Microcystis
Identification
- Single cells that form gelatinous colonies
- Have spherical-shaped cells
- Color of cells vary between green and black
- Appears like dark green pea soup in a lagoon
Why Do I Have It?
- Overload of particulate BOD
- High buildup of organic sludge
- Calm and warm conditions
Associated Lagoon (Pond) Conditions
Microcystis can cause high effluent TSS and generate dangerous toxins within both the lagoon and effluent.
If Microcystis growth is suspected, taking precautions such as wearing a mask and gloves to avoid skin contact is recommended.
Treatment
Algaecides can be effective in controlling Microcystis but are not typically recommended due to the possible release of toxins from the dead cells. Reducing the nutrient build-up and internal release of soluble nitrogen and phosphorus is a recommended way to limit the growth of this cyanobacteria. Sludge can be physically removed by dredging or a non-disruptive option: Sludge Rx. This can aid in organic sludge reduction and prevent the resuspension of nutrients.
Under the Microscope and in Your Plant
Microcystis is a phosphorus-favoring planktonic cyanobacterium that forms gelatinous colonies in wastewater lagoons. In most wastewater lagoon systems, blooms of Microcystis would indicate either a very high buildup of organic sludge or overloading with particulate BOD. Microcystis can form bright green scum but generally only in calm waters. In ponds with vigorous mixing Microcystis is unable to form surface scum and is unlikely to be present in high levels. The cells are spherical and can be green, or black, depending on the presence of gas vesicles. These vesicles help to keep the colonies close to the surface of a pond for optimal light and gas exchange. Microcystis forms colonies of small clusters that are able to rapidly disperse and reproduce, taking over a pond. These clusters then duplicate, resulting in massive amounts of new colonies. The cells are somewhat tolerant of low light and anaerobic conditions and therefore they can begin growing in the sludge. Microcystis can produce cyanotoxins, like microcystin, that are dangerous to humans and animals.