How Can An Algal Bloom Be Harmful?

We’re in the middle of our Watershed Pollution Prevention class, and the term “Harmful Algal Bloom” has come up a few times. HAB’s don’t get their own lesson, so let’s talk a bit about what they are!

What’s an HAB?

HAB’s are classified when the bloom contains visible areas of blue-green algae, or cyanobacteria. That being said, cyanobacteria can vary in color, ranging from bright green, blue/green, and brown.

Small amounts of cyanobacteria exist is healthy waterways, but can grow out of control under these conditions:

• Excess nutrients

• Warm temperatures

• Low winds

• Lots of sunlight

You might notice it has streaks or looks like spilled paint.

Is all algae bad?

Not all algae is harmful. Like we learned in the Live Food lesson, algae is an important part of the food chain (Department of Environmental Conservation). Green algae might float, bubble, look silky, or form thick rafts, but they don’t produce cyanobacteria.

How can HABs harm humans?

HABs can harm people when they come in contact with it by touching it or ingesting it. You may notice fever-like symptoms, nausea/vomiting, diarrhea, or rashes (EPA).

How can HABs harm pets and wildlife?

Harmful cells from HABs can stick to animal fur and can be ingested when the animal cleans itself. Give your pet a bath with clean water and seek veterinarian advice if your pet shows signs of distress after a potential exposure (DEC). Symptoms of HABs exposure for dogs include:

• Excessive salivation or drooling

• Disorientation or inactivity

• Elevated heart rate and difficulty breathing

HABs can also impact entire ecosystems! Think about our trout for instance. HABs deplete oxygen (which we know our trout need!) and can kill crustaceans (like our daphnia) and small fish (like our trout). What happens to our predators, like birds or larger fish, if the bottom of the food chain collapses?

How can we prevent HABs?

The general public, especially those who live on the water, can do their part to reduce the likelihood of algae blooms by reducing the addition of nutrients (phosphorus and nitrogen) to waterbodies. The amount of nutrients can be decreased by:

• Limiting lawn fertilization

• Scoop the (dog) poop

• Maintaining septic tanks

• Installing and maintaining shoreline buffers