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Learn About Algal Blooms in Northeast North Carolina

Above: algal bloom, Arrowhead Beach canals. Courtesy N.C. Division of Water Resources

Katie Mosher,, 919-515-9069

Algal blooms in northeast North Carolina waters are in the news and generating questions from residents and local officials. The blooms, often containing high levels of toxins, also have been the focus of academic and community research partners, state and federal agencies, and North Carolina Sea Grant.

While research projects are in progress — to identify environmental factors that foster the blooms and also to see how toxins may move through the ecosystem and food web — Sea Grant has updated its Algal Blooms: Things to Know fact sheet that includes a dozen links for online resources, including how to report new blooms.

“We also provide basic information about the biology of the blooms and their impacts,” notes Gloria Putnam, Sea Grant’s coastal communities specialist. For example, the text explains:

Algae are photosynthetic organisms naturally found in aquatic environments. Under the right conditions, they multiply to high concentrations called blooms. Some blooms are blue-green algae capable of producing toxins that can cause skin irritation, illness or in rare instances death in pets, livestock and people. These blooms are known as harmful algal blooms or HABs.

The current blooms are not the first in the coastal region, the researchers and resource managers noted in recent forum in Edenton that drew more than 80 people. Historic reports date at least to the 1700s. Significant blooms in the 1980s brought about regulations that limited discharges — known as point source pollution — into waterways in northeastern counties, including the Chowan River watershed.

But the blooms have returned. Since 2015, HABs appear to be on the rise in the Chowan River and Albemarle Sound, and nearby waters. Nutrients continue to flow into the waters from nonpoint sources. Increased water temperatures may also play a part.

In the summer of 2019, some N.C. blooms contained up to 620 ug/L of microcystin toxin. The World Health Organization considers 20 ug/L a moderate health risk for swimming. Thus, state agencies issued warnings to avoid contact with the waters.

Putnam praises the collaborations and community interest that were highlighted at the Edenton meeting. “It’s encouraging that so many people are seeking answers and raising awareness,” she said.

Online Resources:

The algal blooms fact sheet is available here:

Other links include:

  • Report Blooms and Fish Kills. Let the N.C. Division of Water Resources know when you see a bloom by using the reporting system at:
  • Join citizen science efforts. Check the Chowan Edenton Environmental Group’s Facebook Page:
  • Get background from the N.C. Department of Environmental Quality’s Division of Water Resources:
  • Understand health risks with information from the N.C. Department of Health and Human Services:



Follow the Coastwatch Currents blog for new updates on collaborative research on algal blooms in northeast North Carolina.