Cyanobacteria Becoming a National Problem
- Swains Lake Association
- Feb 15, 2020
- 4 min read
Updated: Feb 29, 2020
Cyanobacteria outbreaks are becoming more and more common in NH and across the nation, as temperatures in general get warmer. Although Swains Lake has been a bit more fortunate over the years than other lakes in our area when it comes to Harmful Algae Blooms, (HABS), our outbreak 2 years ago, confirmed by Bob Craycraft of UNH, was a wakeup call. Additionally, the photo below was taken on the larger section of Swains Lake near Hall Road, in October.
No cyanobacteria blooms were seen here over the summer, but when a resident photographer presented these photos to an SLA board member, he passed them along to Bob Craycraft of UNH, who said it was unmistakably cyanobacteria and notified the state.
No cyanobacteria blooms were seen here over the summer, but when a resident photographer presented these photos to an SLA board member, he passed them along to Bob Craycraft of UNH, who said it was unmistakably cyanobacteria and notified the state.
No cyanobacteria blooms were seen here over the summer, but when a resident photographer presented these photos to an SLA board member, he passed them along to Bob Craycraft of UNH, who said it was unmistakably cyanobacteria, and notified the state.
On November 1, the New Hampshire Department of Environmental Services, (NHDES), put out a press release that cyanobacteria outbreaks had been noticed along the shorelines of “a few NH lakes and ponds.” The release advised the public to be “cautious of water that has a surface scum, changes color, or appears to have green, grass-like streaks or blue-green flecks in it.” The release went on to say, “some Cyanobacteria strains produce toxins that are stored within their cells, and are released upon the cell death.” It warned of acute health problems that can stem from exposure to these toxins, such as skin and mucus membrane irritation, numbness, tingling, vomiting, seizures and even death. Chronic problems associated with exposure can include damage to the liver and central nervous system.

Cyanobacteria, also known as Blue Green Algae, can grow in all types of water. These algae are single-celled organisms, and use sunlight to make their food. Until this fall outbreak on some NH lakes, they were always thought to live in warm, nutrient rich environments that are high in nitrogen and phosphorus. We now know that warm water is not a necessity. They also multiply very quickly. Occasionally, this algae is found along the bottom and is not seen at all. Slow-moving waters, rich in nutrients from fertilizers and septic runoff, are most susceptible to Cyanobacteria growth. Outbreaks, also called blooms, are most often seen in late summer, but staff at the DES is currently reviewing the cases from October, proof that this algae does not need warm water to get started!
According to the Center for Disease Control (CDC) website, not all cyanobacteria outbreaks are harmful, but those that are, can be deadly. They can grow so thick that they block out sunlight other organisms need. The most harmful ones, the CDC states “are among the most powerful natural poisons known.” Swimmers, pets and aquatic animals are in the greatest danger if they ingest cyanobacteria affected water, either by swallowing it or licking fur.
Although some articles note that breathing the odor from this bacteria from close to a lake surface is dangerous, Loon Preservation Committee, (LPC), biologist Caroline Hughes, said in an email that cyanobacteria is a “current topic of research for them.” She went on to say “the LPC is actively collaborating with Jim Haney’s lab at UNH” in the hopes of learning the effect, if any, there is on loons from cyanobacteria. She noted there have been several loon pairs that have successfully raised chicks on lakes with frequent cyanobacteria outbreaks. One of these is Nippo Lake here in Barrington. However, although breeding currently does not appear to be impacted, the long term effects on loons on these lakes is unknown. Long term, “sublethal” effects from this algae that might not easily be detectable is what they are currently studying and hoping to gain information on.
Currently, there are no remedies to counter the effects of cyanobacteria. Therefore, people and pets should stay out of the water if a bloom is suspected, or if their lake receives a warning from the state.
In fact, these blooms are becoming so widespread throughout the country, that the popular publication “Whole Dog Journal” had an article about the importance of keeping pets out of the water if cyanobacteria is suspected. The article’s writer cited the deaths of 4 dogs in Michigan. The dogs all belonged to the same owner, who did not notice anything unusual that day when they swam and drank the lake water. Tests later showed cyanobacteria in the mud on the lake’s bottom.
Do we need to panic? No. We just need to be aware of the risk and use caution. If you see a bluish haze on the water, what looks like bright green grass clippings floating, stay away and keep pets and children out of the water. Visit the websites listed below often. Heed any warning signs if you see them. Follow the state guidelines for fertilizer use, and keep septic systems in good working order to avoid “feeding” this and other algae. By not feeding cyanobacteria’s growth, we help protect people and pets on Swains Lake.
Amanda McQuaid is the Beach Program Coordinator/Watershed Management Bureau with the NHDES. Any sightings of perceived Cyanobacteria can be sent to: <amanda.McQuaid@des.nh.gov> or <beaches@des.nh.gov>.
The “Cyano-Hotline” is (603) 848-8094.
Also contact any board member of the SLA, so that we can put word out and protect our lake residents. Know your area representative’s phone number, (listed with the board members in this newsletter). If you can safely obtain a sample, do so, and keep it in a sealed jar so we can get it to UNH for analysis.
Additional links with information on cyanobacteria are below:
For Cyanobacteria updates here in NH, visit:
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