Microbes Likely Abundant Hundreds of Meters Below Sea Floor 68
sciencehabit writes "Samples drilled from 3.5-million-year-old seafloor rocks have yielded the strongest evidence yet that a variety of microorganisms live deeply buried within the ocean's crust. These microbes make their living by consuming methane and sulfate compounds dissolved in the mineral-rich waters flowing through the immense networks of fractures in the crust. The new find confirms that the ancient lavas formed at midocean ridges and found throughout deep ocean basins are by volume the largest ecosystem on Earth, scientists say."
Re:First life form (Score:5, Interesting)
Not even close. They may possess some similarities to the first cellular life forms which were almost certainly also chemovores (though likely lived in amino-acid rich muck on the bottom of shallow seas), but these organisms have been evolving for four billion years since then - they are every bit as evolved as humans, arguably far more so since their generations are so much shorter. They simply spent more time optimizing for a particular ecosystem niche whereas our ancestors kept changing directions dramatically. I mean come on - living in giant clonal colonies of billions of specialized individuals? Clearly a fad. It'll last a few billion years more, tops.
Re:Europa (Score:5, Interesting)
Indeed. In fact sunlight was probably largely irrelevant to Earth life for most of the first billion or so years it existed. Prevailing opinion is now that chemical energy from hydrothermal vents was probably the primary "food" early on, then eventually perhaps each other. Which makes sense if you think about it - complex chemistry would probably find chemical energy far more accessible than capturing radiation. Photosynthesis doesn't appear to have really caught on until much later, with the evolution of chlorophyll likely causing the first mass extinction event as it flooded the seas and atmosphere with toxic oxygen.
Of course Europa is a much smaller petri dish than Earth, and less energetic, so I'd suspect life would evolve much more slowly. If we do find life there, and it's anything like us (DNA, etc), it might provide a fascinating glimpse into what primitive life on Earth may have be like. Everything here on Earth is the product of around 4 billion years of evolution.