Can we clean up, stop, or end harmful algal blooms?

Harmful algal blooms (HABs) occur when algae produce toxic or harmful effects on people, fish, shellfish, marine mammals, birds, or other aquatic organisms. Blooms occur in marine and freshwater environments throughout the world, with damaging ecological, social, and economic effects. So why can’t we clean up the algae and take care of this problem? Unfortunately, the answer is not so simple. Harmful algal blooms are a natural process. There are records of HABs from early European colonists arriving to Florida in the 1500s. However, research points to an increase in the frequency and intensity of algal blooms in modern times due to environmental changes caused by humans.

There are many examples of human activities that contribute to HABs: runoff from agriculture, dissolved chemicals introduced into water supplies via rainfall or irrigation, and effluent from sewage treatment plants all contribute to excess amounts of nutrients in our waterways. These nutrients are food for algae. In housing developments, for example, retention ponds are a common place to see freshwater HABs. All this runoff ends up in the water system, eventually making its way to the ocean.

One of the primary missions of NOAA's National Centers for Coastal Ocean Science is to empower communities to take action on HAB issues by developing detection tools and forecasts. NCCOS is involved in mitigating harmful algal blooms in a number of different ways and through several legislative measures. For example, the Harmful Algal Bloom Hypoxia Research and Control Act provides NOAA with a legal mandate to study HABs, to mitigate their effects, and to provide early warning for when and where blooms will occur. NOAA partners with other organizations throughout the country, as well, to support research through four national competitive funding programs:

1. The Ecology and Oceanography of Harmful Algal Blooms program funds research to understand the causes and impacts of HABs and their toxins.

2. The Monitoring and Event Response for Harmful Algal Blooms program focuses on developing reliable detection technologies for HAB cells and toxins, and improving monitoring strategies and forecast models to enhance early warning capabilities.

3. The Prevention, Control and Mitigation of Harmful Algal Blooms program focuses on research and development of promising technologies for preventing, controlling, or mitigating HABs and their impacts.

4. The Social, Cultural, and Economic Assessment of Harmful Algal Blooms program focuses on assessing impacts of bloom events on coastal economies and societies, and the costs and benefits of mitigation strategies to aid managers in devising cost-effective management strategies.

Harmful algal bloom resources, frequently asked questions, and regional information are available via the National Ocean Service HAB portal.