The State We’re In 8/9: Blue-green algae blooms taking the splash out of summer

A bee and butterfly each gather nector on flowers at the Butterfluy Park in East Brunswick, on July 22.

By Michele S. Byers

At New Jersey’s freshwater lakes and reservoirs, summer usually means long days of swimming, kayaking, canoeing, fishing, wading, water-skiing, rafting and paddle-boarding.

But this year, a sickening intruder is spoiling the fun. Blooms of cyanobacteria, commonly known as blue-green algae, have shut down water sports at several of New Jersey’s most popular lakes, including Lake Hopatcong, Greenwood Lake, Spruce Run Reservoir, Swartswood Lake and Rosedale Lake.

Contact with the algae can cause skin rashes, allergy-like reactions, flu-like symptoms, gastroenteritis, respiratory irritation and eye irritation. Both humans and pets are affected. Fish caught in contaminated waters shouldn’t be eaten.

As cyanobacteria levels rise, the bloom can also produce toxins that cause serious health problems like liver and neurological damage.

Cyanobacteria are nothing new. They exist naturally in small concentrations in lakes, ponds and waterways all over the world, according to the New Jersey Department of Environmental Protection.

Human activities are the major culprit in algae blooms.

Cyanobacteria thrive in calm water with increased nutrients, heat and sunlight … and this summer is the perfect storm. The nutrients – mostly phosphorus and nitrogen – come from lawn fertilizers, faulty septic and sewage systems and animal droppings. New Jersey’s unusually high rainfalls washed huge amounts of these nutrients into our waterways.

The Department of Environmental Protection tests for cyanobacteria. If concentrations in lake water exceed the state’s health standard, the agency posts advisories and health departments close public bathing areas.

“It is not arbitrary or excessively strict, as some have suggested,” said Department of Environmental Protection Commissioner Catherine McCabe. “This is the level recommended by the World Health Organization and adopted by New Jersey in 2017. When that guideline is exceeded, the science shows that we can expect three in 10 people who have contact with the water to develop skin rashes or other allergy-like responses, or to experience gastro-intestinal distress.”

At this point in the summer, all anyone can do is wait for the algae blooms to subside. Blooms have begun to decrease at Swartswood Lake and the Indian Harbor section of Lake Hopatcong, and swimming advisories have been lifted in those places.

But there’s plenty that can be done to prevent blooms.

Under a new state law, municipalities and groups of communities have the authority to establish stormwater utilities. These utilities can charge fees to commercial and residential developments that increase stormwater runoff – for example, big box stores with giant parking lots. The fees can be used to pay for “green infrastructure” projects like rain gardens and bioswales to control runoff.

State and local officials can invest in new infrastructure to eliminate “combined sewage outflows.” This is the term for sanitary sewers and storm sewers that join together to send water to treatment plants. In heavy rains, combined systems are often overwhelmed and back up into streets and waterways.

“Sadly, this summer’s lake dramas are just a symptom of bigger issues,” said Cindy Ehrenclou, executive director of Bedminster-based Raritan Headwaters Association.  “It’s time to change the way we manage our own backyards and start focusing on long term solutions that will protect New Jersey’s water quality, not just this season, but into the future.”

You can help:

  • Avoid the use of chemical fertilizers on lawns and gardens;
  • Inspect and maintain home septic systems;
  • Properly store farm animal manure;
  • Plant native trees and shrubs around stream edges and ponds to filter contaminants and keep water cooler;
  • Build rain gardens and use rain barrels to slow down and filter stormwater; and
  • Pick up and properly dispose of pet waste.


New Jersey’s state climatologist expects the state to become warmer and wetter. This isn’t good news, since these conditions will keep fostering algal blooms.  It’s critical that we all take measures now to prevent cyanobacteria blooms from becoming a yearly occurrence in our waterbodies.

Researchers are currently studying whether toxins produced by cyanobacteria contribute to neurodegenerative diseases like Alzheimer’s and amyotrophic lateral sclerosis, also known as Lou Gehrig’s disease. Scientists are also studying whether blue-green algae blooms are connected to brain disease in dolphins.

To learn more about harmful algae blooms, visit the New Jersey Department of Environmental Protection website at

To read studies about the connection between cyanobacteria and brain disease, go to and

For more information about green infrastructure, go to

And to learn more about preserving New Jersey’s land and natural resources, visit the New Jersey Conservation Foundation website at or contact me at [email protected].

Michele S. Byers is the executive director of the New Jersey Conservation Foundation in Morristown.