Cyanobacteria are unicellular or filamentous organisms that, like other bacteria, lack membranes around their internal cellular structures. Their popular (although scientifically inaccurate) name, blue green algae, refers to the green (chlorophyll) and blue (phycocyanin) pigments in their cells, although some species contain the red pigment phycoerythrin. Unlike algae, cyanobacteria can use nitrogen from the atmosphere, permitting them to thrive in nitrogen-limited waters.


Lyngbya majuscula

common name: fireweed, mermaids hair
features: forms red to brown unbranched tangled masses of fine (~ 50 µm) filaments 10-30 cm long, resembling a tangled mass of long straight human hair.
habitat: common in seagrass communities in sheltered estuaries and bays, growing either as benthic mats, as an epiphyte on seagrass leaves or detaching and drifting in the water column within seagrass communities or unvegetated areas.
blooms: Pumicestone Passage, Deception Bay, Eastern Banks and Canaipa Passage.
warning: touching Lyngbya majuscula filaments releases toxins which destroy skin cells, and can cause intense pain around the affected region and skin ulcers which require medical attention. Inhaling the air around dried can cause asthma-like symptoms.

Trichodesmium (Oscillatoria) sp.

common name: sea sawdust
features: reddish brown, unbranched, fine (~ 10 µm) filaments to 0.5 mm long typically aggregated into larger clumps, millimetres in diameter.
habitat: aggregrated clumps float on the water surface, superficially resembling sawdust; single and smaller bundles of filaments can be just visible suspended in the water column.
blooms: aggregated clumps of this tropical species are transported into southern Queensland waters by the southward-flowing East Australian Current to cover large areas of the sea from Noosa south along wave exposed coasts (Point Cartwright, Caloundra). This species enters Moreton Bay via the wide northern opening and South Passage and has been recorded from Scarborough, Brighton, Wynnum, Wellington Point, Eastern Banks and Peel Island.