With Murky Water And Manatee Deaths, Lagoon Languishes
Thursday, September 26, 2013
Something is wrong in Florida's Indian River Lagoon.
Over the past year, record numbers of dolphins, manatees and pelicans have turned up dead in the 150-mile-long estuary that runs along Florida's Atlantic Coast. Bouts of algal blooms have flourished in the waters. All the signs point to an ecosystem that is seriously out of balance. The crisis has mobilized scientists, residents and elected officials in Florida.
An Ailing Lagoon
Florida has gotten a lot of rain this year. While that's good in some ways, for the lagoon it spells trouble. As Lake Okeechobee has risen, water managers have diverted much of the excess flow down canals, taking it West to the Gulf of Mexico -- and east to the Atlantic.
Dennis Hanisak of the Harbor Branch Oceanographic Institute in Fort Pierce uses a small pontoon boat to check on a network of monitors that keep track of the lagoon's vital signs -- temperature, pH, salinity, oxygen levels and other factors like turbidity and water color.
Along the lower end of the Indian River, Hanisak says, the lagoon is looking sick. "This year with the Lake Okeechobee discharges," he says, "we see very low salinities, we see very high nutrients. We see very high water color. We see high turbidity."
The fresh water lowers the salinity in the lagoon and carries silt and other solids that make the water murky. Perhaps most critically, water from Lake Okeechobee carries high levels of nitrogen and phosphorus, pollutants that Hanisak says have had a big impact.
A Plague Of Algae
Because of the release of water from Lake Okeechobee, the lower end of Indian River Lagoon this summer has been beset by large algae blooms, some toxic. They've killed off delicate sea grass beds and dealt a blow to a regional economy that depends on the lagoon for recreation and commercial fishing.
It's the third year in a row of bad news in the lagoon. In 2011, the northern end of Indian River was devastated by an algae superbloom, an event that was followed last year by a different outbreak.
"We have reached a tipping point in the Indian River lagoon now," says Brian Lapointe, a research professor at Harbor Branch who has investigated the algal blooms and the death of marine mammals in the lagoon. In the past year, more than 60 dolphins and 120 manatees have died. At least with the manatee deaths, he says, the cause is clear.
As sea grass has died, Lapointe says, manatees have turned to eating a type of macro algae, a red seaweed that has become toxic with the lagoon's changing chemistry. "This is what they're left with to eat. And they're eating a lot of this -- 40, 50 pounds a day or more," he says.
The algae blooms, along with the manatee and dolphin deaths, have led many in Florida -- including politicians -- to declare a crisis. Florida's Senate formed a select committee to search for answers.
"We are past the time for talking and power points and deliberations. We are here to find some short-term solutions to the current environmental crisis," said Sen. Joe Negron, who chaired a recent hearing in Stuart, a town on the St. Lucie estuary.
Speaker after speaker told the committee that there are no short-term solutions. The Army Corps of Engineers, which maintains the levees and water level in Lake Okeechobee, says releases of polluted water from the lake are unavoidable. Because of all the rain, they're necessary to avoid a possible catastrophic breach of the lake's levees.
The only real answer, scientists say, is to stop draining Lake Okeechobee into the Indian River lagoon and restore its natural flow through the Everglades to the south. That's a long-term solution still many years and billions of dollars away.
Septic Tanks Galore
But stopping the water releases from the lake would still address only part of the problem in the lagoon. A larger issue -- one that may be even harder to deal with -- is septic systems. In three counties on the lagoon, Lapointe told the committee, there are 237,000 septic tanks.
"Do the math. Over 1 million kilograms of nitrogen a year are going toward the Indian River lagoon from septic tanks alone," he said.
Crisis or not, there's little political will in Florida to begin requiring communities to move residents off septic tanks.
In his 40 years of work on the Indian River lagoon, Lapointe has seen similar crises come and go. A few years of drought may ease the algae blooms. Politicians may lose interest. But, he says, if the lagoon's health has indeed reached a tipping point, the way that communities and elected officials react this time will have long-term consequences for the river.
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