Microcystis aeruginosa
Encyclopedia
Microcystis aeruginosa is a species of freshwater cyanobacteria which can form harmful algal blooms (HABs) that are of economic and ecological importance. They are the most common toxic cyanobacterial bloom in eutrophic freshwater.
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
is a light blue-green, appearing dark or brown due to optical effects of gas-filled vesicles
; this can be useful as a distinguishing characteristic when using light microscopy
. These vesicles provide the buoyancy necessary for M. aeruginosa to stay at a level within the water column at which they can obtain optimum light and carbon dioxide levels for rapid growth.
s).
toxins under the right environmental conditions, it has come to be a source of drinking water pollution (which can be rendered hepatotoxic). This can lead to increased economic costs such as water quality mitigation measures in the form of increased costs at water filtration facilities, as well as damage to local tourism caused by lake or other waterway closures due to toxicity concerns.
and other marine life death also.
Characteristics
As the etymological derivation implies, Microcystis is characterized by small cells (of only a few microns' diameter), which lack individual sheaths.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...
. These vesicles provide the buoyancy necessary for M. aeruginosa to stay at a level within the water column at which they can obtain optimum light and carbon dioxide levels for rapid growth.
Ecology
M. aeruginosa is favored by warm temperatures (Oberholster), but toxicity and maximal growth rates are not totally coupled, as the cyanobacterium has highest laboratory growth rates at 32°C, while toxicity is highest at 20°C, lowering in toxicity as a function of increasing temperatures in excess of 28°C. Growth has been found to be limited below 15°C.Toxins
M. aeruginosa can produce both neurotoxins (lipopolysaccharides-LPSs) as well as hepatotoxins (microcystinMicrocystin
Microcystins are cyclic nonribosomal peptides produced by cyanobacteria . They are cyanotoxins and can be very toxic for plants and animals including humans. Their hepatotoxicity may cause serious damage to the liver. Microcystins can strongly inhibit protein phosphatases type 1 and 2A , and are...
s).
Economic importance
Because Microcystis aeruginosa can form persistent microcystinMicrocystin
Microcystins are cyclic nonribosomal peptides produced by cyanobacteria . They are cyanotoxins and can be very toxic for plants and animals including humans. Their hepatotoxicity may cause serious damage to the liver. Microcystins can strongly inhibit protein phosphatases type 1 and 2A , and are...
toxins under the right environmental conditions, it has come to be a source of drinking water pollution (which can be rendered hepatotoxic). This can lead to increased economic costs such as water quality mitigation measures in the form of increased costs at water filtration facilities, as well as damage to local tourism caused by lake or other waterway closures due to toxicity concerns.
Ecological importance
In addition, its effect on dissolved oxygen (DO) content in water can lead to fish killFish kill
The term fish kill, known also as fish die-off and as fish mortality, is a localized die-off of fish populations which may also be associated with more generalised mortality of aquatic life...
and other marine life death also.