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.

  • 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

Wikimedia Commons

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

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.

NASA

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.

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

NASA

The Mars Ecopoiesis Test Bed.

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.

Wikimedia Commons

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.

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.


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Want to forge stronger social bonds? Bring beer.

New research shows that a healthy supply of locally-sourced beer helped maintain Wari civilization for 500 years.

Culture & Religion
  • A new analysis of an ancient Wari brewery suggests chicha helped maintain the civilization's social capital for hundreds of years.
  • Civilizations throughout the ancient world used alcoholic drinks to signify kinship, hospitality, and social cohesion.
  • The researchers hope their findings will remind us of the importance in reaffirming social institutions and sharing cultural practices — even if over coffee or tea.

Beer is history's happiest accident. Though the discovery probably happened much earlier, our earliest evidence for beer dates back roughly 13,000 years ago. Around this time, the people of the Fertile Crescent had begun to gather grains as a food source and learned that if they moistened them, they could release their sweetness to create a gruel much tastier than the grains themselves.

One day a curious — or perhaps tightfisted — hunter-gatherer hid his gruel away for a safekeeping. When he returned, he found the bowl giving off a tangy odor. Not one to waste a meal, he ate it anyway and enjoyed an unexpected, though not unpleasant, sensation of ease. By pure happenstance, this ancestor stumbled upon brewing.

That's one possible origin story, but we know that our ancestors learned to control the process, and beer took a central role in Fertile Crescent civilizations — so central that Professor Patrick McGovern, a biomolecular archaeologist at the University of Pennsylvania, argues that beer, not bread, incentivized hunter-gatherers to relinquish their nomadic ways.

Beer may also be proof of a God who wants us to be happy (Dionysus?), because the beverage* would be independently rediscovered by peoples across the ancient world, including those in China and South America.

One such peoples, the pre-Inca Wari Civilization, made beer, specifically chicha de molle, a critical component in their religious and cultural ceremonies. In fact, a study published in Sustainability in April argues that the role was so important that beer helped keep Wari civilization intact for 500 years.

Brewing social capital

Twenty years ago, a team of archaeologists with the Field Museum of Natural History, Chicago, discovered a brewery in Cerro Baúl, a mesa in southern Peru that served as an ancient Wari outpost. The brewery contained original equipment, clay storage vessels, and compartments for milling, boiling, and fermentation.

The team recently analyzed these on-site vessels to uncover the secrets of the Wari brewing process. Removing tiny amounts of material found in the spaces between the clay, they were able to reconstruct the molecules of the thousand-year-old drink. They then worked alongside Peruvian brewers to recreate the original brewing process.**

Their molecular analysis revealed several key features of the beer: The clay used to make the vessels came from a nearby site; many of the beer's ingredients, such as molle berries, are drought resistant; and though alcoholic, the beer only kept for about a week.

These details suggest that Cerro Baúl maintained a steady supply of chicha, limited by neither trade nor fair weather, and became a central hub for anyone wishing to partake. The Wari would likely make such trips during times of festivals and religious ceremonies. Social elites would consume chicha in vessels shaped like Wari gods and leaders as part of rituals attesting to social norms and a shared cultural mythology and heritage.

"People would have come into this site, in these festive moments, in order to recreate and reaffirm their affiliation with these Wari lords and maybe bring tribute and pledge loyalty to the Wari state," Ryan Williams, lead author and head of anthropology at the Field Museum, said in a release. "We think these institutions of brewing and then serving the beer really formed a unity among these populations. It kept people together."

The Wari civilization was spread over a vast area of rain forests and highlands. In a time when news traveled at the speed of a llama, such distinct and distant geography could easily have fractured the Wari civilization into competing locales.

Instead, the researchers argue, these festive gatherings (aided by the promise of beer) strengthened social capital enough to maintain a healthy national unity. This helped the Wari civilization last from 600 to 1100 CE, an impressive run for a historic civilization.

Bringing people together (since 10,000 BCE)

A Mesopotamian cylinder seal shows people drinking beer through long reed straws. Image source: Metropolitan Museum of Art.

Of course, the Wari weren't the first civilization to use beer to reaffirm bonds and maintain their social fabric. Returning to the Fertile Crescent, Sumerians regarded beer as a hallmark of their civilization.

The Sumerian Epic of Gilgamesh tells of the adventures of the titular hero and his friend Enkidu. Enkidu beings as a savage living in the wilderness, but a young woman introduces him to the ways of civilization. That orientation begins with food and beer:

"They placed food in front of him,
They placed beer in front of him,
Enkidu knew nothing about eating bread for food,
And of drinking beer he had not been taught.
The young woman spoke Enkidu, saying:
"Eat the food, Enkidu, it is the way one lives.
Drink the beer, as is the custom of the land."
Enkidu ate the food until he was sated,
He drank the beer — seven jugs! — and became expansive
and sang with joy.
He was elated and his face glowed.
He splashed his shaggy body with water
and rubbed himself with oil, and turned into a human
."

Tom Standage, who recounts this scene in his History of the World in 6 Glasses, writes: "The Mesopotamians regarded the consumption of bread and beer as one of the things that distinguished them from savages and made them fully human." Such civilized staples not only demarcated their orderly life from that of hunter-gatherers, they also served a key role in their culture's unifying mythology.

Furthermore, Standage notes, Sumerian iconography often shows two people sipping from waist-high jars through reed straws. The earliest beers were consumed in a similar fashion because technological limitations prevented baking individual cups or filtering the beverage. But the Sumerians had the pottery skills to make such cups and filter the dregs. That they kept the tradition suggests that they valued the camaraderie brought by the experience, a sign of communal hospitality and kinship.

The ancient Greek's similarly used alcohol as a means of maintaining social and political relationships — though their drink of choice was wine.

During symposiums, upper-class Greek men would gather for a night of drinking, entertainment, and social bonding. In Alcohol: A history, Rod Phillips notes that symposiums were serious affairs where art, politics, and philosophy were discussed throughout the night and could serve as rites of passage for young men. (Though, music, drinking games, and sex with prostitutes may also be found on the itinerary.)

Of course, we can amass social capital without resorting to alcohol, which has been known to damage social relationships as much as improve them.

In the 17th century, London's coffeehouses stimulated the minds of thinkers with their caffeine-laden drinks, but also served as social hubs. Unlike the examples we've explored already, these coffeehouses brought together people of different backgrounds and expertise, unifying them in their pursuit of ideas and truths. Thus, coffeehouses can be seen as the nurseries of the Enlightenment.

Relearning ancient lessons

The Field Museum archaeologists hope their research can help remind us the importance social institutions and cultural practices have in creating our common bonds, whether such institutions are BYOB or not.

"This research is important because it helps us understand how institutions create the binds that tie together people from very diverse constituencies and very different backgrounds," Williams said. "Without them, large political entities begin to fragment and break up into much smaller things. Brexit is an example of this fragmentation in the European Union today. We need to understand the social constructs that underpin these unifying features if we want to be able to maintain political unity in society."

So, grab a beer or coffee or tea, spend some time together, and raise a glass. Just try not focus too much on whether your friend ordered Budweiser's swill or an overpriced, virtue-signaling microbrew IPA.

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