18-04-2025
Algae popping up in waterways again; why it happens, how to protect yourself, pets from toxins
AUSTIN (KXAN) — Warmer weather in Central Texas usually means a few things: Bluebonnets start blooming, severe weather activity picks up, and algae pops up in waterways. If you're a fan of water-related activities, you should especially be aware of the latter of those Spring occurrences.
While some algae contain toxins that are harmful to people, animals and the environment, not all algal blooms are toxic. A harmful algal bloom occurs in bodies of freshwater when Cyanobacteria, also called blue-green algae, produce toxins.
According to the city of Austin, Lady Bird Lake experienced a harmful algal bloom in 2019, which sickened and killed several dogs. There have been harmful blooms on the lake and other local bodies of water every year since then.
Austin pilot program treats algae on Lady Bird Lake
Austin Watershed posted on Facebook Thursday, cautioning people about the presence of algae.
'We are seeing a lot of algae at Red Bud Isle that could be toxic. It may be present in other places as well. Please treat all algae like it may be toxic,' the post said.
Red Bud Isle is a popular leash-free dog park on Lady Bird Lake, just below the Lake Austin dam. While canoes, kayaks and similar watercraft can be used on Lady Bird Lake, swimming is not allowed.
What's in the water? Toxic algae thriving
Austin Watershed recommended that people avoid contact with algae, not drink water from the lake, rinse off after contact with water, and not allow dogs to lick their fur before rinsing them off (if they've been in contact with lake water).
Harmful algal blooms can cause a variety of mild to life-threatening illnesses in people in animals, according to the Centers for Disease Control and Prevention. Signs and symptoms can vary based on the toxin and exposure.
Illnesses caused by toxic algae can happen if a person or animal ingests toxins, comes in direct contact with toxins through the skin or eyes, or inhales gases such as hydrogen sulfide and methane that are produced by cyanobacteria.
Symptoms can include but are not limited to:
Headache or fever
Nausea, vomiting, or diarrhea
Acute hepatitis or jaundice
Blood in urine or diarrhea
Numbness
Burning sensation
Drowsiness
Salivation
Speech disturbances
Allergic dermatitis, including rash, itching, or blisters
Conjunctivitis
Respiratory irritation
If you, a family member or a pet has sudden, unexplained symptoms after swimming or being exposed to a body of water, contact your medical provider, veterinarian or the Texas Poison Control Center at 1-800-222-1222.
Austin Public Health also has a harmful algal bloom suspected illness reporting form, available in English and Spanish.
While algae are naturally occurring and an important part of aquatic ecosystems, some species under some conditions can produce toxins, according to the United States Environmental Protection Agency (EPA).
In Austin, waterways are frequently tested for several types of algae, but cyanobacteria, or blue-green algae, are the most common. When they form mats big enough to see, they usually look like dark green, slimy blobs, according to the city. Blue-green algae are often mixed in with other types of algae.
The city said it is not aware of any human or pet health problems from harmful algae in Austin before 2019. The city noted that zebra mussels, flooding during the fall of 2018, and climate change are potential contributing factors to the harmful algae bloom that occurred in 2019.
The EPA noted online that climate change has effects on bodies of water that might cause algal blooms to become more severe and to occur more often in more water bodies. Those effects are predicted to be exacerbated in the future, according to the EPA.
More information about harmful algae and algae mitigation can be found on the city of Austin's website.
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