Temporary lagoons created by rainfall in the Atacama Desert / Credit: Carlos González-Silva
Water is the source of life on earth, and without water, life can do nothing.
Of course, more water is not a good thing, such as flooding, which means disaster and loss of life;
However, there is a place in Chile where three rains have fallen like never before, but it has broken a big problem, which is a bit confusing.
Atacama interferometer antenna/Image source: ALMA
This place is the Atacama Desert, an area of about 100,000 square kilometers, located in the north of Chile, which for 150 million years has been one of the driest and oldest deserts on Earth.
According to previous scientists' studies of the site's cores, the Atacama Desert has not experienced any meaningful rainfall for at least 500 years.
As a result, Atacama has become an excellent location for astronomical observation, and is now a gathering place for the world's major telescopes, opening a wonderful window for scientists to understand the universe.
However, it finally rained in Atacama, and it was three at once, and many small lagoons formed in the low-lying areas, which disappeared for months.
The three rains were two in 2015 and one in 2017.
After studying the microbial communities after the rain, a team of astrobiologists at Cornell University and the Spanish Astrobiology Center (CAB) were surprised to find that the sudden rainfall in the desert was not a surprise, but a killing:
Due to "osmotic shock", atacama's original microorganisms have drowned, and the cells have been destroyed due to sudden changes in water concentration, resulting in a large number of microorganisms becoming extinct.
In the hardest-hit areas, 85% of the microorganisms extincted!
A rare rainbow in the history of the Atacama Desert / Image source: Carlos González-Silva
The Atacama Desert, though unusually dry, does not mean that it is an absolutely forbidden area for life.
After millions of years of evolution, the bacteria, archaea and eukaryotes there have managed to find their niche in this hellish place on earth and have survived tenaciously.
However, these supposedly exciting heavenly rains have killed them, according to the survey, some lagoon areas have previously had as many as 16 microbes, and only 2-4 species are left after the rain.
The most Mars-like place on Earth / Image source: Valerio Pillar
The fate of the Atacama microbial community has also given scientists a new understanding of the life forms that might exist on Mars.
Previous simulation studies of Life on Mars and testing of Mars probes have been conducted in the Atacama Desert because this place is the most Mars-like place on Earth, cold, dry, and basically lifeless.
The microbes found here have led scientists to believe that Mars, 4.5 billion to 3.5 billion years ago, had vast oceans with abundant water, and it was entirely possible that certain life forms could have evolved there.
Since then, the Martian atmosphere has shrunk, the surface water has disappeared, and if there is life, it will definitely encounter a huge disaster.
But between 3.5 billion and 3 billion years ago, liquid water was still flowing on Mars from time to time, and these beings could have experienced the fate of the microbes of the Atacama Desert, drowning and being completely destroyed in repeated rainfalls.
June 2017 Ataka Ma Empty Rain Clouds / Source: A. Azua-Bustos etc
While the fate of the microbes in the Atacama Desert is sympathetic and heart-wrenching, I'm more worried about why the desert, which has been arid for hundreds of years, suddenly rains.
One possible reason is that global warming has made extreme weather more frequent and transports rain clouds to the Atacama Desert region, so shouldn't we be alarmed?
Stay tuned: