The nature of our planet is unique. Interestingly, there is nothing stationary on Earth, everything is changing. We are used to the fact that the main changes in the surrounding nature depend on the person. However, amazing metamorphoses are associated with karst lakes. This article will tell you what karst lakes are.
What it is?
Karst is a layer of land that consists of soft rocks, which, due to their properties, are used by people in construction, i.e. limestone, gypsum, surfaces of sulphate origin, etc. Groundwaters, when flowing, erode such layers, and as a result, dips are formed, which are filled with water. Most often it is fresh. However, if the strata are composed of rock salt, then salt water can be saturated with the minerals dissolved in it. This forms a karst lake. It can occur both on the surface and underground, in caves, which also appear due to the formation of voids in the rock layer. Such caves are also called karst.
Features of Origin
Karst Lake is a foundation pit filled with groundwater. It is formed as a result of the failure of a layer of earth, consisting of soft calcareous rocks. The water in such reservoirs is transparent, because there is no sand at the bottom, but only light limestone, mineralized and purified from harmful biological impurities. Therefore, it can be called "living." Such a reservoir does not warm up to the bathing temperature due to the large number of springs delivering groundwater to the surface. There are few animals in such lakes, but fish are found. How she gets there and what she eats is a mystery! Unlike ordinary ones, the karst lake boasts water that is even off the coast free from duckweed and reed vegetation.
Wandering Lakes
Karst lake can be short-lived, because groundwater, eroding limestone layers, can change direction or go deeper. Then they disappear, and only the legends associated with them remain. Wandering lakes are located in different parts of our country. In the Arkhangelsk region there is a reservoir of Semgo, which several times in a row went into the ground. Once in several years, the Rakdal-khol high-mountain natural reservoir appears and then disappears. In Vytegorsky district in the Vologda region, Kushtozero disappeared within three days. Shimozero, located near Onega, surprises residents of neighboring settlements not only with the fact that at the beginning of summer it is filled with water, but also with the fact that by autumn its contents go underground. This lake has a round hollow that resembles a funnel, because the water in it rotates. This place was called by the locals the Black Pit.
Thermokarst and technogenic karst lakes
The appearance of karst lakes is also associated with a change in the temperature regime in various places. With an increase in average annual air temperature, an ice layer begins to thaw in permafrost areas, voids form, the surface of which sinks and fills with melt water. This is how thermokarst lakes are formed. In addition to this type of reservoirs, there are still technogenic karst formations. Most often, they are formed in places of human development of rocks that served him as building material. The adits and quarries are abandoned, but the resulting voids contributed to the emergence of new karst caves and lakes. So, apparently, this time it was not without human intervention.
