Baikal water is more oxygenated than human blood, and its transparency is such that it can be seen 40 meters deep. The lake is home to about 2,600 different species of living things, and two thirds of them are not found anywhere else on the planet. On the Day of Baikal, RIA Novosti talks about the most amazing features of this lake.
Continuous endemics
The largest freshwater body of water on the planet is also the deepest. According to various estimates, its depth is not less than 1600 meters. If Baikal is divided among all Russians, then each will have about 164 thousand cubic meters of purest, practically distilled water. It contains very little dissolved and suspended mineral substances and organic impurities, but a lot of oxygen.
It is due to the high content of O2 in the reservoir that there is such an abundance of living organisms, most of which are unique (endemics). These include absolutely all nematodes, worms, sponges, isopods and stoneflies living in the lake, more than half of fish species (59 percent) and aquatic mammals.
Even the viruses of Lake Baikal are unique. In 2016, researchers at the Limnological Institute of the Siberian Branch of the Russian Academy of Sciences discovered and described several previously unknown species of autochthonous bacteriophage viruses that are not found in other aquatic ecosystems of the world.
Toothy plankton
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Baikal owes its unique water purity to invisible crustaceans - Epischura baicalensis, which make up 80 percent of all crustaceans in the lake. Eating bacteria and unicellular algae, these crustaceans, with the help of several pairs of mouth limbs, create a stream of water and at the same time form something like a filter net to catch food particles in the stream. In a day, one individual cleans about a glass of water in this way.
Another feature of the epischura, discovered not so long ago, is strong silicon teeth capable of biting through the hard shell of diatoms, the favorite food of these animals. A tooth (more precisely, a special crown) is located on one of the teeth of the jaws (mandibles) of these crustaceans. Over time, the crowns grind or break off, but new ones grow in their place.
The purity of Baikal water - the result of the vital activity of microscopic crustaceans, the Baikal epischura.
Baikal omul
The Baikal Epishura serves as food for another endemic - the Baikal omul (Coregonus migratorius), a fish of the salmon family that lives only in the lake and adjacent rivers. The omul length is from 30 to 60 centimeters, weight is from 250 grams to one and a half kilograms.
Scientists have long argued about how and when this fish appeared in Lake Baikal. According to one version, 20 thousand years ago, she swam into the lake from the rivers flowing into the Arctic Ocean. But there was another hypothesis: omul is a descendant of pelagic (that is, living in the water column) whitefish from Siberian water bodies, not associated with ocean waters. The issue was resolved by genetic analysis, which showed that omul is a relative of the modern common whitefish and has nothing to do with ocean fish.
Now there are discussions about the number of omul - and again all the hope for genetic analysis. Scientists of the Limnological Institute of the SB RAS took one hundred water samples in different regions of Lake Baikal and at different depths in March 2018 in order to decipher the DNA traces of lake inhabitants contained in it in the near future. These results will make it possible to judge the diversity of animals and their distribution in the lake.
Scientists are going to calculate the size of the Baikal omul population by genetic analysis of lake water.
Golomyanka and the strange way of breeding
Limnologists hope to learn more about the golomyanka (Comephorus baikalensis and Comephorus dybowski), which, unlike other fish species, cannot be examined with an echo sounder, since it does not have a swim bladder.
She also has no scales, and the body is 35 percent fat. Another feature of this fish is that it does not lay eggs, immediately giving birth to young, and at a time - up to two thousand fry. In other words, eggs develop in the mother's body. To activate their growth, according to scientists, even a sperm of a different species is enough. Fertilization as such does not occur, therefore all the young that appear are actually clones of their mother. This method of reproduction is called gynogenesis and is extremely rare in nature.
Golomyanka lives in the water column, right down to the bottom layers. At night it rises closer to the surface, during the day it goes to depths of up to 500 meters. This fish accounts for up to 75 percent of the total biomass of the lake; it is part of the diet of the only aquatic mammal of Lake Baikal - the seal (Pusa sibirica).
Viviparous fish golomyanka can give birth to up to two thousand fry at a time.
Mysterious Baikal seal
The Baikal seal, like the golomyanka, has an unconventional approach to the issues of reproduction - in unfavorable conditions, it is able to suspend pregnancy. The embryo stops development, but does not die or collapse, but falls into suspended animation, which lasts three to five months. This method of regulating pregnancy is very rare and is known only in 0.05 percent of mammals. The seal masters it by the age of four to seven, when it reaches puberty.
This animal perfectly swims under water, accelerates up to 25 kilometers per hour and dives to a depth of 200 meters. Sometimes in half an hour the seal undergoes a pressure drop from one to 15 atmospheres, but this does not lead to decompression sickness. The animal does not breathe under water, which means that the saturation of tissues and blood with gases remains that which corresponds to atmospheric pressure.
There are different opinions about the appearance of seals in Lake Baikal. Some scientists believe that this animal swam into the lake from the Arctic Ocean several thousand years ago (according to biological characteristics, the Baikal seal is close to the ringed seal that lives in the seas of the Far North and the Far East). Others believe that the entire family of real seals, namely the Baikal seal, was originally formed in large freshwater reservoirs of Eurasia and only then settled in the Caspian Sea and the Arctic Ocean.
Baikal seal - one of three species of freshwater seals in the world.
Alfiya Enikeeva