Surviving on hydrogen alone? Earth's glacial microbes offer us a new direction in the search for extraterrestrial life
Summary: Glacier research has found that microbes can survive in low-temperature hydrogen environments without the need for sunlight, which used to be considered essential elements. The Dragon probe, which is expected to launch to Titan in 2026, may be expected to find life on the planet with a surface temperature of -290 degrees Celsius.
How is life formed? Then, how do you survive and reproduce? Astronomers have been searching for answers to this question for decades, but they have only figured out a fraction of the puzzle. They claim that to understand how life formed on our planet, we must look to the universe and look for answers from the universe.
When we look for life on different planets, we have to accept the reality that life on other planets may not look exactly like life on Earth. If they do exist, extraterrestrial life on Mars, Enceladus, or distant exoplanets will thrive in a completely different environment than ours.
A new study suggests that microbes may be able to survive on hydrogen alone, without scientists believing that the basic element of life is sunlight.
When it comes to finding life on other planets, astronomers can only use earth that we are familiar with and have life as a simulation reference.
Therefore, when looking for environmental conditions suitable for life, they will refer to some elements that are considered essential for life on Earth.
To be fit for life, a planet needs water, an atmosphere, energy, and most importantly, the right amount of heat, radiation, and light from its parent star.
Our solar system is habitable, in part because of the good properties of its parent star, the Sun.
NASA's Cassini spacecraft took this picture of Titan, Saturn's largest moon.
It's an icy world that is thought to have probably chemicals that are suitable for life.
(Image source: NASA/Jet Propulsion Laboratory/Institute of Space Science)
But team members of the new study believe that life on other planets may not require light to form and survive. Instead, their research suggests that life may be able to survive on hydrogen alone.
To reach this conclusion, they measured hydrogen concentrations in glacial meltwater in southern Iceland. Comparing the two scenarios: glacial meltwater passing through basalt rocks and flowing through carbon-based rocks, they found that the former had higher concentrations of hydrogen in the meltwater.
According to the study, because meltwater interacts with mineral surfaces — which happens when glaciers touch Earth's bedrock surface — this process appears to produce chemical resources that microbes can use as energy needed to survive and reproduce.
So even with the lack of sunlight, microbes can find another way to survive.
Interestingly, the metabolic pathways seen in these microbes reflect life found in other extreme environments— albeit in a completely different sense. They have the same characteristics as bacteria that live in extreme heat or acidic environments, for example, thermophilic bacteria that live in the Great Prism Springs of Yellowstone National Park.
The Prism Spring is another extreme environment in which life finds a way to survive and reproduce—without all the usual ingredients. (Image credit: Universal Image Group/Getty Images)
These extreme life forms, and their harsh conditions, cluster in areas of survival, prompt astronomers to search for life elsewhere in the universe. Since the discovery of the first exoplanet orbiting non-Solar stars in 1992, astronomers have found signs that extraterrestrial life may be thriving on other planets.
So far, scientists have discovered more than 4,000 exoplanets. The few that exist in the so-called "blonde zone"—the space between a star and a planet—are considered ideal regions for life to be born and reproduce. In our own solar system, very close to Earth, scientists have found signs of phosphine in the Venus Cloud — a small hint of biochemistry in its underclass. On Mars, scientists have discovered water — water is one of the key components of life, like sunlight — suggesting that Mars may have once bred life.
But these are only hints. We haven't really found life on other planets yet.
The scientists behind the new study argue that if life can survive and reproduce in Iceland's glaciers, it could also survive on frozen exoplanets, in similar environments. Soon, NASA plans to launch Dragonfly, a small helicopter-like spacecraft that will scan Titan's atmosphere in search of life signals. Titan, the largest of Saturn's moons, has an extremely cold surface temperature of -290 degrees Fahrenheit. Scheduled to launch in 2026, Dragonfly will look for biological signals wrapped in Titan Ice — biological signals that are only generated under the influence of living organisms.
In environments that lack photosynthesis, such as on early Earth, or in contemporary dark underground ecosystems, life is supported by chemical energy. How, when and where chemical nutrients released from the Earth's crust fuel the chemical synthetic biosphere is fundamental to understanding the distribution and diversity of life in geological periods today and past. When water interacts with active constituents on the surface of minerals, such as silicate radicals and ferrous, hydrogen (H2) is formed, which is a powerful reducing agent.
The active ingredient on the surface of this mineral is continuously produced due to the physical crushing of the bedrock by glaciers. Here, it should be noted that the dissolved hydrogen concentration in the meltwater of the basalt glacier catchment area rich in iron and silicate minerals is one order of magnitude higher than in the meltwater of the carbonate-dominated catchment area. Consistent with higher hydrogen (H2) abundances, sediment microbial communities in basalt catchments have significantly shorter durations, faster rates of pure hydrogen (H2) oxidation, and dark carbon dioxide (CO2) fixation than carbonate catchments. It is shown that in the basalt catchment area, hydrogen (H2) is suitable for use as a reducing agent.
Enrichment and culture of basalt deposits containing hydrogen H2, carbon dioxide CO2 and trivalent iron bred a chemo-autotrophic population associated with iron-reducing red cultivars. Its metabolism, previously thought to be limited to (hyper)thermophilic bacteria and acidophiles. These findings point to the importance of physical and chemical weathering processes in producing, supporting, and synthesizing primary nutrients. In addition, it should be noted that differences in the mineral composition of bedrock can affect the supply of nutrients such as hydrogen (H2), which in turn affects the diversity, abundance and activity of microbial communities.
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