Harmful Algal Blooms

Algae are an important part of our environment and food web, but under certain conditions, some can be harmful to people, pets and livestock. The important thing to know is that the algae you hear about in the news associated with harmful algal blooms is not actually algae at all. It is actually a bacteria, cyanobacteria, that acts like algae as it needs sunlight with nutrients to grow.

Cyanobacteria can occur in fresh or marine waters. If the conditions are right, including the presence of excess nutrients and sunlight, these cyanobacteria can grow out of control in water bodies; this called a bloom. This is when the “harmfulness” of the cyanobacteria can occur, leading to the name harmful algal blooms, or HABs.

What Is a Bloom?

Blooms can occur when conditions are right for the cyanobacteria to grow in large numbers. Blooms typically occur when there are excess nutrients, like phosphorus or nitrogen, in the water. Nutrients can enter the water through runoff from farm fields that have had too much fertilizer applied to them; runoff from areas that have malfunction septic systems; or even general land runoff. The cyanobacteria also need sunlight and warm, mostly stagnant waters. The warmer the water in the lake, pond or reservoir, the more the cyanobacteria thrive in it. For Lake Erie, blooms are typically seen from mid- to late July to the end of September.

Large-scale blooms occur in the western basin of Lake Erie. The blooms can become so large that they can be seen from a satellite in space. The blooms we would get in our part of Lake Erie tend to be more localized than large scale; however, that could change in the future if water temperatures warm earlier in the summer and stay warmer longer in the season.

What Do Blooms Look Like?

Harmful algal blooms can look like a few different things. They can look like someone spilled latex paint on the surface of the water, ranging in colors like blue, green, white, and even brown or red. Blooms also can look like pea soup, or like scum, mats or films. Blooms also might have little balls of green in the water below the surface. The water can also look discolored or have colored streaks in it.

What Is Being Done?

In 2014, the Erie County Department of Health formed a HAB task force with the Pennsylvania Department of Environmental Protection, the Pennsylvania Department of Conservation and Natural Resources, the Pennsylvania Sea Grant and the Regional Science Consortium, in order to create a strategy for how to respond to blooms. The task force educates the public about what to look for during summer trips to Lake Erie, and also conducts testing from May or June until late October for the toxins that cyanobacteria produce. This testing is conducted by the Regional Science Consortium through grant funding.

The toxins tested for by the Regional Science Consortium are microcystins, on a weekly basis; cylindrospermopsin, twice a month; and anatoxin-a and saxitoxin, once a month each. Any time a toxin exceeds the recommended threshold, the appropriate signage is posted to alert the public.

Why Are Cyanobacteria Harmful?

Cyanobacteria can release toxins into the water that can have a wide range of effects on people, pets and livestock. These toxins can either be in the cells of the cyanobacteria or in the water. Unfortunately, scientist do not know all the reasons cyanobacteria release the toxins, but they do know that if the cyanobacteria is damaged it can release toxins.

Human illnesses and symptoms can vary as it depends on length of exposure, how exposure occurred, and which toxin is involved. The following is a list of possible symptoms in humans, but is not an all-encompassing list.

  • Skin, eye, nose, throat or respiratory irritation
  • Abdominal pain
  • Nausea or vomiting
  • Diarrhea
  • Headache
  • Numbness, tingling or burning
  • Drowsiness

Animal illnesses and symptoms can vary as it depends on length of exposure, how exposure occurred and which toxin is involved. The following is a list of possible symptoms in animals, but is not an all-encompassing list.

  • Excessive salivation
  • Vomiting
  • Fatigue
  • Staggered walking
  • Loss of appetite
  • Difficulty breathing
  • Convulsions
  • Liver failure
  • Death

Why Are Warnings Posted For Dogs?

The threshold for dogs is much lower than the threshold for people, and signs are posted in areas where people typically take their dogs for a swim. The reason the threshold for dogs is lower is because when they swim, they tend to ingest the water. They also lick their fur when they get out of the water, and they have tendencies to eat the algal mats. Because of this behavior, dogs are more susceptible to receiving a higher dose of toxins than people. This is also why it is recommended to wash your dog off as soon as possible after exiting the water.

What About Risks For People?

It is important to remember that dogs have certain behaviors around water that people do not do. So even though adults are not ingesting the water in large quantities or licking the water off of themselves like dogs do, there could be a risk of having symptoms after contact with the water for us. It is also recommended that you keep an eye on small children, as they could sometimes accidentally ingest water while playing in it. If there is a concern that small children could ingest the water, it is recommended that you keep them out of the water as well.

What Should I Do If I See Symptoms?

For humans, it is recommended to contact and see your physician or go to the emergency room if the symptoms are severe. Give the doctor as much information about the symptoms and where the contact with recreational open waters occurred.

For pets or livestock, have a veterinarian see the animal as soon as you can. Symptoms can progress in animals very quickly.

How Do I Protect My Family and Pets?

  • Visit our interactive online map to see what locations are tested and what current advisory is posted.
  • Do not enter a lake, river or creek adjacent to a sign that is posted for HABs.
  • Know what a bloom looks like and avoid bodies of water that smell bad, look discolored, have foam, scum or algal mats, or have dead fish/animals in the area of the shoreline.
  • Keep pets and livestock out of water that is posted for a HAB or that appears have signs of a bloom.
  • Wash off with soap and water any people or animals that have been in contact with waters that may have a bloom.
  • Do not drink or use water with signs of HABs.
  • Do not allow pets or children to play or eat algal mats or to drink the water.
  • Contact your doctor or veterinarian if you, your family, or your pet exhibits symptoms.
  • If in doubt, stay out.

Where to Learn More

For more information, please visit the following websites: