Clandestine Colossus

Recent research conducted over a span of 10 years by 1200 scientists from 52 countries (that's one hell of a collaboration!) has discovered a vast subterranean ecosystem that is almost beyond belief in its size and mass. It is in the form of microbes that likely weigh somewhere between 10 and 25 billion tonnes. That's several hundred times the combined weight of all of us human beings! Just try to wrap your head around the fact that all these tiny, one-celled critters outweigh Homo sapiens several hundred times over—and they are all below the planet's surface, out of sight! We like to believe that we surface creatures are what it's all about, as we walk, swim, and fly across the crust of Earth.

These microbes live in conditions that we deem hostile to life, yet they prosper in extremely hot locations (up to 122^o C or 250^o F, like inside an oven), with no light, under intense pressures, and with minuscule nutrition. Some of their life spans are measured in geologic times, their pace is so slowed down. They are alive and do metabolize, but use such little energy that they live for millennia and appear to be in stasis. Their movement can be measured in centuries—triggered by tectonic plate shifts, earthquakes, or volcanic eruptions. At first glance, they would appear not even to be alive. We already know that microbes—bacteria and archaea—dominate on the Earth's surface, but these findings show that less than 30% of all the planet's microbes live on the surface—the vast majority is hidden.

The scientists who made this discovery did so by creating boreholes up to 5 km (3 miles) deep. The latest types of microscopes were also employed. Since the underground microbes are buried so deeply, they live in a pristine world—as yet uncontaminated by humans. As we foul the planet's surface, they continue to live beyond the reach (so far) of our harmful technologies.

These findings raise some intriguing questions about life on Earth—and possibly elsewhere. Where and how did life begin on our planet? Did it originate at the surface and later migrate downward or did it start at depths and later move upwards? What do we make of critters whose metabolism is so slow that they endure for millennia? Maybe these microbes could be identified by this study as living, because all life on Earth has similar properties and the scientists recognized some familiar features. 
 
What might this discovery say about examining possible life forms on another planet or even moons of our solar system, where life there may be of a very different chemistry or live a much slower existence—so slow that we may not even recognize them as living? If humans continue their reckless ways, the environment on Earth's surface may become unlivable for most species. If that happens, are these underground microbes—this clandestine colossus—waiting to surface one day and reinhabit our planet?

There are undoubtedly many other questions that could arise, as we continue to explore and characterize this vast underground ecosystem. We keep making discoveries that broaden our understanding of the various forms and conditions of life. It is opening us up to possibilities that we recently had no idea existed. What new discoveries await us—here on Earth or out there?