Dolichospermum (Anabaena)

Identification

• Green colored coiled filaments
• Bead or barrel-shaped cells
• Can form thick “green paint” scum on lagoon surface
• Heterocytes are yellow/green

Why Do I Have It?

• Insufficient aeration
• Overload of organics
• High levels of soluble phosphorus
• Calm and warm water
• High levels of sludge buildup

Treatment

There are many ways to treat Dolichospermum. We recommend adding Argos, a chelated copper algaecide. Argos will damage the cells, causing them to leak and die. AquaSticker can speed the treatment process by disrupting the microbiota of this algae which weakens it, allowing the Argos easier access to the cells. In situations with high levels of soluble reactive phosphorus, binders such as alum or aluminum chlorohydrate may help to precipitate some of this phosphorus out of the water column. Sludge can be physically removed by dredging or a non-disruptive option: SludgeRx. This can aid in sludge reduction and prevent the resuspension of nutrients, such as nitrogen and phosphorus.

Under the Microscope and in Your Plant

The floating planktonic forms of Anabaena are now classified as Dolichospermum, while its benthic forms are still referred to as Anabaena. Dolichospermum, is a filamentous, blue-green cyanobacterium with bead or barrel-shaped cells. Dolichospermum can form a thick “green paint” scum on lagoon surfaces with low water movement. If scum is present it can be an indication of insufficient aeration. The presence of Dolichospermum in a wastewater lagoon is typically a symptom of an inefficient treatment process. This may occur due to the overloading of organics into lagoon systems as it is rare to see this alga in typical aeration basins/typical lagoon systems with normal BOD loading rates.

Dolichospermum can form gelatinous masses which can produce toxins. This alga is typically found in late spring to autumn, free-floating in slow-flowing or still water columns. The typical cause of this alga is high levels of soluble phosphorus. This may be caused in lagoons with low dissolved oxygen. Dolichospermum has special cells within the filaments call heterocytes that can help this alga with nitrogen fixation that converts atmospheric nitrogen to ammonia. This fixed nitrogen is distributed from the heterocyte throughout the filament.

Interesting Facts

• Some species of Anabaena can produce a substance similar to cocaine; this substance can cause damage to the liver, gastrointestinal tract, respiratory arrest, and can even cause cancer