Florida's massive algae blooms have captured plenty of attention as the smelly, green goop killed large numbers of fish, caused the closure of beaches and prompted the Florida governor to declare a state of emergency in late June.
Could this happen in Louisiana?
A plume of sediment-laden river water is slowly spreading along the southern reaches of Lake…
“We do see (algae blooms) a lot, but they don’t get as much attention,” said Sibel Bargu Ates, an associate professor with the LSU Department of Oceanography and Coastal Sciences.
One reason is that there are relatively few public beaches in Louisiana where people can see and turn in reports of suffering marine life, such as the toxic effects that result from dead sea lions in California. Those public reports prompt the state to send people to test for possible algae blooms.
In addition, there is no systematic statewide monitoring program for algae blooms, Ates said, though testing is done when a problem pops up.
“We just don’t know if it’s happening or not,” she said.
The state doesn’t test for a wide range of algae, but it does have a program to test for “red tide” algal blooms that can force the closure of oyster beds if the levels get too high.
There are 67 sites along the Louisiana coast where the state conducts tests about four times a month, said Gordon LeBlanc, program administrator for the state Department of Health's Molluscan Shellfish Program.
Texas and Mississippi both have testing programs as well, so if a problem is seen in those states, Louisiana knows to start testing more often.
Oyster bed closures because of algae have been rare, with the last two occurring in 1996 -- a four-month closure and an almost two-month closure in Breton Sound, LeBlanc said.
Ates said her research has shown that hazardous algae blooms usually occur in the early spring, but they don’t seem to be accompanied by large numbers of animal deaths. The main victim would be dolphins, although the algae would not be likely to kill the animals, and such deaths are not something the public would see.
“It’s just not the nature of our coastline,” Ates said.
In other areas where there are toxic algae blooms, people walking along the beach might start to cough or have watery eyes. Those reactions are caused by a neurotoxin that makes the muscles in the eyes and lungs spasm, said Reagan Errera, a professor in the LSU School of Renewable Natural Resources.
Algae blooms, similar to the ones occurring in Florida, do occur in freshwater areas in Louisiana, including in Lake Pontchartrain and Breton Sound.
Each aquatic system is unique in what it required for an algae bloom to occur, Ates said.
In Lake Pontchartrain, the algae blooms primarily depend upon the amount of river flow from the north shore into the lake, she said. These toxic blooms require warm temperatures, calm waters and a certain combination of nutrients to feed the growth.
Not all algae blooms are toxic, and there is a dizzying array of both freshwater and saltwater algae in Louisiana and along the Gulf coast -- some being an important part of the food chain.
For those algae that do produce a toxic effect, the impacts can be different depending on the type. Some irritate the skin, while others are neurotoxins and still others can impact the liver.
“It all depends on what type we look at,” Errera said.
The saltwater types of algae do occur in Louisiana, but they don’t reach the scale seen in other areas because the outflow of the Mississippi River brings a lot of fresh water into parts of the system.
In Florida, all the components for algae blooms are present in the summer: low water flow, high nutrient content and warm waters.
“This happens in Lake Erie almost every summer,” she said.
Even though some of these toxins can accumulate in sea life, Ates said her research didn’t find any hospital reports that would point to people getting ill through seafood consumption or contact.
“It’s tricky to see if people are getting sick,” she said. “And the algae isn’t always there.”