A Lake SVG is a component of the hydrosphere, which is a naturally occurring water body filled with water within the lake bed (lake bed) and has no direct connection to the sea (ocean). Lakes are a subject of study in limnology science. In total, there are about 5 million lakes in the world.
From the point of view of planetology, the Lake SVG is an existing object that is stable in time and space, filled with a substance in the liquid phase, the size of which occupies an intermediate position between the sea and the pond.
Geographically, the Lake SVG is a closed deepening of the land, into which water flows and accumulates. Lakes are not part of the ocean.
Although the chemical composition of the lakes remains relatively constant for a long time, unlike the river, its filler is significantly less frequently renewed and its currents are not the predominant factor determining its regime. Lakes regulate the flow of rivers, holding hollow water in their pits and giving it away in other periods. Chemical reactions occur in the lake waters. Some elements move from water to the bottom sediments, others vice versa. In a number of lakes, mainly those that do not have runoff, the concentration of salts increases due to evaporation. The result is significant changes in mineralization and salt composition of the lakes. Due to the significant thermal inertia of the water mass, large lakes soften the climate and the temperature of the surrounding areas, reducing the annual and seasonal fluctuations of meteorological elements.
The shape, size and relief of the bottom of Lake SVG pits change significantly with the accumulation of bottom sediments. Overgrowth of lakes creates new relief forms, flat or even convex. Lakes and, in particular, reservoirs often create groundwater retention, causing swamping of nearby land areas. As a result of continuous accumulation of organic and mineral particles in the lakes, powerful thicknesses of bottom sediments are formed. These sediments are modified by further development of water bodies and their transformation into swamps or land. Under certain conditions, they are transformed into rocks of organic origin.