AUSTIN (KXAN) — The Austin Watershed Protection Department has started to monitor Lady Bird Lake for toxic blue-green algae on a weekly basis as temperatures soar to triple digits in the area.

Last year, when harmful algae called cyanobacteria produced toxins and created algae blooms, they city said at least five dogs died after swimming in that water.

Staff collected samples Thursday from Red Bud Isle, Vic Mathias Shores and Festival Beach.

Brent Bellinger, Ph.D, Environmental Scientist Senior at the Watershed Protection Department, told KXAN they already detected a low level presence of the harmful algae near Red Bud Isle, a popular off-leash spot.

The algae thrives in stagnant areas when water temperatures rise.

“We’re still putting all those puzzle pieces together. It’s a it’s a complicated story,” explained Bellinger. “In general, cyanobacteria seem to do really well when water temperatures exceed 25, 27, 30 degrees centigrade.”

That’s 77, 80, 86 degrees Fahrenheit.

Bellinger added, “Cyanobacteria really prefer an undisturbed system, so they want kind of stagnant waters where they can do their thing. They’re not constantly being stirred up or flushed away.”

He said the presence of phosphorus and nitrogen appears to also create an environment in which this algae thrives. “Of course, these are very common pollutants, you know, in many urban waterways and systems,” Bellinger said.

Blue-green algae is particularly harmful to dogs.

“The issue is that they’re drinking right from the top, the way they lap up the water, they’re drinking right off the top of the surface, and that’s where you have the highest concentration,” said John Higley, CEO of EQO.

Higley said in Austin’s situation, zebra mussels is likely playing a role.

“Each one of those guys filters about 1,000 litres of water a day,” he said. “They’ll eat up all the primary food sources for the other things that eat up all the good algae and create a perfect niche for the cyanobacteria, that toxic algae, to grow. And they don’t eat the toxic algae, they reject it, spit it out.”

When the Watershed Protection Department was asked about this, Bellinger responded, “Can’t discount it. Can’t say that’s a smoking gun, but it’s a very intriguing angle.”

The city is waiting for results to come back to see algae is present in more areas of Lady Bird Lake. Those results should be available next week, and a summary will be posted on the city’s website.

Right now, the advice is to avoid stagnant water.

“It’s safest where you can find some good cool water where it’s flowing,” Bellinger said.

Symptoms of exposure to blue-green algae in dogs include:

  • Excessive drooling, vomiting and diarrhea
  • Foaming at the mouth
  • Jaundice and hepatomegaly
  • Blood in urine or dark urine
  • Stumbling
  • Loss of appetite
  • Photosensitization in recovering animals
  • Abdominal tenderness
  • Progression of muscle twitches
  • Respiratory paralysis

Owners should take their dogs to a veterinarian immediately if they see any of the symptoms.

Signs are at six places around the lake, and if higher levels of algae are detected, the department says it will put more signs up.