Origin of life after mere 400 million years of earth's formation!

Origin of life is one of the biggest mystery of our times. Various hypothesis have been proposed from time to time but origin of life near hydrothermal vents has emerged as one of the most plausible one. There are swathes of ecological systems discovered at the sea bed which are completely cut-off from the photosynthesis based life which we have extensive knowledge. Many elements and organic compounds have been detected in the plumes emanating from the hot core of the earth. The presence of oceans soon after the origin of earth have strengthened the idea that our early ancestors could have emerged here. 

Now a study done by Dodd et al. have discovered fossilized micro-organisms nearly 4.2 billion years old in sedimentary rocks in Quebec Canada. Before this discovery previous record for oldest confirmed fossils are not older than 3.5 billion years. This is a giant leap in terms of hardcore evidence which places us now back by nearly 700 million years. 

The key analogous structure which this study found share a similar morphology and mineral composition with existing hydrothermal vents organisms.Basically, Iron metabolizing ancient microbes left the traces e.g. formation of multiple tubes from a single hematite source at varying angles which would not have formed naturally without any biological input. Similarly, coiled, branched and twisted filament structures cannot be explained by any abiogenic pathway. Interestingly again, extant microbes still produce hematite tubes and filaments around hydrothermal vents. These filaments gets coated by silica and later Iron oxyhydroxide in successive venting. Similar knobs are also created by chemolithotroph Leptothrix-type bacteria. Other than that twisted morphology is formed by a proteobacteria called Mariprofundus.

Conditions near hydrothermal vents could have supported
primitive life. These types of vents might be present on
Europa or Ganymede.

These fossilized remains of ancient micro-organism shares stark resemblance with the organisms still living on this planet. The discovery not only fuels debate regarding origin of life but also extraterrestrial life. The fact that these ecological communities with its entire food web can survive even in the absence of sun is simply fascinating. At the time when terrestrial and oceanic life would dwindle in the absence of sun, these communities will continue to thrive as if sun never existed. The range of organisms from chemolithothrophic microbes to crabs, eels and fishes form similar food chain of predator and prey as other oceanic and terrestial organisms form. We can use this knowledge to detect life not only on our planet but other unknown worlds too. The moons like Ganymede or Europa might have underwater hydrothermal vents and who knows what type of ecological communities are lurking beneath these frozen wonder.

Reference:

Dodd, M. S., Papineau, D., Grenne, T., Slack, J. F., Rittner, M., Pirajno, F., ... & Little, C. T. (2017). Evidence for early life in Earth’s oldest hydrothermal vent precipitates. Nature, 543(7643), 60-64.