Colonial Cyanobacteria from Loch Tallant, July 2000.

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Cyanobacteria are differentiated from eucaryotic algae by absence of internal organelles, particularly chloropasts; chlorophyll is evenly distributed in cytoplasm. May be blue-green in colour, but can also be other colours: brown, grey.

globular cells evenly spaced
in colonial mucilage;
frequently in pairs.
No pseudovacuoles

(a) focussed on upper surface of colony

(b) focussed on edge of colony

(c) as (a)

(d) as (b)

? Aphanothece:
elongate cells in colonial mucilage

Coelosphaerium sp.(?):
Cells in a 3-dimensional colony; in pairs or multiples. No individual or group sheaths visible: cells appear to be distributed at the periphery of the colony.

(a) "natural colours", focussed on top surface

(b)"natural colours", focussed on edge of colony

(c) Preserved with Lugol's Iodine: surface

(d) Lugol's: focussed on colony edge

Gomphosphaeria sp.:
cells heart-shaped or round,
at the end of radiating
strands of mucilage

? Microcystis :
Cells crowded in colonial mucilage.

Synechococcus sp.


Oscillatoria sp.


John Kinross