Experts are baffled how they got there, but claim a study shows that they can live in space despite lack of oxygen, zero gravity, extreme temperatures, and cosmic radiation.
Plankton in these stages of development could be found on the surface of the oceans
But, several surveys proved that these organisms can even develop in seemingly hostile conditions, it reported.
They were found on the surface of the space station using “high-precision equipment” and were apparently discovered during an operation to clean and polish the ISS.
“This is particularly needed during long space flights,” he said.
The news agency reported that Mr Solovyev was uncertain “how these microscopic particles could have appeared on the surface of the space station”, adding that the organisms were not typical for Baikanour in Kazakhstan, from where the space station lifted off.
“Plankton in these stages of development could be found on the surface of the oceans.
“This is not typical for Baikonur. It means that there are some uplifting air currents which reach the station and settle on its surface,” he was quoted as saying.