MOSCOW, May 30. /TASS/. Russian scientists will suggest raising the hypthetical upper border of biosphere to 400 kilometers following the discovery of various microorganisms, including Barents Sea plankton and bacteria from Madagascar, in swabs taken from the surface of the International Space Station (ISS).

As part of the "Test" experiment, Russian cosmonauts took a total of 19 swabs from the outer cover of the ISS between 2010 and 2016.

"Experiments of various years have revealed fragments of Mycobacteria DNA - a marker of heterotrophic bacterial sea plankton in the Barents Sea; the DNA of extremophile bacteria of the genius Delftria; the DNA of bacteria closely related to those found in soil samples from the island of Madagascar; vegetative genomes; the DNA of certain species of Archaea and the DNA of fungus species Erythrobasidium and Cystobasidium," the Russian space agency Roscosmos said in a statement obtained by TASS.

The appearance of sea and ground microorganisms on the surface of the ISS can be explained by the so-called ionosphere lift phenomenon, when substances from the Earth’s surface rise to the upper atmospheric layer (from about 60 km to 1,000 km)

In line with the discovery, Roscosmos scientists, jointly with other scientific groups, have prepared and substantiated a proposal to raise the upper border of the biosphere to 400 kilometers from the current altitude of 20 kilometers.

Currently, scientists analyzing carbon isotope proportions in the samples taken from the ISS in search for samples of extraterrestrial life that could be brought to the station’s surface with comet dust.