How introducing microbial life to Mars can make it livable for humans

In order to build a second Earth, we need to look at how the first one was made.

How introducing microbial life to Mars can make it livable for humans
Wikimedia Commons
  • Humanity dreams of becoming an interplanetary species, but no other planet in our solar system can currently support complex life.
  • In order to make a planet like Mars hospitable for us, we'll have to engage in a massive, decades-long terraforming effort.
  • Much of what makes Earth livable, such as breathable air, tolerable temperatures, and so on, are the result of microbial activity from Earth's early history. Can we use microbial life to make the same changes on Mars?

Three billion years ago, Earth would not have been all that pleasant for humans. It was covered in active volcanoes, spewing out carbon dioxide and water vapor. Single-celled life scraped by on a diet of sulfur. Most of the atmosphere consisted of carbon dioxide, methane, and other greenhouse gases, leaving the air toxic for us and most other modern life on Earth.

Then, about 2 and a half billion years ago, something happened. With what amounts to a snap of the fingers in geologic timescales, the atmosphere was pumped full of oxygen in what we call the Great Oxygenation Event. The abundance of oxygen meant that new, more diverse kinds of life could take a hold on the young planet, such as Eukaryotes. Fast-forward a few billion years, and complicated, multicellular life like ourselves are walking around the planet.

So where did all of this oxygen come from? Today, we think that nearly all of the oxygen on Earth came from cyanobacteria, tiny, blue-green, single-celled life that had the innovative idea of using sunlight to bake water and carbon dioxide into sugar for energy — that is, photosynthesis. Unfortunately for the cyanobacteria, photosynthesis makes the unappealing byproduct of oxygen, which they throw away into their environment.

Every breathe we take, we owe to cyanobacteria, and this influx of oxygen into our environment is ultimately responsible for why modern Earth is so accommodating to life. But what Earth giveth, Earth also taketh away. Whether it's because of climate change, nuclear war, a global pandemic, or some unknown catastrophe, eventually we'll want a new home. But our closest, best hope for a new home — Mars — doesn't have any oxygen.

It doesn't have much of an atmosphere at all, really.

This said, scientists are hoping to recreate the Great Oxygenation Event on Mars much in the same way it happened on Earth; by using microbial life to build the environment for us.

Terraforming Mars with microbes

An artist's depiction of a Martian terraforming effort's progression.

Wikimedia Commons

While Mars might be different from early Earth in many ways, it does possess some key characteristics that could make a microbial terraforming project work. Mars has an atmosphere that's 95 percent carbon dioxide, which provides half of the ingredients needed for cyanobacteria to make oxygen. The other ingredient, water, is admittedly scarce on the Red Planet, but we've seen evidence that it exists. We know that ice is abundant in the poles, so much so that if we were to melt them, Mars would be covered in an 18-foot-deep ocean.

There's already some liquid water that exists on Mars, to be sure — just in very scant amounts. We've seen features on Mars called recurring slope lineae, which are dark lines that advance down the sides of hills during the Martian summer and fade away during the winter. These dark lines are thought to be flows of water that come and go with the seasons.

This image of the side of a Martian crater shows recurring slope lineae. The dark lines descending from the slope of the crater come and go with the seasons, which may indicate flowing water.

NASA

So, to terraform Mars, we would start with areas where we know liquid water exists and dump a lot of cyanobacteria there. Admittedly, it would be a bit more of a sophisticated operation than that makes it sound, but that's the gist of the idea. We would also want to include microbes that produce greenhouse gases.

Mars has the opposite problem as Earth; we want to make Mars hotter and thicken its atmosphere, so its polar ice can melt. More water means more opportunities for microbial life to do its work. Not to mention that the current climate on Mars is much too chilly for even the hardiest human — it averages at about minus 81 degrees Fahrenheit, although the temperature can vary wildly.

The idea of using microbes to kickstart a terraforming project on Mars is so promising that NASA has already begun preliminary tests. The Mars Ecopoiesis Test Bed is a proposal for a device to be included with future robotic missions to Mars. It would look something like a drill with a hallow chamber inside. The drill would bury itself in the Martian soil, preferably somewhere with liquid water. A container full of cyanobacteria would be released into the chamber, and sensors would detect whether the microbial life produce any oxygen or other byproducts.

The first phase of this project was conducted in a simulated Martian environment here on Earth, and the results were positive. But even still, there are some major challenges we'll have to meet if we want to use microbially terraform Mars on a large-scale.

Challenges

The Mars Ecopoiesis Test Bed.

NASA

Mars lacks something very necessary for life-giving planets: a magnetosphere. Mars used to have a magnetic field that protected the planet. We've found magnetized rocks on the surface indicating that this was the case, but at some point, the magnetic field just disappeared, and we don't know for certain what happened. Without a magnetosphere, the planet's surface is bombarded by solar radiation, which will make larger, more complex life difficult to sustain.

This "solar wind" also blows away the Martian atmosphere. So, even if we do coax microbial life into producing oxygen and other gasses, much of it will simply float away into space.

These images show different elements escaping from the Martian atmosphere. From left to right, the images show carbon, oxygen, and hydrogen floating away to space.

Wikimedia Commons

Fortunately, these challenges are not insurmountable. In the short term, we'll likely construct dome-like habitats to protect both us, our cyanobacteria, and our new atmosphere from the solar wind. In the long term, NASA scientists have proposed placing a powerful magnet in fixed orbit between Mars and the Sun. This magnet will redirect the solar wind, shielding the Martian atmosphere. As microbial life continues to output oxygen and greenhouse gases into the Martian atmosphere, the planet will warm up, the ice caps will melt into oceans, and Mars may very well become our second home.


U.S. Navy controls inventions that claim to change "fabric of reality"

Inventions with revolutionary potential made by a mysterious aerospace engineer for the U.S. Navy come to light.

U.S. Navy ships

Credit: Getty Images
Surprising Science
  • U.S. Navy holds patents for enigmatic inventions by aerospace engineer Dr. Salvatore Pais.
  • Pais came up with technology that can "engineer" reality, devising an ultrafast craft, a fusion reactor, and more.
  • While mostly theoretical at this point, the inventions could transform energy, space, and military sectors.
Keep reading Show less

Why so gassy? Mysterious methane detected on Saturn’s moon

Scientists do not know what is causing the overabundance of the gas.

An impression of NASA's Cassini spacecraft flying through a water plume on the surface of Saturn's moon Enceladus.

Credit: NASA
Surprising Science
  • A new study looked to understand the source of methane on Saturn's moon Enceladus.
  • The scientists used computer models with data from the Cassini spacecraft.
  • The explanation could lie in alien organisms or non-biological processes.
Keep reading Show less

CRISPR therapy cures first genetic disorder inside the body

It marks a breakthrough in using gene editing to treat diseases.

Credit: National Cancer Institute via Unsplash
Technology & Innovation

This article was originally published by our sister site, Freethink.

For the first time, researchers appear to have effectively treated a genetic disorder by directly injecting a CRISPR therapy into patients' bloodstreams — overcoming one of the biggest hurdles to curing diseases with the gene editing technology.

The therapy appears to be astonishingly effective, editing nearly every cell in the liver to stop a disease-causing mutation.

The challenge: CRISPR gives us the ability to correct genetic mutations, and given that such mutations are responsible for more than 6,000 human diseases, the tech has the potential to dramatically improve human health.

One way to use CRISPR to treat diseases is to remove affected cells from a patient, edit out the mutation in the lab, and place the cells back in the body to replicate — that's how one team functionally cured people with the blood disorder sickle cell anemia, editing and then infusing bone marrow cells.

Bone marrow is a special case, though, and many mutations cause disease in organs that are harder to fix.

Another option is to insert the CRISPR system itself into the body so that it can make edits directly in the affected organs (that's only been attempted once, in an ongoing study in which people had a CRISPR therapy injected into their eyes to treat a rare vision disorder).

Injecting a CRISPR therapy right into the bloodstream has been a problem, though, because the therapy has to find the right cells to edit. An inherited mutation will be in the DNA of every cell of your body, but if it only causes disease in the liver, you don't want your therapy being used up in the pancreas or kidneys.

A new CRISPR therapy: Now, researchers from Intellia Therapeutics and Regeneron Pharmaceuticals have demonstrated for the first time that a CRISPR therapy delivered into the bloodstream can travel to desired tissues to make edits.

We can overcome one of the biggest challenges with applying CRISPR clinically.

—JENNIFER DOUDNA

"This is a major milestone for patients," Jennifer Doudna, co-developer of CRISPR, who wasn't involved in the trial, told NPR.

"While these are early data, they show us that we can overcome one of the biggest challenges with applying CRISPR clinically so far, which is being able to deliver it systemically and get it to the right place," she continued.

What they did: During a phase 1 clinical trial, Intellia researchers injected a CRISPR therapy dubbed NTLA-2001 into the bloodstreams of six people with a rare, potentially fatal genetic disorder called transthyretin amyloidosis.

The livers of people with transthyretin amyloidosis produce a destructive protein, and the CRISPR therapy was designed to target the gene that makes the protein and halt its production. After just one injection of NTLA-2001, the three patients given a higher dose saw their levels of the protein drop by 80% to 96%.

A better option: The CRISPR therapy produced only mild adverse effects and did lower the protein levels, but we don't know yet if the effect will be permanent. It'll also be a few months before we know if the therapy can alleviate the symptoms of transthyretin amyloidosis.

This is a wonderful day for the future of gene-editing as a medicine.

—FYODOR URNOV

If everything goes as hoped, though, NTLA-2001 could one day offer a better treatment option for transthyretin amyloidosis than a currently approved medication, patisiran, which only reduces toxic protein levels by 81% and must be injected regularly.

Looking ahead: Even more exciting than NTLA-2001's potential impact on transthyretin amyloidosis, though, is the knowledge that we may be able to use CRISPR injections to treat other genetic disorders that are difficult to target directly, such as heart or brain diseases.

"This is a wonderful day for the future of gene-editing as a medicine," Fyodor Urnov, a UC Berkeley professor of genetics, who wasn't involved in the trial, told NPR. "We as a species are watching this remarkable new show called: our gene-edited future."

Quantcast