Transformation of river old-town communities (section of the former river bed). As the old woman separates from the river bed, the flow in it weakens, the water quickly and well warms up, the oxygen concentration in the water decreases. The composition of the inhabitants of the old woman is increasingly different from the river community, the mass of phyto- and zooplankton is increasing. Due to the lack of oxygen in the bottom layer, the reducers do not have time to decompose dead plankton – at the bottom, the sludge layer increases and the depth of the old woman decreases. When the depth reaches 5-6 m, abundant underwater vegetation develops in the old man. This condition is called the “underwater meadows” stage. This leads to a shallowing of the reservoir, with a decrease in depth to 3-5 m, a stage of plants begins, filling the thickness of the water to its surface. The branched shoots of rdest and uruti significantly reduce the illumination of the water column, so plankton dying begins. The next stage is the stage of floating plants (water lilies, egg capsule). Gradually poorer animals, fish disappear. Finally, the old woman becomes so shallow that in the place of the reservoir there is a swamp with thickets of reed, cattail and reeds, then sedge thickets. Soil is formed from dying plants, its surface gradually becomes higher than the level of groundwater, and the soil itself becomes less moist. A sedge swamp is replaced by a flood meadow, a meadow by a willow, a willow by an alder.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.