bloom reemerges from the Gulf.
For the "PBS NewsHour," I'm William Brangham in Sanibel, Florida.
JUDY WOODRUFF: Such important reporting.
Thank you, William.