A paper in Nature reports the discovery of fossil microbes possibly older, even much older, than any found previously. The lead author is biogeochemist Matthew Dodd, a PhD student at University College London. If the paper is right, these Canadian fossils could be 3.77 billion years old, or even as old as — hold onto your hat, in case you’re wearing one — 4.28 billion years.
From the Abstract:
Although it is not known when or where life on Earth began, some of the earliest habitable environments may have been submarine-hydrothermal vents. Here we describe putative fossilized microorganisms that are at least 3,770 million and possibly 4,280 million years old in ferruginous sedimentary rocks, interpreted as seafloor-hydrothermal vent-related precipitates, from the Nuvvuagittuq belt in Quebec, Canada. These structures occur as micrometre-scale haematite tubes and filaments with morphologies and mineral assemblages similar to those of filamentous microorganisms from modern hydrothermal vent precipitates and analogous microfossils in younger rocks. The Nuvvuagittuq rocks contain isotopically light carbon in carbonate and carbonaceous material, which occurs as graphitic inclusions in diagenetic carbonate rosettes, apatite blades intergrown among carbonate rosettes and magnetite–haematite granules, and is associated with carbonate in direct contact with the putative microfossils.
This new paper is interesting to compare with a paper from last year, Nutman et al., “Rapid emergence of life shown by discovery of 3,700-million-year-old microbial structures,” also in Nature, which found microbial structures that are a bit younger.
But the “microbial structures” from Nutman et al. 2016 are different from these new “microfossils” presented by Dodd et al. 2017. In Nutman et al., they only found stromatolite-type structures rather than actual microfossils. Some stromatolite experts were a bit skeptical that what they found were really stromatolites.
But the new paper by Dodd and his colleagues, “Evidence for early life in Earth’s oldest hydrothermal vent precipitates,” seems to offer potential bacteria-like microfossils. They are tiny black carbonaceous spheres and “hematite tubes” which the authors think are biogenically created. We’ve seen more convincing ancient microfossils, but these aren’t bad.
According to Dodd et al., these new finds would be the oldest known microfossils, if that is in fact what they are. Very interesting. If so, that just keeps pushing unquestionable evidence of life’s existence on Earth further and further back, which leaves less and less time for the origin of life to have occurred by unguided chemical evolution after Earth became habitable.
If they are in fact 4.28 billion years old, then that would mean there was life very, very early in Earth’s history — as Cyril Ponnamperuma said, it’s like “instant life.”
In zeroing in on this point, the Washington Post quotes Dodd:
If their results are confirmed, they will boost a belief that organisms arose very early in the history of Earth — and may find it just as easy to evolve on worlds beyond our own.
“The process to kick-start life may not need a significant length of time or special chemistry, but could actually be a relatively simple process to get started,” said Matthew Dodd, a biogeochemist at University College London and the lead author of the paper. “It has big implications for whether life is abundant or not in the universe.”
A “relatively simple process”? He’s right about the discovery having “big implications,” but maybe not in the way he intends.
It seems there are three observations to make: 1) The more we know, the more it seems that life arose rapidly on the early Earth, even more quickly that we previously realized. 2) How even the simplest life could arise, given materialist presuppositions, remains a profound mystery. This is the subject of Stephen Meyer’s book Signature in the Cell. 3) If life arises so easily, as Coyne’s friend Dr. Dodd suggests, then it’s strange we’ve seen no signs of it, at least not in an intelligent form, across the cosmos.
Taken together, these call into question materialist presuppositions, in the light of which 1, 2, and 3 present a tangle of contradictions. On the other hand, as a source of purposeful agency able to bring life into existence 1) quickly, 2) despite obstacles in the path of purely material processes, 3) uniquely, as it appears for now, on one planet, intelligent design fits the bill.
Photo: Hematite tubes, by Matthew Dodd via University College London.