Much of the scientific interest in A. circinalis owes to its production of several potentially harmful cyanotoxins, ranging in potency from irritating to lethal.

[1] Under favorable conditions for growth, A. circinalis forms large algae-like blooms, potentially harming the flora and fauna of an area.

[2] On the A. circinalis filament, the most numerous structures are vegetative cells, responsible for the photosynthesis of high-energy sugars from environmental carbon, water, and sunlight.

Also found along the filaments are gas vacuoles, specialized compartments that inflate or deflate with air to provide upward or downward movement.

With optimal environmental conditions, Anabaena circinalis grow unchecked, forming large blooms that appear as a greenish slime at the surface of the water (fig.

[6] Biological toxicity aside, Anabaena circinalis blooms have the potential to disrupt commercial fishing areas, water-treatment facilities, and recreational waterways.

[7] In some freshwater environments of Australia, A. circinalis are known to produce paralytic shellfish toxins (PSTs),[8] a neurotoxin also found in some marine dinoflagellates.

Saxitoxin poisoning begins with the blockage of sodium and potassium channels, quickly leading to a decrease in neural action potentials, flaccid paralysis, respiratory arrest, and eventually death.

Historically, PCR primers have been employed to isolate and analyze 16S rRNA, a highly conserved region of the cyanobacterial ribosomal subunit.