Inhabitants of the lake. Flora and fauna of lakes

A lake is the accumulation of water, which is formed on land in a natural deepening. In this case it is a closed reservoir. This natural formation consists of a bed, which is filled to the brim with water. There are different types of lakes. The reservoirs are tectonic and river, ice and coastal, artificial and crater, mountain and failure. Such a classification indicates their origin.

Features of lakes

Unlike rivers, natural accumulations of water do not have currents. However, they do not belong to the World Ocean. Another of their distinguishing features is the different mineralization of water. So, the deepest lake is Baikal. In this case it is absolutely fresh. An amazing natural formation is the Caspian (see photo) lake. In terms of the composition of the salts, its water is similar to the oceanic one. Previously, it was the Caspian Sea. Now this lake. The changes occurred after the loss of communication with the ocean.

The lakes are grouped according to the water balance and position, according to the nutrient content of the substances contained in its water, and also by their composition.

There are many features. There are lakes of different bottom relief, as well as various sizes and shapes. They receive not only rainwater. They are fed by underground rivers.

On the map of Russia there are more than two hundred thousand lakes. Among them, the largest in the world is Caspian. There is in Russia the deepest lake - Baikal, and also the largest in Europe - Onega and Ladoga.

Habitats

Flora and fauna of lakes has its own special character. Basically, natural reservoirs are home to a large number of representatives of freshwater species, as well as a few saltwater.

The organic population of the lake consists of such components:

1. Plankton. It is a collection of small organisms that are passively transferred by water.
2. Benthos. This group includes organisms, the habitat of which is the bottom or bottom of the lake.
3. Necton. The organisms included in this group are actively moving aquatic animals.

The inhabitants of the lake, as a rule, are located in three main zones. The first is littoral. This is an area that completely covers the coastal zone. The second - profundal. It is a deep-sea region of the lake, which includes a bottom and an adjacent water layer. The third zone is the pelagic. It covers the remaining water mass.

Flora

Lakes are characterized by zonal location of thickets of aquatic and coastal plants. In this case, the nature of the flora changes with increasing depth. So, in the shallow-water zone, sedges predominate. They are located not deeper than one meter, at the very edge of the water. Here grows an arrowhead and a citadel, buckwheat, as well as other types of water-marsh plants.

With an increase in depth to two or three meters, a reed zone begins. In this area grows water horsetail, reed, as well as some other types of plants.

Even deeper is the zone of flora with floating leaves. Here there are water lilies (water lilies), floating rdest, as well as egg capsules. At a depth of four to five meters is the area of submerged plants. These include the head of the head and the urot, as well as broad-leaved puddles.

What kind of fish live in the lake?

The fauna of water bodies is very diverse. In the lake you can find almost all types of freshwater fish. In this case, most live there permanently.

What kind of fish live in the lake? In the littoral zone, there are also sticks and pike, perch and goby. There are fish that prefer to stay at a depth. These include burbot and whitefish. They are inhabitants of the lakes of Russia, living in the pelagic region. Some species migrate periodically. For example, in the summer carp find food and shelter in the waters of the littoral zone. In winter they descend into the middle layers of the lake. They are followed by predators.

Division of lake fish into groups

Differentiate the fauna of reservoirs by the way they feed. The inhabitants of the lake, who prefer plankton for food, are the vendace and the snack, smelt and whitefish. Partly to such fish can be attributed roach and yazya, as well as bream, pike perch and perch (some with the passage of time turn into predators). The inhabitants of the lake with bottom feeding are chub and carp, crucian carp, bream and others. Air and coastal food is preferred for gluing and trout, roach and ide. These fish catch insects flying on the water surface or crawling at the very edge of the water.

Fauna and flora of Ladoga and Onega lakes

The natural world of the largest European reservoirs is rich and diverse. They are home to about one hundred and twenty species of aquatic plants. Along the coast stretches thickets of reeds. Blue-green algae are common in the lake waters . At the same time, there are seventy-six species. The abundance of microorganisms (up to three hundred thousand in cubic centimeters) in the lakes makes it possible to self-purify the waters.
The world of freshwater fish is also rich in these waters. Here you can find salmon and Ladoga slingshot, roach and trout, catfish and smelt, rudd and roach, burbot and pike, and many others.

Baikal

In large lakes and in small coves, the flora and fauna are practically the same as those that are characterized by small fresh water bodies. Clams and snails hide in the mud. In the water layers, pikes are hunted and carps frolic. However, in those areas where the depth is significant, the conditions change drastically. So, in some places the bottom of Lake Baikal lies at a distance of one and a half kilometers from the smooth surface of its water surface. In such a deep pond there are biological organisms. Communities of living beings, which in the distant past have formed in this isolated water kingdom, do not receive replenishments from outside. The wandering animal will be able to enter the lake only against the current of the river flowing into it. And this is not enough for anyone.

Inhabitants of Baikal

The deepest lake in the world is the habitat of five hundred species of plants and one thousand two hundred animals. And almost eighty percent of them can be found only in the waters of Lake Baikal. Among them, large-sized flat worms, having a red and orange color, painted in specks and strips. Lakes in the lake and fish, which can live at a kilometer depth, as well as mollusks, which have very thin shells due to lack of calcium salts in the water.
There is a freshwater seal in Baikal. This is a unique mammal, resembling the Arctic ringed seal.

On Lake Baikal, this freshwater population numbers several tens of thousands of individuals. In the second half of winter, the animal is congested. Thus it brings one or two cubs. The Baikal seal is a remarkable diver, able to dive to a depth of two hundred meters and stay there for up to twenty minutes.

Small animals

Baikal is the habitat of the simplest unicellular organisms. Their food is bacteria, microalgae. Multicellular invertebrate animals on Lake Baikal are divided into many species. The most famous of them is the Baikal epishura. These small crustaceans are the inhabitants of the water column of the lake. In this case, the epishura effectively cleans Baikal waters with its filtering device, consisting of hairs and bristles located on the mouthpiece.

The stony ground of the lake is the habitat for sponges. These are the most exotic animals that inhabit the zero. Fixed colonies of small invertebrates are colored with microalgae in various shades of green. Sometimes the shape of these colonies resembles sea corals.

At the bottom of the Baikal gulfs and in the shallow coastal waters, there are larvae of fifty different species of caddis flies. Growing up, individuals leave the aquatic environment.

Fauna

What kind of fish are found in Lake Baikal? In total, fifty-two species were found in its waters. This number includes the Baikal omul. He is the representative of the family of whitefish. Baikal omul belongs to commercial fish and is the object of sport fishing. Occurs in the zones of underwater slopes, located at a depth of three hundred and fifty meters.

Another fish in Lake Baikal is typical only for this water area? Among the unique inhabitants there are two species belonging to the endemic family of Golomyanka (small and large golomyanka). They are small fish (a little over twenty centimeters long), which live at different depths of the lake and feed on epishura, as well as crustaceans. Golomyanka - food for the seal and omul.

The largest Baikal fish is sturgeon. Is not inferior in size and taimen. Sturgeon, which lives in the deepest lake, is listed in the Red Book of Russia. The duration of his life is fifty years. At the same time he is gaining weight to one hundred and thirty kilograms. Inhabitants of Lake Baikal - small fishes and bottom invertebrates - are the main food for sturgeon.