Excessive rainfall caused by El Nino increases the risk of toxic algal ... - Houma Courier

Increased runoff from heavy rains could lead to toxic algal blooms, experts warn.

Weather patterns brought on by El Nino increased rainfall, washing nitrogen and phosphorus into bodies of water. These nutrients foster the growth of algae that are poisonous to humans and pets. The blooms appear as pond scum, a slime that rests on top of the water, National Oceanic and Atmospheric Agency Oceanographer Rick Stumpf said. If you see it, keep pets and people away from it.

"If you see scum, stay out of the water," he said. "When it's scum it's concentrated up to 100 times, so that's a lot of toxin."

He said dogs are particularly in danger because when they swim in it their mouths are open, close to the surface. Not only that, but when they exit the water, the scum will still be trapped in their fur. Each year the toxic algae claims the lives of pets, he said, though he estimated that thankfully it's less than 10 a year.

El Nino is a weather event that causes warmer than average sea surface temperatures in the central and eastern pacific near the equator. The event happens every two to seven years.

The toxic algae comes in numerous species that can grow in both fresh and saltwater. The toxins come in many varieties as well. Some are neurotoxins, while others are hepatotoxins. The toxins can lead to rashes if they contact skin, organ failure if ingested, and some, such as the infamous Red Tide, can release their toxins into the air, affecting eyes and lungs.

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Microcystin, a hepatotoxin found in the freshwater blue-green algae, can cause symptoms such as nausea and vomiting if ingested, and rash or hay fever if touched or inhaled. Drinking water with the toxins can cause long-term liver disease.

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Louisiana Department of Public Health, LSU Ag Center and the Center for Disease Control and Prevention have put out warnings about the algaes. Their advice mostly follows that of Stumpf, but also suggest contacting the local government if you suspect a bloom to ensure drinking water is safe.

The algae are semi-plant and semi-bacteria, and enjoy warm, high nutrient, low-moving water. Terrebonne and Lafourche are mostly shielded from this thanks to the constant flow of the bayous, Barataria Terrebonne National Estuary Program Scientist Andrew Barron said, but he warns the parishes aren't immune to a potential outbreak.

BTNEP is working with the Water Institute on research to predict potential blooms in the area, but Barron said he couldn't go into more details until the research is complete. The study is likely to finish within the next year, he said.

"We're going to be able to do a better job at identifying these sorts of things in the coastal waters," he said. "It's kind of a toolkit to be able to predict a harmful algal event is going to occur… it's kind of like predicting the weather."

Stumpf explained that the algae are phytoplankton, some of the oldest photosynthesizers ever documented. "There's evidence of them going back 3 billion years," he said.

The toxins in the varying species of algae evolved parallel to one another, he said. Some algae evolved to have the poison as a defensive measure against its predators, while others evolved the poisons as a byproduct to adapt to environmental stressors.