Biologists who study extremophiles are dramatically expanding our sense of just how amazingly resilient microorganisms can be — insights that have serious implications in our search for extraterrestrial life. At the same time, these hardy microbes are also inspiring synthetic biologists to create their own strains of life, that might be capable of living in harsh, off-planet conditions.
But as a recent article by Tanya Lewis in Wired points out, while the prospect of kindling life on another planet holds promise for future colonization efforts, there are some important scientific and ethical questions that need to be answered first.
There's no question that certain microbes are very hard to kill. We know that microbes can live in the cracks of rocks near scorchingly hot undersea volcanoes, the driest deserts, the highest altitudes, and in extremely primitive environments. We also know that some microbes can withstand lack of oxygen, and the rigours of space.
And as Tanya Lewis writes, these microbial outliers have given prospective synthetic biologists a wider sense of what's possible. And indeed, the advent of synthetic biology, with its potential for custom designed artificial life, has inspired a number of initiatives and projects, including the International Genetically Engineered Machines (IGEM) challenge — an annual competition for students who are actively hacking living cells in an effort to create something entirely new.
The Hell Cell
And these students are not thinking small. Some are looking to create a super-extremophile bacterium that can withstand the most severe conditions — including those experienced on Mars. Lewis writes:
The Hell Cell includes genetic modules, or BioBricks, based on DNA from a variety of ultra-tough organisms, including a cold-resistant species of Siberian beetle that makes "antifreeze" proteins, a radiation-resistant bacterium that sequesters large amounts of the element manganese, and E. coli, which produces a nutrient that confers cold and drought resistance. The team is also investigating heat- and acid-tolerance mechanisms that could be useful in other planetary environments.
While they're currently experimenting with E. coli, BioBricks can be mixed and matched in other species, tailoring new strains to particular conditions. "You go into nature and find genes, and then you can recombine them into circuits that you cannot find in nature," explained Andre Burnier, one of the team's mentors and a lab technician at NASA's Ames Research Center.
To be really successful, the bacteria must do more than just survive on Mars. They need to perform functions useful for establishing a human colony one day. In addition to the Hell Cell suite, the team is developing bacteria that could extract minerals from Martian sediment or recycle rare metals from spacecraft electronics.
A central impetus behind the desire to create a Martian Hell Cell is the suggestion that these microbes may help humans colonize Mars. For example, the microbes could assist in the production of food, medicine, and building materials. And used en masse, these microorganisms could also be made to convert planetary elements into something more useful for humans, such as oxygen.
A fundamental problem with this prospect, however, is that we risk contaminating Mars. The introduction of human-made lifeforms on Mars would have serious implications in our efforts to find pre-existing signs of life. It would essentially spoil the sample and put all subsequent analyses into question.
And as NASA's current Curiosity mission shows, there's still lots for us to learn. Despite the fact that we have yet to discover life on Mars, an increasing number of signs point to the possibility that it's there.
New Scientist's Michael Brooks recently pointed out that NASA's Viking mission may have actually found evidence of life on Mars in 1977 — and that Curiosity could be the rover to prove it. Specifically, some scientists are arguing that the discovery of carbon-based molecules in the Martian soil could indicate the presence of one type of bacteria.
Similarly, Roger Highfield reported in The Telegraph back in 2007 that the Viking mission may have detected signs of an unprecedented life form based on hydrogen peroxide. An analysis by Joop Houtkooper from Justus-Liebig-University in Giessen, Germany, suggests that 0.1% of the Martian surface could be biological in origin — an amount that's comparable to biomass found in some Antarctic permafrost.
And of course, there was the inconclusive discovery of a microbial lifeform on a Martian meteorite found in Antarctica back in 1996.
These suggestions may or may not pan out, but it's clear that we're quite a ways off from having a definitive answer. Consequently, prior to any introduction of synthetic life on Mars, we need to explore and exhaust all avenues as it pertains to the search for life on the Red Planet.
Such a discovery would not just prove monumental from an historical and existential perspective, it would also yield vital clues about the formation and resiliency of life in the cosmos. Finding life on Mars could prove to be the most important scientific discovery we ever make — so let's not ruin it. There'll be a time for synthetic life later.
Top image via Jan Kaliciak/Shutterstock.com. Inset images via NASA, DiscoveryNews.