Fresh water is the most valuable resource in the world. According to the UN, in a decade two out of three people will be affected by water scarcity in the world. And by the middle of the 21st century, 78% of the population will be in the same situation. According to various estimates, the share of fresh water in the total amount of water on Earth is only 2.5 — 3%. About 85 — 90% of fresh water reserves are contained in the form of ice. Russia occupies a leading place in the world in terms of surface water resources. About 20% of the world's freshwater lake reserves and more than 80% of Russia's reserves are concentrated in the unique Lake Baikal.
Epishura is a species of planktonic crustaceans from the subclass of copepods, one of the most famous endemics (a type of plant or animal that occurs in a certain area and nowhere else) of Lake Baikal. This dominant species of Baikal zooplankton plays an important role in the food pyramid of the freshwater "ocean". It feeds on bacteria and unicellular algae, and in a day a small crustacean is able to filter about one glass of water, thereby participating in the purification of Baikal waters.