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NOAA Harmful Algal Bloom Operational Forecast System

Explore: Harmful Algal Blooms

Harmful Algal Blooms (audio podcast)

Center for Operational Oceanographic Products and Services

National Centers for Coastal Ocean Science

Scientists can forecast a harmful algal bloom similar to a hurricane

harmful algal bloom in coastal waters credit: Texas Parks and Wildlife Department

HABs occur when colonies of algae—simple plants that live in the sea and freshwater—grow out of control while producing toxic or harmful effects on people, fish, shellfish, marine animals, and birds. HABs have caused an estimated $1 billion in losses over the last several decades to coastal economies that rely on recreation, tourism, and seafood harvesting (image credit of Texas Parks and Wildlife Department).

NOAA's Harmful Algal Bloom (HAB) Operational Forecast System in the Gulf of Mexico identifies whether or not a bloom of algae is likely to contain a toxic species, where it is, how big it is, where it's headed, and if it could become more severe in the near future. Like a weather forecast, this system provides officials advance warning to test and close beaches and shellfish beds more precisely and for a shorter period of time.

This system relies on satellite imagery, field observations, models, public health reports, and buoy data to provide information on bloom events. Forecasters create a public HAB conditions report using this data and information to provide the likelihood of respiratory irritation impacts to people in the area over the next three to four days.

In addition to the conditions report, NOAA issues a HAB bulletin for federal, state, and local coastal resource managers. The bulletin includes a summary of present bloom conditions and boundaries based on water samples and satellite imagery. It forecasts whether or not conditions are favorable for bloom formation, where the bloom may go, and whether algae concentrations are likely to intensify in the near future.

Expert oceanographers at NOAA analyze available data and models in order to create accurate bulletins. To ensure the highest degree of accuracy, all operational HAB forecasts undergo secondary review prior to dissemination.

The Harmful Algal Bloom Operational Forecast System depends on the dedication, energy, and feedback from individuals at partner agencies and other organizations working on this issue. Blooms of harmful algae are not unique to the Gulf of Mexico, so NOAA continues to work with local agencies in Maine, Massachusetts, Ohio, Washington, Oregon, California, and elsewhere in the U.S. to make new forecasts operational over the next five years.