A strange discovery on the International Space Station has left scientists baffled. It turns out that the space station has traces of living sea plankton on the surface of the spacecraft that orbits more than 200 miles above the Earth’s surface, and well above the planet’s atmosphere.

“The results of the experiment are absolutely unique,” said Russia’s chef Space Station scientist Vladimir Solovyev. “We have found traces of sea plankton and microscopic particles on the illuminator surface. This should be studied further.”

Solovyev said that the plankton is not a form of alien or extraterrestrial life. In fact. the organisms are native to oceans right here on Planet Earth. But how they got on the Space Station is total mystery.

The organisms were discovered during a routine polishing of the Space Station illuminators, the type of housekeeping that is “particularly needed during long space flights,” Solovyev said.

Scientists believe that the organisms could have been living on the outside of the International Space Station for many years. The first components of the space station were launched in 1998 and the station has been occupied by different crews of astronauts for almost 14 full years now.

But not until Russian astronauts Olek Artemyev and Alexander Skvortsov discovered the plankton during recent spacewalk were scientists aware that the living organisms had attached themselves to the Space Station — somehow.

The Russian science chief said he was in the dark as to “how these microscopic particles could have appeared on the surface of the space station.”

While the plankton are of a type that typically live on the surface of large bodies of water, the type found on the Space Station are not native to Baikonur, Khazakstan, which is the area from which the space station was launched.

“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,” Solovyev said.

Certain microscopic organisms can not only survive but thrive even in extremely hostile environments, such as outer space where there is no oxygen and where temperatures are extreme.

But the real mystery remains how the plankton got onto the surface of the International Space Station in the first place.