Harmful Algal Blooms


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    Harmful Algal Blooms

    You may have heard of the Harmful Algal Blooms (HABs) that have occured in Utah Lake. A HAB or cyanobloom is the term for the explosive growth of certain species of photosynthetic cyanobacteria which are known to release toxins into the water. Cyanobacteria are naturally part of the algae community of lakes and ponds, however when conditions are favorable, large, rapid growth can occur. 

    dock habWHAT CAUSES BLOOMS? 

    While blooms can happen naturally in pristine mountain lakes and impaired urban waterways, certain conditions (i.e. usually warmer waters and high concentrations of phosphorus and nitrogen) can increase the likelihood of blooms. As global temperatures increase, scientists have noticed blooms at an increasing frequency.

    Nitrogen and phosphorus are common pollutants that can come from sewage treatment plants, erosion and urban and agricultural runoff. Proper land management and the investment in new technologies to treat wastewater can reduce the likelihood of blooms.


    hab signCertain species of cyanobacteria, (including Dolichospermum, Aphanizomenon, Cylindrospermopsis, Microsystis and Ocillatoria) can release toxins into the water which can be dangerous to humans and pets. Some neurotoxins can cause immediate sickness or death while others can lead to long-term kidney or liver damage. If you notice a bloom, keep yourself and pets out of the water.



    • Reduce the amount of fertilizer use on your lawn

    • Use phosphorus-free fertilizer when possible

    • Fix leaking septic systems

    • Use phosphorus-free detergents in dishwashers

    • Keep yard debris such as leaves or grass clippings from washing into storm drains

    • Pick up pet waste



    Utah Water Watch volunteers are trained to monitor for, sample and analyze potential harmful algal blooms.

    Introductory monitoring:

    Become aware of the presence of potential cyanobacteria and learn collection and identification methods.

    Advanced  monitoring:

    Volunteers can work with NOAA to monitor a water body 2/x a month for the presence of 5 target cyanobacteria types.

    Find out more at Utah Water Watch.


    What do they look like?:

    Cyanobacteria blooms can be differentiated from blooms of ordinary green algae or growths of duckweed relatively easily.  See some examples below.

     Green Algae


    Not cyanobacteria:

    Green algae tends to be stringy, bubbly and often floats in blobs on the surface.












    Duckweed are tiny floating water plants, look closely and you will see small leaves and roots.






    Cyanobacteria in Mantua




    Cyanobacteria blooms often look like green pea soup, spilled paint, green blobs or streaks.







    Want to participate in Utah Water Watch’s Harmful Algal Bloom monitoring program? Email waterquality@usu.edu or call the Water Quality Extension at (435) 797-2580.

    Additional Resources:

    Learn about HAB's in Utah, and what's being done to prevent them at the DWQ's site.

    For a more comprehensive guide to harmful algal blooms from the USGS click here.

    Learn more about cyanotoxins from the EPA.

    To see what different Cyanobacteria look like under the microscope click here.