TINY STARS ON THE PLANET MARS: WHERE GEOMICROBIOLOGY IS LEADING THE SEARCH FOR EXTRATERRESTRIAL LIFE

On any Saturday afternoon of my youth, I could tune in to a bad old science fiction movie on TV and see alien life glistening with green slime creeping slowly toward the hero. Oh, if it were only really that easy to detect alien life! But in the extreme environments that capture the attention of astrobiologists, the prey is miniscule, the biomass is often negligible, the organisms may be living at a glacially slow pace, and the mineral environment does its best to befuddle our observations. Into this difficult picture has come a wondrous blending of many sciences – the field of Geomicrobiology. This is a picture hardly recognizable to our predecessors of just a generation ago.

Geomicrobiology has exploded onto the scene over the past several decades splashing across biology, mineralogy, geochemistry, and other disciplines knitting them together to provide a more understandable picture of the biological/abiological interfaces where geomicrobes spend their time. The inextricability of microorganisms with so many processes in the environment no longer comes as a shock. In fact, it is a wonder that there are any abiological processes at all at on a planet whose circum-crustal environment is as “infested” as ours! The tendency of microorganisms and their biofilm to “self-fossilize” as they grow is a habit that may help us find the biosignatures of their alien cousins on future space missions.

With the blending of the fields that comprise geomicrobiology, has come access to a dazzling spectrum of instruments and techniques that we can use to stalk the elusive extremophiles. From molecular techniques to microprobes, we are becoming ever more capable of peeking into hidden aspects of the lives and ultimate fate of the tiny creatures we study. Geomicrobiology has thus become a major player in a great Dress Rehearsal in our quest to detect the presence of extant or extinct extraterrestrial life. This rehearsal must take place here on Earth, but the star performances will happen beyond here on Mars and Europa and perhaps even more exotic planetary bodies. Though the conditions in extreme places on Earth only represent a small fraction of our planet, they may be the dominant condition on other bodies. Thus, geomicrobiology is helping us to stretch our imaginations far enough to be prepared to recognize what we may find some day amongst the stars.