We get asked about blue-green algae all the time, so here’s the plain-English version of what it is, how to recognize it, and how we actually manage it.
What blue-green algae actually is
Blue-green algae are not actually algae at all; rather, they are types of bacteria called cyanobacteria, which are present in many lakes. This type of bacteria thrives in warm, nutrient-rich waters. When conditions are right, the bacteria can grow quickly, forming blooms.
You cannot eliminate blue-green algae from a lake, as they are part of the overall algal community. We cannot control the water temperature, but we can help reduce the amount of nutrients going into the lake in a proactive manner, which includes the introduction of beneficial bacteria that help consume the excess nutrients.
How to recognize it
Sometimes it can be visible on the water’s surface, and sometimes it is not visible within the water column. Not all blue-green algae are toxic. It can appear very quickly, and is most common during summer and early fall, as this algae prefers warm weather.
This algae can look similar to green paint floating on the surface of the water. It may bubble up in some areas and have a distinctively bad smell.
Why it matters
You may notice dead fish or waterfowl around the lake. This can occur in any pond or lake, but waters that are shallower, that have a higher nutrient load, and receive less oxygen flow have a naturally higher likelihood of an algae bloom of any kind.
Usually, problems arise when there is a large amount of blue-green algae composed of a species capable of producing toxins. One thing that should be recognized is that if the blue-green algae are killed by an herbicide or algaecide, then the dying algae will release their toxins into the water. That is a big reason we don’t simply reach for a chemical knock-down on a blue-green bloom — it can make the immediate problem worse.
Our approach
Our approach is to use beneficial bacteria to consume the nutrients that the blue-green algae feeds on. In conjunction with this, we use a dye to help block the sunlight, thereby helping to starve the bacteria.
The long-term strategy is to devise a plan to reduce the available nutrients in a pond that these algae thrive on. This can best be done via the introduction of supplemental oxygen and beneficial bacteria — which is where subsurface aeration and an ongoing treatment program do the real work.
A word on safety
Because you can’t tell a toxic bloom from a harmless one just by looking, it’s smart to keep pets, livestock, and people out of the water when there’s a visible bloom or scum, and to rinse off with clean water after any contact. If a person or animal is exposed and you’re concerned, contact a doctor or veterinarian.
The bottom line
You can’t get rid of blue-green algae for good — it’s part of the lake. But you can make blooms far less likely by starving them of the nutrients and stagnation they depend on. If your pond blooms every summer, email us the address and we’ll measure it by satellite and reply with a plan and a quote, usually within 1–2 business days.