Tag Archive for: water turn color

Pop Quiz: What Made This Water Turn Color?

West Fork Sand Pit photographed on 2/13/2020
Same pool shown within a larger context.

Multiple Choice Quiz

So what made this water turn color? This is definitely a hard one:

  1. TACA is promoting Sherwin-Williams.
  2. It’s a Slurpee® and snow cone waste pit.
  3. All the left-over food coloring that Randall’s couldn’t sell at 95%-off wound up here.
  4. The country of Gabon is advertising tourism.
  5. Cyanobacteria are taking over the pit.

And The Answer Is…

If you guessed D, you at least get points for knowing your flags. Gabon’s colors are blue, green and yellow. But you also guessed wrong. Gabon wouldn’t stoop this low.

The correct answer is E – cyanobacteria.

About Cyanobacteria

According to the TCEQ and Denise Wade at Harris County Flood Control, blue-green algae, also known as cyanobacteria, naturally occur in bodies of water. Blue-green algae have the potential to grow throughout the year. Blooms are seen more frequently during summer months in warm, stagnant, nutrient-rich water. Blue-green algae blooms can appear as in the photos above or even emerald green, blue green, pea green, red-brown, or white.

“The algae sometimes attach to sediment or plants at the bottom of a water source. Wind can even blow the algae onto soil surrounding the water source. If there has been a blue-green algae bloom, but it has collapsed (decayed), there may still be algal toxins in the water,” said Wade.


But it looks so pretty! Especially the blue part. Kind of reminds you of Cancun (if not Gabon). Don’t be fooled!

Cyanobacteria can be very dangerous. The World Health Organization has documented acute impacts to humans from cyanobacteria from the US and around the world as far back as 1890. While most human health impacts have resulted from ingestion, illnesses have also been attributed to swimming in cyanobacteria infested waters. Exposure to toxic cyanobacteria scums may cause various symptoms, including nausea, vomiting, diarrhea, mild fever, skin rashes, eye and nose irritations, numbness and general malaise. Some studies even suggest cyanobacteria may be linked to more serious illnesses.

NOAA warns that people often get sick by eating shellfish containing toxins produced by these algae if found in a larger water body; obviously, shellfish aren’t found in sand pits. However, the algae, they say, are often found in stagnant water which is found in sand pits.

The airborne toxins, says NOAA, may cause breathing problems and, in some cases, trigger asthma attacks in susceptible individuals.

According to Robin Cypher of the TCEQ, “Some strains of cyanobacteria can produce toxins (cyanotoxins) in concentrations that are harmful to humans, pets, fish, and wildlife. Cyanobacterial blooms can also produce secondary compounds which can cause taste-and-odor problems in public water systems.”

 “Cyanobacteria are a group of photosynthetic bacteria found in surface waters throughout the country,” says Cypher. “Similar to algae, cyanobacteria can rapidly multiply forming thick blooms, especially in warm, nutrient-rich waters.”

How to Report Cyanobacteria Blooms and Learn More

Sightings of fish kills or suspected harmful blooms can be reported to Texas Parks and Wildlife Department’s 24-hour communications center at 512-389-4848.

Sources of information about harmful algal blooms include:

TPWD Harmful Algal Blooms

USGS Harmful Algal Bloom (HAB) Science in Texas

EPA Cyanobacterial Harmful Algal Blooms (CyanoHABs) in Water Bodies

Safety Warnings

If you’re out hiking in the woods and you see such water:

  • Do not wade or swim in the water, especially near surface blooms.
  • Do not drink the water; avoid drawing lake water.
  • Do not let pets or livestock into or near the water; dogs are especially vulnerable to toxic cyanobacteria.

Now if someone asks you, “What made that water turn color,” you will know. And more important, you can warn them.

Posted by Bob Rehak on 2/24/2020 based on information from Harris County Flood Control

909 Days after Hurricane Harvey