Exotic Subterranean Life On Earth

"Exploring the deep subsurface is akin to exploring the Amazon rainforest. There is life everywhere, and everywhere there's an awe-inspiring abundance of unexpected and unusual organisms."
"Molecular studies raise the likelihood that microbial dark matter is much more diverse than what we currently know it to be, and the deepest branching lineages challenge the three-domain concept introduced by Carl Woese in 1977. Perhaps we are approaching a nexus where the earliest possible branching patterns might be accessible through deep life investigation."
Mitch Sogin, Marine Biological Laboratory Woods Hole, USA

"Ten years ago, we knew far less about the physiologies of the bacteria and microbes that dominate the subsurface biosphere. Today, we know that, in many places, they invest most of their energy to simply maintaining their existence and little into growth, which is a fascinating way to live."
"Today too, we know that subsurface life is common. Ten years ago, we had sampled only a few sites - the kinds of places we'd expect to find life. Now, thanks to ultra-deep sampling, we know we can find them pretty much everywhere, albeit the sampling has obviously reached only an infinitesimally tiny part of the deep biosphere."
Karen Lloyd, University of Tennessee at Knoxville, USA

Anunidentified nematode, found in a gold mine in South Africa, lives nearly 1.5 kilometers below the surface. Gaetan Borgonie, Extreme Life Isyensya, Belgium

"Our studies of deep biosphere microbes have produced much new knowledge, but also a realization and far greater appreciation of how much we have yet to learn about subsurface life."
"For example, scientists do not yet know all the ways in which deep subsurface life affects surface life and vice versa. And, for now, we can only marvel at the nature of the metabolisms that allow life to survive under the extremely impoverished and forbidding conditions for life in deep Earth."
Rick Colwell, Oregon State University, USA

"Discoveries regarding the nature and extent of the deep microbial biosphere are among the crowning achievements of the Deep Carbon Observatory. Deep life researchers have opened our eyes to remarkable vistas - emerging views of life that we never knew existed."
Robert Hazen, Senior Staff Scientist, Geophysical Laboratory, Carnegie Institution for Science, and DCO Executive Director

In search of life under the sea floor   EOS

New discoveries of life forms not on Earth but in Earth are being unearthed as it were with surprising conclusions. Biologists decades ago would never have believed that life might exist without sunlight, without oxygen, without moderating temperatures, without protection from the sheer weight of the mass of the Earth. It is known now with a thoroughness perhaps never before imagined that the internal deep subsurface chemistry of this planet supports life such as microbes dwelling deep within the Earth.

Scientists read into their presence a tantalizing hint of comparison with our own common ancestors which were surface dwellers at a time when Earth's early chemistry before abundant oxygen was available billions of years ago were similarly challenged in a deficit of life conditions, in a similarity to the deep subsurface biosphere now known to exist and thrive; leading to the hypothesis that quite possibly life on earth began deep within the Earth, filtering its way to the surface eventually.

The mysterious creatures such as Geogemma barossii which lives deep within our world in water furiously boiling at 120 degrees, an organism that nature adapted to live at extreme heat. This microbe is one of many that thrive in a massive subterranean habitat teeming with life forms. In a ten-year period, science has progressed in its investigation of subterranean life on our planet as investigators seeking to make sense of hidden habitats came together under the auspices of the Deep Carbon Observatory.

Remotely operated underwater vehicles, collection tubes, high-tech drills, DNA technology and computer modelling have all aided researchers as they explore volcanoes, diamond mines, deep-sea hot springs, underwater mud volcanoes and all manner of extreme geological sites underneath oceans and continents; in so doing, turning the world upside-down in terms of the vast proliferation of life forms.

Deep Carbon Observatory

Consider this: an estimated 200 to 600 octillion (octillion: 1 followed by 27 zeroes) microbes live under the world's continents with even greater numbers thriving beneath the floor of the seas -- all of which weigh the equivalent of some 200 million blue whales; a bulk weight scale far greater than the 7.5 billion humans would comprise. The sheer diversity of these subterranean creatures challenges the diversity of surface life even as most underground organisms have yet to be discovered, much less characterized.

Buried beneath deep within sediments or the sulfuric crust in the seafloor, or encased within granite, basalt, sandstone or clay beneath continents, microbial communities vary; some fungi and multicellular organisms resembling insects and worms exist deep underground. Some are scavengers who thrive on photosynthesis leftovers from the surface, buried for up to hundreds of millions of years.

There are microbes that breathe uranium, expelling waste expressed as tiny crystals. If nutrient availability becomes diminished, microbes become dormant, with subsurface microbes reproducing only once every 30 years; in various instances it can take tens to thousands of years to replace an old population with a new one, where the chemistry in the deep subsurface supports life.

Some researchers hypothesize the possibility that what occurs in the subsurface might reflect life elsewhere in the solar system; Mars or Europa: "Could there be a deep biosphere on these other worlds?" muses Robert Hazen, mineralogist at George Mason University in Virginia, and director of the observatory. Until such time as such a possibility is explicated by new discoveries what has been seen to date is "providing us with a vivid new way of thinking about 'what is life'?"

Flatiron Institute