In the summer the surface of the rivers often turns green and drags on a film from seaweed which deprive fish of oxygen. It is almost impossible to get rid of water blossoming as process of a pozeleneniye of water is completely natural. But why it happens also what provokes its emergence?
Pozeleneny waters it is most often observed in the middle or the end of summer on a surface of natural reservoirs – the rivers, lakes, ponds. Microscopic seaweed which massively begin to breed in favorable conditions are the reason of this unusual phenomenon. Them are bright sunlight, the increased water temperature, weak inflow of fresh, not stagnant water and existence in the river of organic matter.
Having considered the become green water under a microscope, it is possible to see water which literally teems with green microorganisms.
Among intensively breeding seaweed such monocelled being as an euglena green prevails. In it the chlorolayers painting an euglena in a bright saturated shade of greens contain. In night-time and other conditions of a lack of lighting the euglena begins to acquire numerous organic compounds with which standing reservoirs with the minimum inflows of pure fresh water are so rich. Besides, bright sunlight strengthens growth of the nitchaty seaweed covering with the green threads leaves of water plants, soil and the surface of the rivers.
Why the rivers begin to turn green?
Pozeleneny waters in Volga is explained by reproduction of blue-green seaweed which were localized on certain sections of the river earlier. After economic development of a river basin and control of a drain of Volga, the intensive growth of seaweed caused by increase of biogenous loading began to be noted. The similar effect provoked also dumping of large volumes of industrial precipitation and waste into superficial parts of the Caspian Sea.
Considerably aggravated a situation and creation of reservoirs in which still water the blossoming of seaweed reached the maximum.
Increase in growth of seaweed also began to happen to addition of industrial "fertilizers" which served as great food for these hardy plants. There are hundreds of species of blue-green seaweed, however the strongest pollution of water is caused by only nine of them. The ideal habitat of seaweed is shallow water with a big area, weak channels and not shaded environment. The soil near such rivers is often enriched with phosphorus and nitrogen which accelerate growth of seaweed so that sometimes all surface of a reservoir becomes covered by a mucous blue-green film. After dying off of an alga poison water with products of the decomposition and also phenols, an indole, skatole and other toxic agents.