They argue that, if that;s true, life should be common in the universe. From ScienceDaily:
Scientists want to know how long life has existed on Earth. If it has been around for almost as long as the planet, this suggests it is easy for life to originate and life should be common in the Universe. If it takes a long time to originate, this suggests there were very special conditions that had to occur.
Actually, that doesn’t quite follow. There could have been very special conditions at the beginning. And, absent very special conditions, maybe life just would not originate at all.
This new study reveals a primary biological control step in microbial sulfur metabolism, and clarifies which cellular states lead to which types of sulfur isotope fractionation. This allows scientists to link metabolism to isotopes: by knowing how metabolism changes stable isotope ratios, scientists can predict the isotopic signature organisms should leave behind. This study provides some of the first information regarding how robustly ancient life was metabolizing. Microbial sulfate metabolism is recorded in over a three billion years of sulfur isotope ratios that are in line with this study’s predictions, which suggest life was in fact thriving in the ancient oceans. Paper. (open access) – Min Sub Sim, Hideaki Ogata, Wolfgang Lubitz, Jess F. Adkins, Alex L. Sessions, Victoria J. Orphan, Shawn E. McGlynn. Role of APS reductase in biogeochemical sulfur isotope fractionation. Nature Communications, 2019; 10 (1) DOI: 10.1038/s41467-018-07878-4 More.
The question one is left with is, if life is 3.5 billion years old, why did it only become quite interesting about half a billion years ago (if that’s the story)? The microbes that metabolized practically anything just to stay alive didn’t appear to want to do much else. Yes, it’s an old question why they didn’t (couldn’t?) Or maybe they even did. But based on the history of the last half-billion years, there should be an answer.
See also: Photosynthesis Pushed Back Even Further. Time To Revisit The “Boring Billion” Claim
Earth’s “boring billion”now hot again (2015)
The “boring billion” years: New hypothesis suggests oxygen shortage stalled life (2014)
Why was there a “boring billion” years of single cell life? (2014)