Efflorescence algale

A efflorescence algale (or bloom in English) is a relatively fast increase in the concentration of one (or of some) species (S) of Phytoplancton in a watery system. This increase in concentration generally results in a coloring of water (red, brown-yellow or green). This phenomenon can relate to fresh water or navy.

One generally considers the threshold of the efflorescence algale to 10 000 cells per millilitre; in certain cases, the concentration can reach several cell million per millilitre.

Impacts

Localized efflorescences can be normal, or more often be exacerbated by the contributions of eutrophisants of anthropic origin. They can then locally even unbalance the Food chain and involve more durable ecological imbalances (Eutrophisation evolving to a dead marine zone, with organic pollution, emissions of Gaz to greenhouse effect, fish mortality and shellfish), on vast zones (largest ateint has 22.000 km2 in 2007, with broad of the estuary of the Mississippi).

Certain types of Micro-organismes implied in these phenomena can secrete Phycotoxine S and, by there, involve intoxications for the Man.

See too

Internal bonds

Phytoplankton
Dinoflagellés
Cyanobactérie
Parent directive Strategy for the seamen circle

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