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Experts from various fields, such as radiation, biology and infectious diseases, formed an international group and conducted research, which resulted in the discovery that there exist four types of bacteria capable of surviving in the aggressive Martian environment.
Microbiologists have discovered that some species of bacteria can survive in extremely aggressive conditions, both on Earth and in space. These bacteria can thrive in places with high levels of radiation, sun, extreme temperatures and lack of water. Furthermore, one type of bacteria was found outside the space station, and others were discovered in meteorite material.
These results raise concerns about the safety of astronauts traveling to places such as Mars — if bacteria from Earth falls on them or their equipment, it could lead to illness or even death. In their new research, the scientists asked the question about the possibility of survival of bacteria from Earth in Martian conditions.
To test this possibility, researchers created in their laboratory a Martian environment with a replacement for regolith, low temperatures, no oxygen, and exposure to radiation. Then they successively added four types of bacteria: Serratia marcescens, Pseudomonas aeruginosa, Klebsiella pneumoniae and Burkholderia cepacia. All these bacteria are capable of infecting humans.
In the first step the team examined how each type of bacteria responded to each of the modeled factors. They then subjected all four types of bacteria to all simulated conditions simultaneously. They discovered that certain factors, such as the presence of sodium perchlorate in the soil, significantly limit the growth of one type of bacteria — Burkholderia cepacia. In addition, the decrease in humidity levels in the environment has led to a decrease in the survival of all types of bacteria.
However, researchers also discovered that all four types of bacteria were able to survive to some degree when exposed to all the factors characteristic of Mars. Three of them survived for 21 days, and Pseudomonas aeruginosa even multiplied.
The research group concluded that bacteria accidentally falling on Mars could pose a threat to the health of astronauts, especially if they mutate to better survive in harsh conditions.