# Center for Sponsored Coastal Ocean Research (CSCOR) Science Serving Coastal Communities



## Harmful Algal Blooms

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# Overview

Click Here for information about th e West Coast HAB Summit 

# Why is this issue important? A small percentage of algal species cause harm to hu mans and the environment through toxin production or excessive growth—these are the harmful algae and they include both microalgae (microscopic, single celled organisms) and macroalgae (seaweeds). Some harmful algae produce potent toxins which cause illness or death in humans and marine organisms—fish, seabirds, ma natees, sea lions, turtles, and dolphins are some commonly affected animals. Other types of harmful al gae are nontoxic to humans but cause harm to fish and invertebrates by damaging or clogging their gills or by forming such large blooms that the death and subsequent decay of the algae lead to hypoxia (oxygen depletion) in the bottom waters of marine environments. Dense blooms can also block sunlig ht for beneficial alga e and seagrasses. HABs can have major negative impacts on local econom ies, and a recent conservative assessment estimates that HABs occurring in marine waters alone have an average annual impact of $82 million dollars in the U.S. All U.S. coastal states have experienced HABs over the last decade, and new species have emerged in some locations that were not previously known to have problems. HABs occur naturally, but human activities that disturb ecosystems in the form of increased nutrient loadings and pollution, food web alterations, introduced species, and water flow modifications have been linked to the increased occurrence of some HABs.

 Economic Impacts of HABs

 Human Dimensions of HABs 

# How are we addressing this issue? NOAA’s goal is to provide tools to prevent, control, or mitigate the occurrence of HABs and their impacts. In the 10 years following the passage of the original Harmful Algal Bloom and Hypoxia Research and Control Act ( HABHRCA ), CSCOR HAB Programs have made signif icant advances that have improved HAB management. More accurate and efficient tool s for detecting cells and toxins, early warning of toxic blooms, better predictions of when and where the blooms will move, and partnerships developed that allow for more effective response are just a few examples of how CSCOR-supported HAB research has benefited society. Because the challenges for managing HABs differ amon g regions of the country, CSCOR maintains a regional approach to its research that will continue to advance management capabilities in dealing with all the Nation’s major HAB threats.

z Click here for Information about CSCOR's Regional HAB Research Magnified HAB cells (Alexandrium). Photo credit: WHOI

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# Page 1 of 1 CSCOR: Stressors : Extreme Natural Ev ents : Harmful Algal Blooms: Overview

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