Rock & Gem

Stretching the Bounds of Early Life on Earth


Archaea are single-celled critters that lack nuclei, have a methane-based metabolism and are considered one of the oldest life forms on Earth. Many archaea are considered extremophi­les that live in hot springs and salt lakes that are hostile to most other life forms, but they’ve also been found in other environmen­ts including the gut, mouth and skin of humans.

A group of scientists led by Barbara Cavalazzi (University of Bologna, Italy) writing in the journal Science Advances claims to have found microscopi­c filaments of archaea in rocks no less than 3.42 billion years old! That’s about one billion years after Earth itself formed and solidified as a respectabl­e planet. If confirmed as bona fide fossils, these would be the oldest archaea discovered to date.

The thread-like fossils come from South African rocks that formed near the extreme conditions of ancient hydrotherm­al vents. While claimed to be archaea fossils by Cavalazzi and her colleagues, others argue they might be just inorganic mineral substances mimicking cell-like structures and filaments.

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