Amazing stuff! What little do we still know about life on Earth!
"Barely living "zombie" bacteria and other forms of life constitute an immense amount of carbon deep within Earth's subsurface - 245 to 385 times greater than the carbon mass of all humans on the surface, according to scientists nearing the end of a 10-year international collaboration to reveal Earth's innermost secrets. ..."
"... Researchers compared more than 1000 samples from 50 marine and terrestrial ecosystems and found that, true to prior beliefs, the deeper you dig on land, the lower the diversity of life. But under the seafloor, all bets are off. Samples from nearly 500 meters below the bottom of the ocean were full of weird microbes. “We show that in some subsurface environments, the diversity can easily rival, if not exceed, diversity at the surface,” ... “We can now appreciate that perhaps half the microbial diversity on Earth is in the subsurface." ..."
"Which microbes thrive below us in darkness – in gold mines, in aquifers, in deep boreholes in the seafloor – and how do they compare to the microbiomes that envelop the Earth’s surfaces, on land and sea?
The first global study to embrace this huge question, conducted at the Marine Biological Laboratory (MBL), Woods Hole, reveals astonishingly high microbial diversity in some subsurface environments (up to 491 meters below the seafloor and up to 4375 m below ground). ..."
From the abstract:
"Subsurface environments are among Earth’s largest habitats for microbial life. Yet, until recently, we lacked adequate data to accurately differentiate between globally distributed marine and terrestrial surface and subsurface microbiomes. Here, we analyzed 478 archaeal and 964 bacterial metabarcoding datasets and 147 metagenomes from diverse and widely distributed environments. Microbial diversity is similar in marine and terrestrial microbiomes at local to global scales. However, community composition greatly differs between sea and land, corroborating a phylogenetic divide that mirrors patterns in plant and animal diversity. In contrast, community composition overlaps between surface to subsurface environments supporting a diversity continuum rather than a discrete subsurface biosphere. Differences in microbial life thus seem greater between land and sea than between surface and subsurface. Diversity of terrestrial microbiomes decreases with depth, while marine subsurface diversity and phylogenetic distance to cultured isolates rivals or exceeds that of surface environments. We identify distinct microbial community compositions but similar microbial diversity for Earth’s subsurface and surface environments."
Life in deep Earth totals 15 to 23 billion tons of carbon -- hundreds of times more than humans "Deep Carbon Observatory collaborators, exploring the 'Galapagos of the deep,' add to what's known, unknown, and unknowable about Earth's most pristine ecosystem"
Living in the Deep, Dark, Slow Lane (original news release) "Insights from the First Global Appraisal of Life Below the Earth's Surface"
Fig. 2. Microbial diversity in marine and terrestrial biome.
A team of geomicrobiologists walking to a sampling site at the end of an inactive tunnel in a South African gold mine. At this site almost 3 km deep beneath the surface, the researchers can access one of the deepest and oldest ecosystems on Earth. The brines in which these microbes live have been trapped in the rock for more than 1 billion years.
Bacteria from a Coal Bed 2 Km below the Pacific Ocean Floor off Japan
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