A lack of balance in nutrients in the water can cause algae blooms, turning waterways green or blue-green. Courtesy NC DEQ.

In the fall, Jill Howell spent four days kayaking down the Tar-Pamlico River and its tributaries. She spent most of the trip paddling through blue-green sludge and dead fish, telltale signs of harmful algae blooms impacting the health of the waterways.

“Large-scale algal blooms shouldn’t be happening,” explains Howell, Tar-Pamlico riverkeeper with Sound Rivers, a nonprofit focused on protecting the health of the Neuse and Tam-Pamlico river basins. “(Algal blooms) are a big sign that waters are in distress.”

While comprehensive long-term data about the presence of algae blooms in North Carolina waterways is lacking, the telltale blue-green sludge has been reported in lakes, rivers, streams, ponds and ocean shorelines across the state, including the Pamlico, Pasquotank and Perquimans rivers in Eastern North Carolina, Lake Wylie near Charlotte and Beaver Lake in Asheville.

Algae is a natural part of an aquatic ecosystem but an imbalance of nutrients, especially nitrogen and phosphorous, in the water can cause the microorganisms to grow out of control, forming algae blooms.

Not all algae blooms are harmful, but some contain cyanobacteria, toxic bacteria that pose serious risks to aquatic life, the environment and human health.

Tracking blooms

“When the algae consume the nutrients (in the water), they also consume the oxygen,” Howell explains. “Oftentimes, when algal blooms are happening, waters are depleted of oxygen, and that results in fish kills because there’s not enough oxygen for the fish.”

While some algae blooms form on their own, excess nutrients from fertilizer runoff, animal manure from industrial farming operations, wastewater and stormwater runoff also contribute to the formation of the blue-green sludge. 

Climate change appears to be exacerbating the issue: Rising ambient temperatures, sea-level rise, higher rainfall and warmer water temperatures also increase the presence of harmful algae blooms in waterways, according to the U.S. Environmental Protection Agency.

National data shows a clear pattern: a significant spike in reports of algae blooms over the past three decades with bloom intensity increasing in more than two-thirds of freshwater lakes.

The N.C. Department of Environmental Quality introduced an Algal Bloom and Fish Kill Dashboard to encourage citizen reports of algae blooms. In 2019, just one report of algae blooms was submitted. Over the last 12 months, DEQ has received notice of 82 algae blooms in waterways across the state.

The increase may reflect better awareness of the tool rather than a rise in blooms, according to Daniel Wiltsie, algae bloom response coordinator for N.C. Division of Water Resources within DEQ.  

Addressing the causes

The Clean Water Act, federal legislation introduced in 1972 to establish wastewater standards, implement pollution controls and regulate the discharge of pollutants into waterways, helped eliminate “point-source pollution,” which occurs when toxins were diverted from manufacturing companies, farms and other operations straight into the water.

“In the late 1980s and early 1990s, algae blooms were really bad,” Howell said. “There were significant policy changes to address it because the scale of the problem was so bad, (but) 30 years later, we’re still seeing extensive algal blooms and extensive fish kills.”

While the legislation made it illegal to use pipes or ditches to divert waste from all sources, including industrial and agricultural operations, into the water, it didn’t eliminate pollution altogether. Instead, Howell notes, “pollution changed.” 

“What’s entering our waterways now looks different than it was 30 years ago, but there are definitely not fewer pollution sources entering our waterways now,” she said.

Howell pointed to “nonpoint-source pollution” like fertilizer, wastewater and stormwater runoff for triggering algae blooms, adding that it’s trickier to pinpoint the source of the pollution when it’s not coming into the water from a specific entry point.

The DEQ reviews all reports of algae blooms. Based on the information provided, staff might conduct a site visit and take water samples and, if cyanobacteria are detected, an advisory will be issued, Wiltsie explained. 

Treatments are not applied to eliminating existing algae blooms. Rather, the blooms are left to disappear on their own. Most last anywhere from a few days to a few weeks, but Howell noted that their presence, even if short-lived, wreaks havoc on aquatic life and can be harmful to human health. The frequent appearances and disappearances don’t make their presence less alarming. 

“Just because it’s a regular occurrence doesn’t mean that it should be happening,” Howell said.

Sound Rivers has focused on promoting green stormwater infrastructure, advocating for sanitary sewer overflow monitoring and notification, and filing a lawsuit to protest the elimination of Clean Water Act protections in an effort to address some of the pollution sources that contribute to algae blooms.

“These things might seem like (they are) a long way from algae blooms and fish kills, but you have to address the problem at the source,” Howell said.

N.C. State University received a $25 million grant to launch the Science and Technologies for Phosphorous Sustainability, or STEPS, Center. N.C. State and eight partner institutions will research solutions aimed at reducing the amount of phosphorous that leaches into soil and water, resulting in algal blooms and coastal dead zones. Among their goals: facilitate a 25% reduction in phosphorous runoff into waterways over the next 25 years to reduce environmental damage.

“Phosphorus-driven algal blooms impair safe drinking water and marine life, and the increasing flux of phosphorus to oceans also leads to an expansion of coastal dead zones,” Ross Sozzani, co-deputy director of the STEPS Center, said in a press release.

“Without intervention, the environmental, economic and sustainability issues involving phosphorus will escalate.”

In addition to legislation, private-sector and institutional efforts, Howell thinks individual efforts, such as advocacy in local government and participation in river cleanups, are required to protect North Carolina waterways. 

“As storms continue to increase and more pollution sources are added, it’s hard to know when the burden will become too much for the system to absorb and becomes irreversible,” she said.

“Something needs to be done to improve the health of the waters.”

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Jodi Helmer is a Carolina Public Press contributing writer based in Stanly County. Send an email to info@carolinapublicpress.org to contact her or any members of the CPP news team.