The secrets of lake Baikal: where in the lake the cleanest water on the planet

© RIA Novosti / Vladimir Smirnoviella in fotovakschool shaman and Cape Burhan on Olkhon islandThe secrets of lake Baikal: where in the lake the cleanest water on the planet© RIA Novosti / Vladimir Smirnoviella in Photobacterium to daily updates RIA Science

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Baikal water is more saturated with oxygen than human blood, and its transparency is such that it is visible up to 40 meters in depth. The lake is home to about 2,600 different species of living beings, two thirds of them found nowhere else on the planet. On the Day of Baikal RIA Novosti tells about the most amazing features of this lake.

Solid endemics

The largest freshwater reservoir of the planet is the most profound. According to various estimates, its depth is not less than 1600 meters. If Baikal is to be divided between all the Russians, then everyone will have about 60 tons of pure, almost distilled water. There are very few dissolved and suspended mineral substances and organic impurities, but a lot of oxygen.

Thanks to the high O2 content in the water is the abundance of living organisms, most of which are unique (endemic). These include absolutely all nematodes, worms, sponges, crustaceans, isopods, and stoneflies that live in the lake, more than half of the species (59%) and aquatic mammals.

Even viruses of lake Baikal unique. In 2016 the researchers of the Limnological Institute of the Siberian branch of the RAS has discovered and described several previously unknown species of autochthonous viruses-bacteriophages, not occurring in other aquatic ecosystems around the world.

Toothy plankton

The unique purity of the Baikal water is obliged invisible crayfish — epishura (Epischura baicalensis), constituting up to 80 percent of all crustaceans in the lake. Eating bacteria and unicellular algae, these crustaceans with several pairs of oral limbs create a current of water and at the same time to form something like a filter net to catch the steam of food particles. During the day, one individual likewise purifies approximately a glass of water.

Another feature of epishura, open not so long ago, strong silicon teeth able to crack the hard shell of diatoms, a favorite food of these animals. The tooth (or rather, a special crown) is located on one of the teeth of jaws (mandibles) of these crustaceans. Over time crowns «worn down» or break off, but in their place the new grow.

Baikal epishura serves as food to another endemic species — the Baikal omul (Coregonus migratorius), fish of the salmon family, found only in the lake and its adjoining rivers. Length omul — 30 to 60 inches, weight — 250 grams up to six kilograms.

Scientists have long debated how and when in the lake there was this fish. According to one version, 20 thousand years ago, she swam in the lake from the rivers flowing into the Arctic ocean. But there was another hypothesis: omul — a descendant of pelagic (i.e. living in the water column) of white fish from water bodies of Siberia that are not associated with oceanic waters. The question allowed genetic analysis, showed that Cisco is a relative of modern common whitefish and no relation to oceanic fish has not.

Now there are discussions about the number of fish — and again, all hope for genetic analysis. The scientists of Limnological Institute of SB RAS in March 2018 took a hundred of water samples in different areas of lake Baikal at different depths in the decoding time contained within it the DNA of the inhabitants of the lake. These results will allow us to judge the variety of animals and their distribution in the lake.

Limnology hope to learn more about the golomyanka (Comephorus baikalensis and Comephorus dybowski), which, unlike other fish species, it is impossible to investigate with the help of sonar, as it has no swim bladder.

It does not have scales, and the body 35 percent from fat. Another peculiarity of this fish — she lays eggs, from birth to cubs, and one — fold to two thousand fingerlings. In other words, the eggs develop in the mother’s body. To activate their growth, according to scientists, enough sperm even fish of other species. Fertilization itself occurs, so all appeared young — in fact clones of their mother. This method of reproduction is called ginogina is found in nature is extremely rare.

The golomyanka lives in the water column, down to the bottom layers. Night it rises closer to the surface, the day is spent at depths down to 500 metres. This fish accounts for up to 75 percent of the total biomass of the lake, she is part of the diet the only aquatic mammal, Baikal seal (Pusa sibirica).

Baikal seal, like the golomyanka, outside the box came to issues of reproduction in unfavourable conditions she is able to pause the pregnancy. The embryo stops development, but does not die and is not destroyed, and falls into hibernation, which lasts three to five months. This method of regulation of pregnancy is very rare and known only 0.05 per cent of mammals. The seal develops to four or seven years when it reaches sexual maturity.

This animal swims well under water, accelerates to 25 miles per hour and dives to a depth of 200 meters. Sometimes for half an hour the seal undergoes a pressure drop from one to 15 atmospheres, but this does not lead to decompression sickness. Under water animal does not breathe, and thus, saturation of tissues and blood gases remains that which corresponds to atmospheric pressure.

About the appearance of the seal in lake Baikal there are different opinions. Some scientists believe that this animal is a few thousand years ago swam into the lake from the Arctic ocean (on the biological characteristics of the Baikal Nerpa is close to the annelid inhabiting the seas of the far North and the Far East). Others believe that the whole family of true seals, namely, these include the Baikal seal, was originally formed in large freshwater bodies of Eurasia and then spread into the Caspian sea and the Arctic ocean.

© CC BY 2.0 / Sergey GabdurakhmanovБайкальская seal — one of three species of freshwater seals in the worldThe secrets of lake Baikal: where in the lake the cleanest water on the planet© CC BY 2.0 / Sergey GabdurakhmanovБайкальская seal is one of three species of freshwater seals in the world