Bacteria can survive in saline chemicals on planets such as Mars, Titan, Europa and Pluto.

Bacteria can survive saltwater chemicals on planets such as Mars, Titan, Europa and Pluto, according to a new study by a team of transatlantic scientists.
this will bring hope for the future discovery of mysterious extraterrestrial life! In recent years, scientists have discovered surface plumes and subsurface oceans in Europa, organic matter on the surface of Mars, and hydrothermal vents in Titan's oceans, which seem to bring humans one step closer to life beyond the discovery.
such extraterrestrial life must withstand extreme conditions, and previous studies have shown that many types of bacteria can survive extreme conditions.
liquid ocean ice levels on planets far from the sun are very low, because chemicals and salts act as refrigerants, so microbes should live in environments that are temperature-appropriate and have sufficient elements of life.
to study microbial survivability parameters, researchers from the University of Technology Berlin, Tufts University, Imperial College London and The University of Washington conducted tests using Planoccus halocryophilus bacteria, which live in the Arctic permafrost belt.
they placed bacteria in a mixture of sodium, magnesium, calcium oxide and their perchlorate solution, a chemical compound that helps maintain liquid water on the summer surface of Mars.
'Our research has expanded beyond traditional sodium chloride because there are more chemicals on Mars,' said study author Jacob Heinz of the Center for Astronomy and Astrophysics at the University of Science and Technology Berlin.
perchlorates are toxic to life because perchlorates are toxic at high concentrations, and the researchers hope to determine whether perchlorates inhibit bacterial survival, and the amount and concentration of perchlorates inhibit bacteria's viability.
in fact, the survival rate of bacteria in perchlorates is much lower than in all other solutions, although at low temperatures of minus 30 degrees Celsius, the survival rate of bacteria is slightly higher.
Heinz explains that the minimum freezing point reduction - solute will reduce the melting temperature of the solution, perchlorate accounts for 50% of the total mass of the solution, which is much higher than other chloride freezing point reduction concentration.
given its toxicity, the low survival rate of bacteria in perchlorate solutions is not surprising.
Does this mean that Mars no longer supports microbial survival? Heinz points out that life is still possible to survive on Mars.
the presence of perchlorates does not rule out the existence of life on Mars or other planets, bacteria in a 10 percent concentration of perchlorate solution can still grow and survive, and soil perchlorate concentrations on the surface of Mars are less than 1 percent, but Heinz said the concentration of salt in the solution is different from that in the soil.
adapted liquid perchlorate solution can be diluted to increase bacterial viability, but the concentration and temperature balance needs to be maintained.
Teresa Fisher, a doctoral student at Arizona State University's School of Earth and Space Exploration, who focuses on microbial ecology and planetary habitability, said the results do not rule out the possibility that bacteria could survive on Mars, where the surface may in fact breed microbes.
Teresa told Astrobiology that perchlorates are relatively high in parts of Chile's Atacama Desert, the driest environment in the world, and parts of Antarctica.
I'm surprised what would happen if microbes didn't evolve a way to handle toxic substances. Normally, colder temperatures promote the viability of microorganisms, but temperature conditions are not a "universal" factor - the type of microorganism and the composition of chemical solutions will determine the "best point" of microbial viability.
researchers found that bacteria in a solution of sodium chloride (NaCl) died at room temperature for about two weeks.
at 4 degrees Celsius, the survival rate of bacteria will increase, once the temperature reaches minus 15 degrees Celsius, almost all bacteria survive.
the freezing point of sodium chloride solution (minus 21 degrees Celsius) was higher than other salts, and bacteria in magnesium and calcium chloride solutions had very high survival rates of minus 30 degrees Celsius. "It's not surprising because all chemical reactions, including the reaction that kill bacteria, are slow at low temperatures," said
Heinz.
However, the bacterial survival rate is not much increased at lower temperatures of perchlorate solution, while in lower temperatures in calcium chloride solutions, the survival rate of bacteria can be significantly increased.
" results showed that the bacterial survival rates of the other three traditional saline solutions varied.
the bacterial survival rate in the calcium chloride (CaCl2) solution is lower than that of sodium chloride (NaCl) and magnesium chloride (MgCl2) solutions at 4-25 degrees Celsius, but a further decrease in temperature will increase the survival of bacteria in these three solutions.
researchers conducted several freeze/melt-thaw cycleexperiments on these bacteria, ranging in temperature from 25 to 50 degrees Celsius.
Heinz said there would be some significant surface temperature changes, as well as day and night and seasonal variations, depending on the location of the Martian surface.
the average temperature on the surface of Mars is about minus 60 degrees Celsius, and the temperature at the poles drops to minus 125 degrees Celsius.
, bacteria must withstand extreme temperature fluctuations in order to survive.
generally speaking, salty solutions can enhance bacterial survival during freezing/melting. "Bacteria are in a state of shock under pressure, making specific proteins that help them adjust, survive, and cope with harmful environments,"
Teresa said.
adding 10% of sodium chloride reduces microbial mortality from 20% to 7% and increases the number of freeze-thaw cycles, allowing the number of bacteria to be maintained between 70 and 200.
can produce stable proteins when bacteria are in a state of shock in extreme environments, but bacteria can only produce a certain amount of "shock protein".
the survival rate of bacteria in three different solutions (sodium chloride, magnesium chloride and calcium chloride), in general, the lower the temperature, the longer they survive.
Survival and Development Although the study offers the possibility of extraterrestrial microbes surviving, Heinz highlights the difference between the survival and prosperity of bacteria.
bacteria survive under certain conditions doesnot mean that they are actually growing, and he is currently working on another study to determine the extent to which different salt concentrations affect bacterial reproduction under different temperature conditions.
Teresa affirmed: "There is a clear difference between survival and development, but life still surprises us that some bacteria not only survive at low temperatures, but also metabolize and reproduce."
we should put forward the assumptions as fairly as possible to determine what the microbes need to thrive, not just survive.
"Scientists exploring various salt solutions at different concentrations and temperatures will help scientists focus on searching for life forms, or at least not rule out the possibility of life survival, such as the survival of microorganisms in toxic perchlorate solutions."
, other variable factors also influence life-exploration findings, such as the ability of bacteria to withstand radiation or extreme atmospheric pressure.
even some bacteria have some important factors that we haven't found, but as each study progresses, we'll get more important clues.
Source: ScienceScience