The powerful earthquake that shook the Earth about 3.8 billion years ago ripped apart the crust, allowing chemical reactions to unfold deep within the fractured rock.These responses are caused by seismic activity, water and near-boiling temperaturea new study suggests, may have provided oxygen for some of the world’s earliest life forms.
This oxygen is packaged in hydrogen peroxide (H2O2), which contains two hydrogen atom Two oxygen atoms are bound together, according to research published Monday (August 8) in the journal Nature Communications (opens in new tab)Perhaps best known as a preservative, hydrogen peroxide is of course toxic to organisms, but once broken down it remains a useful source of oxygen enzyme Or through reactions that take place at high temperatures, Jon Thieling, senior author of the study and senior lecturer in geochemistry and geomicrobiology at Newcastle University, UK, told Live Science.
Now, in laboratory experiments, Telling and his colleagues have discovered a way in which large amounts of hydrogen peroxide may form early on. Earth Thus a potential source of oxygen for some of the earliest living things on Earth.These reactions occur most efficiently in temperature The researchers found that small amounts of H2O2 are still produced near the boiling point of water — 212 degrees Fahrenheit or 100 degrees Celsius — but at temperatures below 176 degrees Fahrenheit (80 degrees Celsius).
Notably, these temperatures overlap with the temperature ranges of thermophiles and hyperthermophiles – meaning thermophiles bacteria And archaea — known to thrive, Telling said. The common ancestor of all life on Earth is thought to have also evolved to live in hot environments, so in theory this mysterious ancestral creature could have been influenced by hydrogen peroxide that formed deep within the Earth’s crust.
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Importantly, because hydrogen peroxide destroys fat, protein and DNA of cellEarly organisms, if present in their environment, needed strategies to “detoxify” the disease, said Lynn Rothschild, a senior research scientist at NASA’s Ames Research Center in California, who was not involved in the new study. a compound.Hydrogen peroxide is also a natural product photosynthesisso in order to evolve the ability to photosynthesize, organisms may first need to be able to process H2O2.
“Before aerobic photosynthesis could occur, there must have been a source of reactive oxygen species on the early Earth” — including hydrogen peroxide,” Rothschild told Live Science.
deep in the crust
Previous (opens in new tab) study (opens in new tab)Include Rothschild lab-led work (opens in new tab)suggesting that minerals thought to be present in the early Earth’s crust could be a potential source of hydrogen peroxide and therefore oxygen.
Some of these experiments involved crushing rocks under specific conditions and then exposing those crushed rocks to water. This sequence of events mimics, on a small scale, the physical stress rocks experienced in areas of early tectonic activity, where the crust cracked open and water could seep inside.When the Earth was less than a billion years old, there was no large crust on Earth that slipped past the mantle because tectonic plate Moving around the world today, Telling said.However, the crust at that time was still buckling and cracking locally because of volcano Activity and interactions between much smaller chunks of Earth’s crust, he said.
Although past experiments have suggested that this early tectonic activity may have produced hydrogen gas (a component of hydrogen peroxide) and fully formed hydrogen peroxide, the studies yielded only small amounts of these compounds. In their new study, Telling and his colleagues conducted similar experiments, but exposed crushed rock to a wider range of temperatures and for longer periods of time — up to a week. Based on past research, they suspect this approach may increase hydrogen peroxide production.
In their rock-shattering experiments, the team used granite, a type of rock found in continental crust, as well as basalt and peridotite, which may have been abundant in the oceanic crust of early Earth. They ground the rocks to a fine powder in an oxygen-free container, carefully transferred the crushed rock to a sealed bottle, added water, and heated it.
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As rock dust reaches temperatures near boiling point, the “defects” in its constituent minerals become increasingly unstable and more likely to react with water. Specifically, these defects include “peroxy bonds,” or places where two oxygen atoms bond together in a mineral’s crystal structure, typically only with the element silicon. These defects can be introduced into the crystal if water is inadvertently added to the crystal structure as it forms, Telling said.
“When these rocks containing these peroxy bonds are stressed, these defects actually dislocate,” he explained. “They can move through the crystal structure to the surface, and then they can start interacting with the water,” an interaction that eventually produces hydrogen peroxide.
These results suggest that hydrogen peroxide may have been a common feature of the environment, at least in regions where the early Earth was shaken by earthquakes and baked at high temperatures. That said, the experiments couldn’t capture the exact rate or scale at which these H2O2-producing reactions occurred on early Earth, Telling noted.
“Look at how common this phenomenon is” and how hydrogen peroxide affects evolution Rothschild said he studies how life arose and evolved on early Earth and elsewhere in the galaxy. That is, H2O2 did not need to be present in all environments on the early Earth to influence the evolution of life on Earth. If you’re a tiny microbe with a diameter of just a few micrometers, you’re only affected by the chemicals in your environment anyway.
“Honestly, it’s enough if you have reactive oxygen nearby,” Rothschild said.This early exposure to ambient H2O2 may have provided the necessary ‘training’ for organisms that evolved into cyanobacteria, blue-green algae Responsible for injecting oxygen into Earth’s atmosphere, which shaped the course of our planet’s history, she said.
Originally published on Live Science.