The search for life on Mars is not easy. It is difficult to get to the red planet and it is very inhospitable to live on.
If not now, there are places on Earth where we can see how life may have been able to survive on Mars. You might think that places like deserts are just deserts, but there is more to Mars than that.
One of the most inhospitable places on Earth is a hot, toxic, acidic lake in a volcanic crater in Costa Rica. The ways in which these microbes adapt to their environment could show us how they lived on Mars.
One of the key findings is that, within this extreme volcanic lake, we detected only a few types of microorganisms, yet a potential multitude of ways for them to survive.
They do this by surviving on the fringes of the lake when eruptions occur. It would be useful to have a wide array of genes.
The hot lake is located in the crater of a volcano in Costa Rica. It is one of the most acidic lakes in the world, with a layer of liquid sulfur floating along the bottom. The water is polluted with toxic metals. It is not teeming with life.
It is not completely uninhabited, either. A research team led by the University of Colorado Boulder found that a single species of microbe was surviving in the lake, from the genera Acidiphilium, which are found living in acidic environments, and have a number of genes.
The volcano exploded in 2017. Since volcanic eruptions had the potential to suck the life out of the lake, a team of researchers decided to revisit the area.
The researchers took samples from the lake, sulfur clumps, and the sediment at the bottom of the lake, and subjected them togenomics andshotgun to identify any organisms that might be there. Not only was Acidiphilium still present, but a small number of other species as well.
The acidiphilium was the dominant species in the lake. The team found genes that might confer resistance to acid and heat, important in an environment that can reach boiling temperatures.
The organisms have many genes that allow them to metabolize substances that might be toxic to others. Sulfur, iron, and arsenic are substances. They have genes for carbon fixation, which allows plants to convert carbon into organic compounds, and seem to be able to process both simple and complex sugars, which can be used in times of energy and carbon privation.
We expected a lot of the genes that we found, but we didn't expect this many. It makes sense that living in an active volcanic crater lake would be how life would adapt.
Astrobiologists are interested in thermal environments. The organisms that thrive in these extreme places harness chemical reactions to produce energy, which they don't rely on sunlight to do. This means that they could offer an analogue for the hidden ocean ice moons of Jupiter and Saturn, as well as other locations far from the Sun.
Scientists believe that life on Earth may have started in a deep hydrothermal environment since it would be safe from the harsh ultraviolet radiation of the young Sun. When Mars was younger, wet, and more volcanically active, there could have been life on the planet.
Wang said that their research provided a framework for how Earth life could have existed on Mars.
Whether life existed on Mars or not is still a big question. We hope that our research steers the conversation to prioritize searching for signs of life in these environments.
The research was published in a journal.
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