Baikal is a wonderful lake of exceptional purity. To what or to whom does the lake owe its peculiarity? They say that after two or three days it is useless to look for a drowned man in Baikal. It turns out that a small, barely noticeable to the eye, copepods lives in the lake. He is surprisingly efficient, and his genus is numerous. Thanks to him, the water is filtered at a very high speed. Chistyulya does not tolerate excess that is carried out by rivers, thrown from ships, or enters the lake in any other way.
Myth and reality
Unfortunately, it is very difficult for science to know for sure how many species of representatives of the animal and plant world were found in Baikal, so to speak, in its best times. One by one, these species are disappearing due to toxic emissions into the lake. So the crustacean epishura selflessly rushed to the poisonous waste of pulp mills. And this filling brought death to the little creature.
It is believed that this little creature filters out all the water in Baikal. Yes, the crustacean of this species is one of the main orderlies of the lake, but it does not filter out all the dirt. Examining its oral apparatus under a microscope, one can see an intricately woven, like an openwork trapping net of numerous feathery bristles. Algae, bacteria, ciliates get tangled in it.
But the epishura cannot filter out everything that is in the Baikal water. It always contains turbidity, the particles of which the epishura discards.
Description
The little creature is a planktonic crustacean. The size of an adult is approximately 1.5 mm. An amazing creature, with the name epishura crustacean, is one of the most famous endemics in Baikal. It plays a very important role in its ecosystem and inhabits the entire water column, forming up to 90% of the biomass. The little creature consumes most of the algae. For the Baikal omul, epishura crustacean is the main delicacy.
At all seasons in the water plankton of the lake you can meet different ages of this species of aquatic inhabitants. The crayfish continuously reproduces. The fertility of females reaches 200 eggs per year. This is an average. Two generations grow up in one year. The epishura crustacean reproduces with the help of eggs, which are laid and carried by the female in the egg sac. Eggs can be from 7 to 60 pieces. They all have the same maturity.
Reproduction
Females lay eggs in batches. Under such conditions, eachgeneration is represented by crustaceans from several litters. Between clutches in the winter-spring period, a period of approximately 10 days passes, and in summer it is about 20 days.
If the bag is damaged, as it is not strong at all, the eggs fall out. However, with any irritation from the outside, the female breaks the sac, even if the eggs have not reached maturity. After falling out, they continue to develop in the water.
In Baikal one can often find single eggs in which embryos develop. As an adult, the crustacean Epishura Baikal ceases to grow. Until maturity is reached, it goes through two stages of development: larval and copepodite. Each of them has its own periods, the last of which is sexually mature individuals. The transition between each period of development is accompanied by a molt.
Purification
Baikal has become a habitat for many species of flora and fauna. The crustacean epishura is its endemic, the keeper of purity, and therefore can claim a special place among all the living creatures of the lake. It is almost completely immune to pressure drops. Thanks to this feature, the crustacean lives at different depths.
Up to 85% of permanent plankton in the open areas of the Small Sea is epishura crustacean. The group of animals in Baikal, called endemics, makes up a significant part of all the inhabitants of the lake. And there are about 2600 species. Scientists suggest that not all representatives of the water world have been discovered, but only about 70-80% of their total number.
Habitat
Epishura spends most of the time of the year in the upper layer of water. This is 250 meters. At the same time, a significant number of this species is located deeper. Of course, not only the crustacean epishura performs the function of a lake cleaner. More than 800 species of Baikal underwater inhabitants and not only them are working on this problem. However, the contribution of the above-described representative of the animal world is difficult to overestimate.
Characteristic
Throughout all explored depths of Baikal, epishura crustacean is found. What group of animals can still boast such a population in this amazing lake? A small, almost colorless crustacean is a star of the first magnitude in its habitat. Only fat accumulations near his intestines are endowed with a reddish-orange color. Representatives of this genus are characterized by distribution both in Baikal and in Kamchatka in Lake Kronotskoye and in the Far East in Lake Khanka. Six other species of the same genus have found their distribution in North America.
For researchers, this invertebrate aquatic creature is interesting in itself. Epishuru is still being studied. After all, there is still quite a lot of mystery left in his biology. Ekorol crustacean is also not yet fully understood. Of interest are its strong silicon "teeth", as well as speciation.
How does the distribution of crustaceans change in water layers?
June and the period October-February 30-40% of the representatives of the epishura plus 40-50% of the biomass is below the upper layer (250 meters). In spring and autumn, during the period of homothermy, the individual is distributed throughout the entire water column almost evenly.
The small crustacean epishura is the most important link in the food chain of the lake. It is so numerous and dominates in terms of biomass among other Baikal zooplankton in any season that it serves as an excellent food for all pelagic fish. In fact, there is no juvenile fish living in the coastal zone that would not eat it. Predatory representatives of zooplankton, such as large rotifers and cyclops, also feast on this crustacean.
Where else can you find a small endemic?
In the bays of Baikal, it occurs only when the surface of the reservoir is covered with ice, as well as in early spring, after it melts. At the peak of warming (July, August), the animal completely disappears from the composition of plankton. Such a phenomenon is observed in the Chivyrkuisky Bay. In a small amount, the crustacean is preserved in the Barguzinsky Bay. Epishura comes to the Ambassadorial Sor in winter. In summer and autumn it is not there, except that it will be brought there in single copies by a strong current of water.
In early spring it can be found far from Prorva. With depth, the amount of epishura gradually decreases. The sections of large bays, under the significant influence of the open waters of Lake Baikal, are inhabited by crustaceans all year round.
Baikal waters enter the Angara, Irkutsk and Bratsk reservoirs. Epishura can also be found there. In the deep near-dam part of the Bratsk reservoir, he found a habitat suitable for reproduction. Here the crustacean is a self-reproducing population.
Feeding crustaceans
Epishura feeds on algae. He consumes bacteria to a lesser extent. Hiscan be compared with a waterbug grazing on phytoplankton glades. Studying the biotic cycle in the pelagic zone, scientists found that the epishura removes a third of the primary production of algae, which are the main producers of organic matter, for the whole year.
It is this feature of crustaceans in the food chain that has become the reason for the widespread opinion about the key importance of epishura in the purity of Baikal waters. Its feeding method is of the filter type. And the Baikal diatoms are considered to be the favorite food. The distance between the hairs in the oral cavity allows the use of Baikal tiny picocyanobacteria. Most likely due to this fact, the role of the main cleaner is assigned to epishura.
Environmental issue
Epishura is the most numerous inhabitant of Baikal's fauna. As mentioned, it plays an important role in both the ecosystem and the food chain of the lake. According to scientists, it will take about 10 kg of crustacean to grow 1 kg of juvenile omul. Moreover, an adult omul eats predatory zooplankton, for the cultivation of which it will take approximately 10 kg of epishura per 1 kg of macrohectopus.
It is worth noting that this amazing individual tends to accumulate oil products in his small body. But even with all its hard work and passion for cleanliness, even epishura is not able to completely clean the waters of Lake Baikal. He has one property - legibility and even disgust.
It doesn't automatically filter everything it comes across. Epishura, with the help of receptors, tests each particle by eating edible anddiscarding the inedible. Its filtering apparatus is not limited to particle size testing, but also endowed with spectral analysis to filter out the unnecessary. For example, epishura rarely consumes detritus, diatoms, and other algae. She is selective in food and not all forms attract her.
Therefore, speaking about the purification of Baikal waters, one should not diminish the importance of many others, maybe even not so well-known individuals, making their efforts to purify the lake. First of all, these are protozoa (flagellates and ciliates), rotifers, other crustaceans, bacteria that decompose the same detritus.
Understanding which group of animals the epishura crustacean belongs to and how important it is to have its population of similar species in sufficient numbers, one wonders at the owners of production facilities. In just one day, this small translucent creature is able to filter approximately one glass of water, which has a beneficial effect on the purity of the lake.
Why is there such an attitude towards nature? Won't their children live on our land? Don't they feed on it themselves? Why so litter the environment and especially water bodies? After all, how priceless Baikal is! What will happen if this lake disappears from the face of the Earth? We need to come to our senses and stop sawing the branch we're all sitting on.
At all times the greatest sculptor and architect is nature. The forms she creates are unique and inimitable. The scale of her creations constantly reminds us of her beauty, strength and greatness. Baikal is one of the wonders of mother nature. So let'swe will do everything to preserve the uniqueness of this natural object.
