Cyanobacteria: What Are They? Are They Dangerous?
Are They Algae?
Cyanobacteria[1] are not a type of algae, although they create blooms like algae. Often being referred to as blue-green algae leads to the common misconception they are an algal bloom. To the naked eye, no difference is seen between an algal bloom and a cyanobacterial bloom so it cannot be determined whether it is one or the other by sight. A simple jar test can be done at home to determine if bacteria are present. Algae typically bloom best in warm, calm conditions; cyanobacteria have been known to bloom in many types of environments, even going dormant during a freeze, then regenerating immediately after thawing out.
Are They Dangerous?
Most algae and cyanobacteria are not dangerous to people and animals. Some cyanobacteria, given the right conditions, can produce cyanotoxins. Cyanotoxins are dangerous to humans, pets and wildlife. Some bacteria produce a cyanotoxin called microcystin. Microcystin can pose serious health risks, even fatality, to humans or animals if there is long-term or high-level exposure. A few common symptoms of toxin exposure include lung and liver failure, gastrointestinal issues, and skin and eye irritation. Microcystin is not the only toxin produced by cyanobacteria but is the most common. Toxins cannot be identified visually and must be tested for. This Blue Green Algae Test Kit is currently the only at-home toxin test proven to be 99% effective. Testing regularly for cyanotoxins is necessary if people or pets are swimming in or drinking the affected waters.
Can They be Tested for Toxins?
Yes, cyanobacteria can be tested for toxins. This Blue Green Algae Test Kit is a safe, fast, and easy do-it-yourself testing kit. Take a sample of the water, let it react with the chemicals in the provided bottle, and drop one drop onto a test strip. No lab work or waiting needed, you will see results within 15 minutes. If you are concerned immediately about if what you are seeing is cyanobacteria, you can use free and available materials at home to do a jar test. This jar test can help determine whether the bloom is algae or bacteria. If you suspect or determine that you have bacterial growth, the next step should be testing that water for toxins with local agencies/labs or the above test kit.
What Causes Cyanobacteria Blooms?
Bacterial blooms can be caused by many environmental factors. Some of these include excess nutrients, excess aeration, unfiltered sunlight, high temperatures, or stagnant water. As previously mentioned, cyanobacteria are highly unpredictable, so they are difficult to manage or prevent successfully. The bacteria bloom in all kinds of strange conditions at differing rates, therefore making them nearly impossible to prevent or even treat quickly. Using nutrient reducers and/or aeration systems to try and ward off cyanobacteria is not generally recommended unless exact dosage is measured for each water body individually. Nutrient reducers can feed the blooms if ill-dosed, and excess aeration can fast track the growth process, allowing cells to reproduce at a much higher rate. Worst case scenario, these options would cause a bigger problem than the homeowner was originally handling.
Can They be Killed?
There are ways to control cyanobacteria. Research shows that using a copper-based algaecide, such as Copper Sulfate or Mizzen, can provide great results when treating cyanobacteria. If you have determined that you are dealing with toxin-producing cyanobacteria growth, it is best to consult with professionals before treating. Professional lake and pond managers can calibrate treatments to site-specific factors such as exposure-response relationships[2] and rate of cell growth. If done correctly and safely, the bacteria can be effectively treated without a mass release of toxins, which will then allow the water body to be opened back up for use. Effective management plans and successful cyanobacteria treatments will substantially decrease the chances of serious health risks occurring.
Current Best Practices for Cyanobacteria Management
The first and most important step in treating a cyanobacteria bloom is proper identification. As previously stated, it is impossible to determine a difference between algal and bacterial blooms simply by looking at them. To be sure that bacteria is present, a simple DIY test can be performed using a mason jar and a pair of rubber gloves. Collect a surface water sample (avoid getting just “scum” off the top) about ¾ of the jar full. Screw the lid on tight, clean off the outside of the jar, and leave it in the fridge, undisturbed, overnight. In the morning, remove the jar carefully, without shaking or agitating the water at all. If all the green gunk is settled at the bottom, there is likely no cyanobacteria, but rather just regular algae – no harm posed to humans and animals. If it forms a ring at the surface, a bacterial bloom may be present in the water body. The next step, if cyanobacteria is detected, would be to test for toxins using the Blue Green Algae test kit; mentioned and linked earlier. Knowing whether or not toxins are present will help determine the best possible treatment plan for the water body. Early and often treatments will limit the total cell count and toxin production of the bloom, which helps prevent a mass release of toxins into the environment. Managing cyanobacteria can be a little tricky, so it is always wise to consult with local agencies for support if needed.
Can They be Prevented?
Unfortunately, cyanobacteria cannot be prevented from growing completely. They are far too unpredictable and resistant for a prevention plan to be put in place. There is some evidence that using nutrient reducers, such as PhosControl or SparKlear, can help to cut back on the amount of growth seen each season, but they must be used appropriately and site-specifically in order to provide proper results. If used incorrectly according to the site’s conditions, nutrient reducers can feed the cyanobacteria, which only helps it to grow faster. This is another reason why it is imperative to speak with a professional before trying to treat a bloom. If dosed and treated correctly, however, using a nutrient reducer can cut back on the bacterial growth observed in the future.
Conclusion
Cyanobacteria is not something to be messed with, and it can be a complicated process to take care of it. Utilizing reliable resources as well as speaking with local professionals can make treating a bacterial bloom a much smoother and streamlined process. Being knowledgeable about risks involved with cyanobacteria is crucial to a homeowner’s understanding of their water body and can make a difference in how early an issue is detected, which will then allow treatment to begin before the problem becomes overwhelming.
[1] Cyanobacteria: a prokaryotic division of microorganisms that are capable of oxygenic photosynthesis.
[2] Exposure-response relationship: the relationship between the beneficial and adverse effects of a chemical to a defined exposure.
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