Algae Alert by Laura French
The dangers of blue-green algae to humans and pets are serious enough for the Minnesota Pollution Control Agency (MPCA) to devote a Web page to it. More accurately called “cyanobacteria,” the algae create toxins that damage the liver and may be cancer-causing.

Mild symptoms include muscle pain, rashes, vomiting and diarrhea. Extreme exposure can cause convulsions, paralysis and respiratory failure. In 2007, at least four dogs died in Minnesota from drinking water that contained blue-green algae, according to the MPCA.

The good news is that blue-green algae are highly visible--unlike the larvae that cause “swimmers itch.” The most common descriptions of water with toxic levels of blue-green algae are “like pea soup” or “like someone spilled green paint.” Algae blooms often come with a foul odor, as well.

The problem is that Minnesota lakes contain lots of algae that are not cyanobacteria. Even when cyanobacteria are present in the water, they aren’t always toxic. That only sure way to avoid the problem is to stay out of the lake—something that Minnesota dogs and humans are not likely to do.

Generally speaking, toxic algae blooms are more likely to occur in late summer and in hot, still weather. Those are the conditions that enable cyanobacteria to crowd out other algae and for the toxins to accumulate. While winds can sometimes cause the toxins to dissipate, at other times the winds can cause the algae to build up along the shore, making the problem worse.

While blue-green algae are toxic to humans, we’re less likely to wade in or drink water that’s covered with smelly, scummy algae. Many dogs don’t exhibit that kind of delicacy. On a hot day, they’re likely to turn to any water source they can find. Hunting dogs rank high on the list of blue-green algae fatalities, perhaps because they run free for long periods of time, working up a thirst. They may also find small, algae-covered ponds while out of sight of their owners.

The cool temperatures of spring and early summer this year may have reduced the risk of blue-green algae blooms, experts say. However, the risk can’t be eliminated. Dog owners should do what they can to keep their pets safe.

• Bring along your own supply of drinking water on hot days. There are easy-to-carry, collapsible water dishes available.

• Know the difference between blue-green algae and other common plants found in lakes and ponds, like duckweed. The MPCA website has a page of photos for comparison.

• Wash your pet after it’s been in a lake or pond. Algae can cause skin problems even if they aren’t ingested.

• If you think your pet has ingested algae, call a vet immediately. Some toxins can cause illness in as little as an hour; others can take up to 24 hours.

Finally, for the sake of everyone’s pets, minimize the amount of fertilizer run-off from your lawns and fields. The nutrients that humans have added to the water supply are making algae problems worse.

For more information on how to recognize and avoid blue-green algae, visit the MPCA Website.

Laura French is a freelance writer who lives in Roseville with three cats — Gracie, Tennessee Tuxedo and his pal Chumley, and Sofie, whose breed(s) will forever remain a mystery.