Cyanobacteria: What It Is, How It Affects Us, And What's Being Done
Cyanobacteria might sound familiar to some Upper Cape residents, and for good reason: levels of this prokaryotic bacteria have been on the rise in freshwater ecosystems across the region for years and with many Upper Cape ponds being monitored this summer, education regarding cyanobacteria is crucial.
Town health officials are working with the Association to Preserve Cape Cod to monitor blooms of cyanobacteria in addition to raising public awareness of the risks and advocating for increased attention to this public health issue.
What Are Cyanobacteria?
Cyanobacteria are regarded as one of the earliest known life forms on the planet. Related to bacteria but also capable of photosynthesis, these microorganisms are commonly found in the phytoplankton community of freshwater, brackish, and coastal environments. Cyanobacteria occur naturally and play a critical role in our ecosystems, including serving as an essential source of atmospheric oxygen. But under certain conditions, cyanobacteria grow quickly and become toxic in large quantities.
“They’re ancient in their origin but very interesting in terms of their physiology,” said Judith McDowell, retired oceanographer and current president of the Falmouth Water Stewards. “It’s really a diverse group of species and a diverse group of toxins… and they’re really not all bad. It’s the blooms that cause toxins, not the species itself.”
Overabundant cyanobacteria growth — called blooms — release hazardous amounts of cyanotoxins and are being recorded more frequently due to factors such as rising global temperatures and excessive nutrient deposits in local ponds. Blooms thrive in warm, stagnant, eutrophic water and when present, often give the water a scummy blue-green appearance and may even alter its taste and smell.
What Are The Risks?
The CDC considers cyanotoxins to be one of the most powerful known natural poisons and there are currently no remedies to counteract the effects. There are various types of cyanotoxins, but public advisories and closures are usually based on the amount of microcystin, the most prevalent form.
Cyanobacteria blooms can look different depending on the environment. Some blooms float to the top and are easy to spot while others rest below the surface, just out of sight. Sometimes blooms have a foamy or slimy appearance, or they may look like mats of harmless algae. For this reason, health officials and the APCC have prioritized public education on cyanobacteria blooms and are encouraging residents to be vigilant when it comes to utilizing the Upper Cape many water bodies.
“It’s important not only to get the samples, analyze them, and find out which ponds are being impacted but also get the word out to people as to why it’s important not to send your kids into water that is contaminated with these potential toxins,” Dr. McDowell said.
Residents are advised to avoid all contact with water that is contaminated by cyanobacteria blooms, as there is a high risk for adverse health effects. Caution should also be exercised at all ponds that test above the low-risk tier, as even moderate levels of cyanotoxins can lead to health issues. Local health officials and the APCC ask people to avoid these areas as much as possible, even while boating, to mitigate risks.
Accidental consumption of contaminated pond water could lead to skin irritation, headaches, fever, sore throat, dizziness, diarrhea, abdominal pain, vomiting, asthma-like symptoms, muscle aches, liver and kidney failure, and, in certain extreme cases, death.
Cyanotoxins are especially hazardous for children and pets. Pets that have come into contact with contaminated water should be rinsed off immediately and thoroughly to keep them from licking off and ingesting cyanotoxins from their fur.
What’s Being Done About It?
The cyanobacteria monitoring program was developed in conjunction with scientists from the University of New Hampshire and initiated in spring 2017. The program was intended to fill the gaps in state and town monitoring after an increase in harmful cyanobacteria blooms was recorded in freshwater ponds across the Cape.
“Really, what we’re trying to do is get snapshots of each of these ponds so we get a better understanding of how this changes from year to year and which ponds may be the most vulnerable,” said Dr. McDowell.
Dr. McDowell said she has had an interest in natural toxins in marine environments since the 1970s when she was a graduate student at the University of New Hampshire. When she began working with the Falmouth Water Stewards, she was intrigued by the work they were doing, monitoring local ponds, and wanted to expand the program.
“I wrote a couple of small grant proposals just to get enough money to provide sample analysis,” Dr. McDowell said. “We started a couple of years ago with two ponds just to see if we got any results, and then we increased the number of ponds. … Nothing we’re doing is really earth-shattering, but it’s nice that you have 14 ponds being sampled on the same day every two weeks throughout the summer, and if there is a problem is identified the APCC will send someone out and they’ll do another round of more intense sampling at the ponds that have a questionable level of cyanobacteria activity.”
Various factors can be attributed to this uptick in HCBs but rising temperatures and excess nutrients have emerged as two of the bigger causes. While most blooms will dissipate on their own after some time, certain bodies of water have proven to be chronically eutrophic: Santuit Pond in Mashpee, for example, has historically been a problem site when it comes to hazardous blooms due to excess nutrients deposits in the pond.
A surplus of nutrients in freshwater bodies often comes from human-related sources, such as improper disposal of fertilizer or waste products, leaking septic systems, and poorly managed stormwater runoffs.
Health officials and APCC are currently focusing on sampling ponds commonly used for recreational activity. The organizations are already hard-pressed for resources and relying on volunteers and citizen-science groups to help draw samples.
“People say, ‘Why aren’t you monitoring my pond? I swim here every day, this is a high priority!’ but we only have so much money,” Dr. McDowell said. “There are over 150 ponds in Falmouth alone, and we can’t possibly sample all of those. But there are also things that people can be aware of, like if you see unusual cloudiness all of the sudden or a lot of particulate matter… It’s really a very iridescent, blue-green type of slime along the shoreline. And it’s important; even if a particular pond isn’t being monitored, it makes people aware of the signs to look for.”
Bi-weekly sampling is done on Tuesdays by volunteers from the Falmouth Water Stewards in collaboration with the APCC and the Barnstable County Department of Health and Environment. Once the samples have been analyzed, results are posted on the APCC Interactive Map, accessible through their website. Sampling will continue through mid-October.
“The effort right now is to make people aware when there’s a bloom and why that advisory is important to listen to,” Dr. McDowell said. “You can look for the signs yourself, and if you have any concerns or you see that the water quality is changing, just alert someone. We’d be happy to come out and take a sample.”