November 11, 2013 at 10:15 pm #937MikeKeymaster
CARA BUCKLEY/HERALD STAFF
POISONED BY RED TIDE: This loggerhead turtle and seven others are
tended to at the Clearwater Marine Aquarium. The animals are too weak
to swim or even lift their heads.
Virulent algae creates red tide of death
A virulent algae bloom is laying waste to huge expanses of the Gulf.
Scientists are split on why it’s so severe.
BY CARA BUCKLEY
LONGBOAT KEY – The sea looked too beautiful to be a morgue,
stretching outward in undulating molten ripples under the summertime
glare. But here, just outside the mouth of Tampa Bay, signs of
trouble were everywhere.
Seabirds were circling endlessly without dipping. A captain scoured
his scanner and his heart broke, because after hours of boating he
hadn’t come upon a single living fish. On the way back to shore, his
passengers began pointing with one hand and covering their mouths
with the other. A long ribbon of dead horseshoe crabs bobbed before
them, interwoven with dozens of belly-up rotting fish.
”There’s not one living thing out here — nothing,” sighed the
captain, Wayne Genthner.
The only thing I see breaking the surface is dead fish.” The culprit behind this patch of lifelessness is an ocean-borne algae known as red tide, and this summer it has come to redefine life along Florida’s Gulf Coast. The toxic, single-cell algae exists naturally, but scientists are divided over whether humans’ irrepressible urge to pave Florida’s paradise is making this current outbreak worse. Red tide sucks oxygen out of the water, suffocating sea life, and contains poisons that impair the nerves. Eighty-one lumbering sea turtles have been killed by red tide in less than three months, a fourfold increase over the usual amount, and another eight are gravely ill. Last week, the algae bloom was blamed for a newly discovered ”dead zone” off Tampa that extends along 2,000 square miles of ocean floor, a soupy underwater graveyard the size of Delaware filled with dead sponges, sand dollars and reefs. Florida’s red tide is different from the strain, deadly to humans, that ravaged New England’s shellfish beds earlier this summer. Still, people in the Sunshine State are adversely affected in ways both marked and mundane. TOXIN IN THE AIR Eating infested shellfish can trigger vomiting and other unpleasantries. The algae also produces an aerosol-like toxin that irritates throats, bloodies noses and triggers asthma fits. Red tide has forced the cancellation of Little League games and summertime bluegrass concerts, and prompted residents of tony Gasparilla Island to don white surgical masks. During particularly intense blooms, visits to a Sarasota emergency room for pneumonia, bronchitis and respiratory complaints spiked by 50 percent, a University of Miami biologist, Lora Fleming, found. ”When it gets going, everyone is coughing and hacking, everyone’s eyes are watering,” said Debbie Hodges, a toll collector at the Skyway State Fishing Pier near St. Petersburg. She keeps a can of Lysol in her booth to mask the red tide smell. Because this algae strain occurs naturally in the Gulf of Mexico, with reports of its existence dating back 200 years, many scientists and state officials have long characterized its ill effects as lamentable but unavoidable, the price of living along Florida’s left coast. Toxic algae blooms are rare on the Atlantic side, scientists say, because the water is faster running and lower in algae-feeding nutrients. `A SERIOUS EVENT’ ”This is a serious event, that’s without question,” said Cindy Heil, senior research scientist at the Florida Fish and Wildlife Research Institute.
But it’s completely natural, yes.”
Yet the virulence, longevity and breadth of Florida’s bloom this year
has caused other scientists, environmental activists and residents to
question just how natural such an intense red tide could be.
Red tide blooms are usually seasonal, and in Florida typically last
just a few months over the fall. But this year’s red tide bloom began
in January, crested in March, and never died off. It now extends from
north of Tampa south past Sarasota, and will likely push farther
While scientists have been unable to forecast when red tide will
strike, they do know the algae requires a steady diet of the
nutrients nitrogen and phosphorus to live and thrive.
Both are found in abundance in fertilizer, storm runoff and sewage,
fueling speculation that Florida’s explosive growth is more than
partly responsible for the noxious algal blanket currently choking so
much life out of the Gulf.
”The size of the blooms and the length they’re lasting and the
damage they’re doing is far from natural,” said Lori Glenn, chair of
the Sierra Club Calusa Group in Southwest Florida.
I personally think it’s nature gone wild.” SCIENTISTS DISAGREE But even scientists looking at the same data cannot agree whether humankind is making red tide worse. On one side of the debate is Larry Brand, a marine biologist at the University of Miami. After comparing two decades’ worth of data, from the 1950s and the 1990s, Brand concluded that the concentration of the red tide algae in Gulf waters has increased tenfold. Brand also believes the severity of the Gulf’s red tide could be attributed to nutrient overload from the Caloosahatchee and Peace rivers, which both flow into the gulf. The Peace River is rich in phosphates from sediment and mining, and the Caloosahatchee runs from Lake Okeechobee, laced with phosphorus runoff from sugar farms and cattle ranches. But scientist Heil said the data Brand used was inconsistent because sampling techniques differed over time. And Richard Pierce, a senior scientist at Sarasota’s Mote Marine Laboratory, said runoff from the Caloosahatchee and Peace rivers cannot solely explain red tide. The blooms vary in intensity, he noted, with this year’s strain starting 30 miles offshore, far from the mouths of either river. ”There is a serious concern that coastal pollution is enhancing red tides, but it’s not as obvious as people would like to think,” Pierce said.
We need more research to go on.”
Along with its contested origins, another vexing aspect of red tide
is that there is no known way to reverse it. Suggestions have
included infusing the water with ozone, which could kill everything,
or dumping out vats of clay with which the algae could bind.
Scientists worry, predictably, that such cures would prove worse than
the disease. The other surefire red tide killer is hurricanes, hardly
an ideal fix. But even after Hurricane Dennis barreled by in July,
the Gulf Coast’s algal bloom reconfigured.
The one grim certainty is that the effects of this summer’s red tide
will extend well into next year. Oxygen is returning to parts of the
dead zone, but a full recovery could take three years at least.
As red tide toxins accumulate in sea grass, more manatees and turtles
are certain to die.
Fishermen are reeling from revenue losses. Hoteliers fear the stench
of rotting fish, and red tide-related breathing woes could scare
Perhaps more worrisome is the growing belief shared by some
scientists that long-term exposure to toxic algae suppresses the
immune systems of animals and humans alike.
”A lot of scientists attribute this to environmental distress
syndrome,” said Gregory Bossart, a pathologist and researcher at the
Harbor Branch Oceanographic Institution in Fort Pierce.
the oceans as our toilets for centuries. I think now we’re starting
to see the effects of our poor stewardship.”’
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