Microcystis is the genus of freshwater cyanobacteria which includes the harmful algal bloom Microcystis aeruginosa

Microcystis aeruginosa

Microcystis aeruginosa is a species of freshwater cyanobacteria which can form harmful algal blooms that are of economic and ecological importance...

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Etymology

The generic moniker Microcystis derives from the Greek mikros ("small") + kystis ("bladder")

Characteristics

As the etymological derivation implies, Microcystis is characterized by small cells (of only a few microns' diameter), which lack individual sheaths.

The cells usually are organized into colonies (large colonies of which may be viewed with the naked eye) that begin in a spherical shape, but losing their coherence to become perforated or irregularly shaped over time.

The coloration of the protoplast

Protoplast

Protoplast, from the ancient Greek πρῶτον + verb πλάθω or πλάττω , initially referred to the first organized body of a species.Protoplast has several biological definitions:...

 is a light blue-green, appearing dark or brown due to optical effects of gas-filled vesicles

Vesicle (biology)

A vesicle is a bubble of liquid within another liquid, a supramolecular assembly made up of many different molecules. More technically, a vesicle is a small membrane-enclosed sack that can store or transport substances. Vesicles can form naturally because of the properties of lipid membranes , or...

; this can be useful as a distinguishing characteristic when using light microscopy

Microscopy

Microscopy is the technical field of using microscopes to view samples and objects that cannot be seen with the unaided eye...

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Species

Dozens, including:

• Microcystis aeruginosa
  Microcystis aeruginosa
  Microcystis aeruginosa is a species of freshwater cyanobacteria which can form harmful algal blooms that are of economic and ecological importance...
  
  
• Microcystis argentea
• Microcystis elongata
• Microcystis holsatica
• Microcystis lutescens
• Microcystis marina
• Microcystis pallida
• Microcystis salina
• Microcystis thermalis
• Microcystis viridis