- Is there life on Mars? We still don’t know for sure.
- Microbial life could exist below dusty ice deposits, a new study from NASA said.
- Pools of liquid water below the ice and sunlight passing through the translucent ice could support photosynthesis and microbial life, similar to what happens on Earth.
Microbial life on Mars?
We don’t know for sure if Mars ever had – or even still has – any kind of life. The surface of Mars today is hostile for any form of life, even microbes. Some scientists say microbes could possibly be found underground, where they would be more protected from the harsh conditions on the surface. Now there’s another idea. A new NASA study suggested that beneath ice deposits would be a good place to look for life. The researchers said on October 17, 2024, that meltwater underneath dusty ice could be an ideal home for microbes. There would also still be enough sunlight passing through the translucent ice for photosynthesis to occur.
The researchers published their peer-reviewed findings in Communications Earth & Environment (Nature) on October 17, 2024.
Could water ice on the Martian surface hide microscopic life below?
Ecosystems found within Earth’s icy regions are inspiring scientists to ask new questions: pic.twitter.com/oUrYPB9uje
— NASA Mars (@NASAMars) October 17, 2024
Life on Mars? Try looking under ice
Water is essential for life on Earth. So it makes sense to “follow the water” on Mars as well. The problem is that water can’t remain on the surface due to the extreme cold and thin atmosphere. At most, there are small amounts of temporary salty brines in the soil. There may be liquid water much deeper down in the crust, but too deep for rovers or future astronauts to reach.
But there’s another possibility. On Earth, pools of meltwater can exist beneath layers of ice (or on top, since the atmosphere is much thicker). The same could be true for Mars as well. There are plenty of ice deposits, especially at the poles. Dusty ice in particular would be ideal for such meltwater to exist.
Using computer modeling, the researchers found that for some surface ice deposits on Mars, enough sunlight could filter through the translucent ice to support photosynthesis. There should also be some meltwater beneath the ice, similar to Earth.
Lead author Aditya Khuller, at NASA’s Jet Propulsion Laboratory in La Cañada Flintridge, California, said:
If we’re trying to find life anywhere in the universe today, Martian ice exposures are probably one of the most accessible places we should be looking.
Dusty ice and photosynthesis
According to the new study, ice deposits with some dust mixed in would be ideal. The darker dust would absorb more sunlight, helping ice at the bottom of the deposits to melt. This same process happens on Earth as well. On the surface, ice will sublimate directly into gas in the cold, thin atmosphere. But below a layer of ice, it can become liquid.
How does this happen on Earth? As co-author Phil Christensen at Arizona State University in Tempe, Arizona, noted:
This is a common phenomenon on Earth. Dense snow and ice can melt from the inside out, letting in sunlight that warms it like a greenhouse, rather than melting from the top down.
In earthly ice deposits, particles of dust – known as cryoconite – can create holes in ice, called cryoconite holes. The dust particles melt the ice where they land. The holes gets a bit deeper each summer when it’s warmer. When the particles eventually stop sinking into the ice, they form pools of meltwater around them. And indeed, those small pools become thriving ecosystems.
The most likely locations for such dusty ice deposits would be in the Martian “tropics,” between 30 degrees and 60 degrees latitude, in both the northern and southern hemispheres.
In addition, the study found enough sunlight could pass through the ice to support photosynthesis as deep as 9 feet (3 meters). Not only would the overlaying ice help keep the water pools liquid, it would also protect any organisms from the deadly radiation on the surface.
With both liquid water and photosynthesis being theoretically possible, these Martian ice deposits would be a good place to search for evidence of current, or past, microbial life.
Other possible Martian water
Last August, scientists said there is now evidence for an ocean’s worth of liquid water deep underground in the Martian crust. The water would be 7 to 13 miles (11 to 20 km) below the surface. This is deep enough that, according to the study, temperatures could keep the water liquid. No ice cover needed. But that also means it is inaccessible for study by any rovers or even future astronauts in the foreseeable future.
There is also the tentative discovery of lakes of water beneath the south polar ice cap. That has been a subject of ongoing debate, however.
Bottom line: A new NASA study said microbial life on Mars could exist in pools of liquid water beneath dusty ice deposits, with enough sunlight for photosynthesis.
Source: Potential for photosynthesis on Mars within snow and ice
Via NASA
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