About Algal Blooms

Algal blooms that cause adverse effects are known as Harmful Algal Blooms (HABs). When favorable environmental conditions exist, algae can reproduce rapidly and form blooms that appear as surface scums, water discoloration, or both. Blooms also cause major changes in water chemistry, including high pH and dramatic swings in dissolved oxygen. Lack of oxygen created by decomposing algal blooms sometimes results in fish kills and other aquatic life impacts. 

Some algae, especially blue-green algae, can produce toxins. These toxins have been linked to adverse health effects in wildlife, domestic pets, and humans. DWR currently tests samples for microcystin, one of the most common and well-studied algal toxins. 

When public health concerns arise from algae blooms, local health departments and the N.C. Department of Health and Human Services determine an appropriate response with technical support from DWR. Common actions include swimming closures, contact advisories, and the issuance of public notifications.

In addition to environmental and public health concerns, blooms can lead to economic losses due to increased drinking water treatment costs, decreased tourism and recreation, remediation efforts, fisheries losses, and decreased property values. 

Track an Algal Bloom

Visit our Algal Bloom and Fish Kill Dashboard to find more information on reported algal blooms statewide.  

Report an Algal Bloom

Report an algal bloom on your phone, tablet, or PC 

Find and contact your regional office staff 

Helpful links related to algal blooms: 

• Frequently Asked Questions Regarding Blue-green Algae and Cyanotoxins  
• Identifying Cyanobacterial (Blue-green) Algal Blooms 
• N.C. Department of Health and Human Services: Algae Blooms
   

Staff Contacts

Related Programs

N.C. DEQ Nonpoint Source Management Branch