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Harmful Algal Blooms (HABs)
Algae are small photosynthetic organisms found in almost every environment on Earth. Under the right conditions, such as high nutrients and sunlight, algae can grow rapidly and "bloom." Algal blooms often accumulate on the surface of water bodies, giving the water a green, brown, or red appearance.
A Harmful Algal Bloom (HAB) is a bloom of certain types of algal species that produce toxins as it blooms or dies. These toxins may harm wildlife and humans when ingested or inhaled. In the Great Lakes, the algal species that are commonly associated with HABs are the cyanobacteria or blue-green algae known as Microcystis.
- What effects do HABs have on people and wildlife?
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HABs can cause illness and death in humans, pets, and wildlife. Symptoms include:
- Acute liver failure
- Cardiac or respiratory failure
- Muscle cramps
- Nausea and vomiting
- Paralysis
- Skin rash
- Twitching
- What factors affect HABs?
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Nutrients, such as nitrogen and phosphorus, can contribute to blooms. Sources of nutrients include agricultural activities, application of lawn fertilizers, wastewater treatment facilities, septic tanks, sewer overflows, and runoff. Warm surface water temperatures can also contribute to blooms.
- Do HABs occur in the Great Lakes?
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Yes. The Great Lakes have a history of HABs, particularly in warm, shallow areas such as Saginaw Bay and western Lake Erie. Scientists have attributed this latest resurgence of HABs to the invasion of zebra and quagga mussels.
- What can I do about HABs?
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- When you see an algal bloom, the safest course of action to take is to stay away from the water. Also, keep pets away from the water as the toxins can also harm them.
- Remember that you can't always see, taste, or smell harmful algae. Rinse yourself and your pets off after swimming. Do not drink lake or river water. Bring water for your pets; drinking untreated water may also harm them.
- Obey beach closures and advisories.
- Report suspected blooms to your local health department. You can contact the Monroe County Health Department at 734-240-7900 or to find more information about blooms, see Harmful Algal Blooms.