According tomedia reports, the origin of life on Earth has been a mystery to scientists for decades, and now, new research suggests that early life on Earth may have started in “poison hot springs”, while an in-depth understanding of the formation of complex molecules on Earth will help guide us in the search for life forms on other planets in the solar system.
Picture from WiKiMedia
In The Bumpass Hell in California’s Larsen Volcanoes National Park, the ground is boiling, the air smells of rotten eggs, bubbles gushing from mud pits, the sound of viscous liquid bursts, and burning steam spewing out of the Earth’s crater. The terrible terrain was named after the cowboy Kendall Bumpass, who had to have his leg amputated in 1865 when Bumpas approached and stepped on a thin crust.
Pictured is the “Bumpass Hell” in Larsen Volcanoes National Park, California, where moist and dry cycles at the edge of geothermal pools are thought to facilitate the gathering of biomolelees.
Some scientists argue that life on Earth evolved in seemingly uninhabitable conditions, and that hot springs such as The Bonpas Hell could promote chemical reactions that connect simple molecules, taking the first step toward complex life before they roam the planet. Other scientists, however, have focused the starting point of life on the thermal nozzles deep in the ocean floor, where mineral-rich hot water rolls out of cracks in the ocean floor.
The latest study provides important theoretical support as researchers study and debate where life on Earth was first born and how it explodes. Natalie Batalha, an astrophysicist at the University of California, Santa Cruz, says understanding the origins of life on the planet could provide important clues as to where to look for extraterrestorial life.
Wenonah Vercoutere, a chemist at NASA’s Ames Research Center, agrees, saying: “This latest study is important for the future of space exploration, with the same physical rules for the entire universe, so why can’t biological laws continue?” Why is there no biological activity in the universe as a whole? “
Land Hot Springs
From the biochemical core, the composition of life depends on only a few elements: chemical elements, water, or other media that can react chemically, and the energy sources that power these reactions. On Earth, all these ingredients exist in land hot springs, home to some tenacious creatures. For example, a 2016 article in the journal Nature Communications noted that in Great Boiling Springs, Nevada, the hot spring temperature was as high as 77 degrees Celsius, but microbes managed to survive in the waters near the hot spring clay beach.
Jennifer Pett-Ridge, a microbiologist at Lawrence Livmore National Laboratory in California, said: “Living conditions like this can be very close to earth’s early environment, so these forms of life are most likely to be associated with some of Earth’s early life. “
Microbes in hot springs can form biomes called microbial mats, which are made up of multiple layers of microbes that are found in geothermal regions around the world, including Yellowstone National Park in the United States, Galga Hot Springs in southern Russia, and the site of the “Bangpas Hell” in California’s Larsen Volcanoes National Park.
Over time, microbial pads can form laminational rocks, microbes, and minerals that accumulate overlaid structures that map geological changes over time, just like the annual wheels of trees.
Researchers have found evidence of laminated rocks in 3.5 billion-year-old rocks in inland Western Australia, as well as evidence of hot spring deposits, published in the 2017 issue of the journal Nature Communications. The latest findings, along with previous microbial-related signs, led the team to believe that some of the earliest life on Earth was proliferating in such a hot spring environment.
David Deamer, a biophysicist at the University of California, Santa Cruz, spent 45 years exploring how life on Earth evolved by studying lipids, the oily molecules that make up the membranes around cells.
Demmer is a strong supporter of the theory of the origin of hot springs- life, and he has confirmed that earth hot springs can produce bubble-like follicles, the outer layer of which is made up of lipids. Structures like this may be ancestral prescells of modern cells.
Scientists believe that The Bravo Hot Springs in Iceland was one of the environments where life might have been formed on early Earth.
Bruce Damer, an astrobiologist at the University of California, Santa Cruz, who uses computer science to solve the problem of the origin of life, worked with Demmer to test whether conditions in hot springs could prompt a cohesive reaction in which two molecules combine into a larger synthesis.
When water spills out of the hot spring and evaporates, the molecules in the liquid condense and connect, and subsequent splashes increase the number of molecules that can react with additional condensation when the liquid evaporates again, and repeated wetting and evaporation can create molecular chains.
In 2018, Demmer conducted an experiment in an active geothermal region of New Zealand, known as the “Gate of Hell”, to test this hypothesis by preparing a vial containing the ingredients needed to assemble the RNA chain, a nucleic acid that acts as a messenger in protein synthesis and may have catalyze chemical reactions related to the origin of early Earth life, a mixture of two of the four RNA-building components that are linked together to form the RNA chain.
Demmer places the open vial in a metal box, which is the size of two CD boxes, and then places the unit in a near-boiling pool of heat. To simulate the humid and dry environment of the original Earth, he injected acidic hot spring water into the vial, which gradually evaporated and dried, and then repeated several wet-dry cycles. When he took the vial back to the lab, he found that it contained 100-200 nucleotide-length RNA strands.
The study, published in the December 2019 issue of the Astrobiology Journal, suggests that complex molecules can form in hot springs, supporting the hypothesis that life on Earth may survive and develop in such an environment. In 2020, Damer and Demmer and colleagues returned to the Hell’s Gate lab site to confirm Damer’s findings and conduct more wet-dry cycle studies.
Nicholas Hud, a chemist at George Institute of Technology in Atlanta, USA, studies the origins of life from a slightly different perspective: he explores how DNA and RNA nucleotides originate, and he agrees that these molecules are more likely to be connected by condensation on land than in the ocean, where dry and wet cycles can occur. These reactions produce water, and when there is a lot of water around the living environment, the formation of such chemical bonds is energy-adverse. “The best places to form this structure are hot, dry places, and humid, hot environments are the least likely to form them,” Hood said. “
However, there is evidence that humid, high-temperature environments are where life originated, with heated water gushing into the sea at hydrothermal nozzles on the dark, deep seabed at temperatures only a few degrees Celsius above freezing.
In 2017, researchers found 3.77 billion-year-old fossil evidence from the ancient seabed in Quebec, Canada, showing multiple signs of thermal activity. The researchers say these unique fossil structures are similar to microbes, suggesting evidence of early life on Earth in deep-sea environments.
The chemical composition of nozzles such as limestone chimneys found in the Atlantic “Lost City” supports the survival of microorganisms.
These subsea environments can be extreme: some of the heat wave nozzles that gush over black water columns can reach temperatures as high as 400 degrees Celsius, however, if hydrothermal nozzles play an important role in breeding early life, it is likely to be a hydrothermal nozzle at the right temperature. For example, “Lost City” is a thermal zone in the mid-Atlantic, with fluid temperatures between 40 and 90 degrees Celsius flowing from the crater, known for its striking limestone chimneys, some of which are about 60 meters high.
These limestone chimneys are home to microbes that feed on a chemical reaction called serpenian rock, said Laurie Barge, astrophysicist at NASA’s Jet Propulsion Laboratory in California. “
In areas such as lost cities, chemical reactions between water and rock make the water flowing from the nozzle more alkaline than in the ocean, which contains higher concentrations of positively charged hydrogen ions. The gradient change from alkaline water to acidic water is like the difference between the positive and negative poles of a battery, and can be used as a source of chemically active energy.
To study the condition of underwater thermal nozzles, Bagg created a simulated environment in the experiment, saying: “We can simulate what nature sees. To depict the marine environment of the early Earth, she filled an upside-down glass bottle with an iron-containing but oxygen-free acidic mixture, with one end of the plastic tube passing through the narrow bottom of the glass bottle, connected to a stable alkaline solution that acted like an exhaust port.
The researchers simulated alkaline thermal nozzles in an acidic ocean to explore the chemical composition of ancient oceans, conditions that could produce chimney structures. JPL-Caltech/NASA
When Bagh and colleagues inject an alkaline port solution containing RNA nucleotides into an ocean simulation bottle, a single RNA nucleotide is connected to a short chain. The chains are only 3-4 nucleotide lengths long, but the researchers report in a 2015 study published in the journal Space Biology that the condition of deep-sea thermal nozzles may support the response to life on Earth.
For Demmer, assembling elements of life near underwater thermothermal nozzles is a huge obstacle: the vast ocean dilutes molecules so they don’t condense enough to trigger a chemical reaction. In addition, there is no “dry-wet cycle” in the underwater environment. This requires repeated evaporation to bring enough molecules together to collide with each other to form longer chains. In addition, unlike fresh water in hot springs, saltwater inhibits the formation of films and inhibits the reaction of molecules to connect together, Demmer said.
However, academics have also criticized Demmer’s theory of hot springs, with David Des Marais, an astrobiologist at NASA’s Ames Research Center, saying: “DNA and RNA chains are made up of phosphates and sugar molecules alternating, but sugar is very unstable in hot spring environments. “
It may be too early to rule out underwater “dry-wet cycles,” said Bill Brazelton, a marine microbiologist at the University of Utah in Salt Lake City. “
Current scientists may not be able to determine how life on Earth gave birth: most of earth’s earliest geological records have disappeared, and there are many speculative theories about the origin of life, in addition to hot springs and deep-sea spits on Earth. For example, new research suggests that an asteroid collision could send overheated water into the Earth’s crust, creating a hot spring-like hydrothermal system.
“I think we have to admit that early life may have gone through a lot of bumpy times in order to promote the breeding of life, ” Desmaras said. “
Researchers are using what they have learned to analyze when and where life originated on Earth, which may guide humans in their search for biological features beyond Earth. There are several promising planets in the solar system, and mysterious life forms are likely to occur on those planets.
“What NASA is really interested in is whether there is life in the ocean beneath the surface of frozen moons such as Immon 2 and Titan, ” said Bataha, a scientist at the University of California, Santa Cruz. “Scientists have evidence that there is a salty liquid ocean beneath the ice shells of the two satellites.
Pictured is water vapor gushing from Titan’s frozen surface, captured by NASA’s Cassini spacecraft, containing compounds of carbon, nitrogen and oxygen. Hydrogen in the plume is evidence of ocean hydrothermal activity beseping arcticly, similar to deep-sea nozzles on Earth.
What is interesting about these satellites is that, in addition to liquid water, their surfaces are sprayed with water columns, indicating hydrothermal activity. NASA’s Cassini space probe even found compounds containing carbon, nitrogen and oxygen, as well as amino acids that make up proteins, in Titan’s jet plumes. Cangutan and Titan attract astronomers because their seafloor activity may be similar to the thermal nozzles of our Earth’s oceans, an environment that could potentially provide chemical conditions for life.
“Even if you’re on an icy satellite, you’re going through ice freezing and melting, so I think it’s important to say that if the wet and dry cycle is important, then we should look in the solar system for any environmental conditions that might promote dehydration oscillations,” Bagh said. “
But looking for signs of ancient life, Demmer and Day defaulted to the fact that Mars is the planet more likely to have life. Analysis of deposit samples shows that hot springs and hydrothermal activity existed in ancient times on Earth, maintaining a wet and drying cycle, which is essential for the condensation reaction to breed life.
Currently, several countries have proposed a Mars exploration program, and NASA’s Perseverance rover will land at Mars’ Jezelo Crater in February 2021 to look for signs of ancient life, such as collecting minerals from rock samples. Although Mars and “Bangpas Hell” are 54.6 million kilometers apart, their environment is not very different.