There are also water-plants, what contain poisonous matters and cause the human organism poisoning. Such are the microscopic zilalges (cianobakterijas), pirofitalges and kramalges (diatomejas), which meet both in fresh waters and in seas and in oceans. Especially popular in latter days in the world pirofitalges and kramalges, which in masveida propagates oneself well-disposed circumstances have become in this new, causing the phenomenon, which call for water “flower”. Water from this water-plants paints green, zilzala, brown or in other paint and often only obtain an also unpleasant stink. A few from this water-plants contain toxic matters, what can do poisonous various sea products spent by human: fishes, various edible gliemenes and cancroid. Such are pirofitalges from gintim Dinophysis and Alexandrium, kramalges from family Pseudo-nitzschia. In the world this is a very much aktuala problem.
In fresh waters the toxic zilalges meet from microcistu, afanizomenonu and anabenu family. Them all are microscopic water-plants, which exceptionally rich in the rivers and in lakes propagate oneself in well-disposed growths in the conditions when there are food matters and conformable temperature in a seizing amount. Then this water-plants propagate oneself masveida. Later dying off, this water-plants sink oneself in the bottom of water pools, there decompose and litter water. In the Latvia rivers and in lakes water “flower” is often caused by zilalges from mikrocistu family. They form to 8 mm colonies, which are from many spherical or elipsoidalam cages of a long rounded or indefinite form. Such is zilalge Microcystis aeruginosa. In Latvia waters water “flower” is caused also by afanizomenonu and anabenu family water-plants.