[Rockhounds] 1.75-Billion-Year-Old Fossils Are Oldest Record of Oxygenic Photosynthesis

[Kreigh Tomaszewski]

The story of life on Earth can’t be told without photosynthesis, the
process by which plants (and some other lifeforms) convert sunlight into
chemical energy. Now, a team of researchers has announced the discovery of
fossilized photosynthetic structures—the oldest yet known—from a staggering
1.75 billion years ago.

The structures belong to microfossils of *Navifusa majensis*, a presumed
cyanobacteria found in northern Australia. Cyanobacteria are a type of
microorganism that get energy from oxygenic photosynthesis, by which water
and carbon dioxide are converted—using energy from sunlight—into glucose
and oxygen. Thus, the ancient bacteria help scientists understand how one
of the most fundamental life processes on Earth arose. The team’s research
is published <https://www.nature.com/articles/s41586-023-06896-7> today in
Nature.

“This discovery extends the fossil record of such internal membranes by at
least 1.2 billion years,” said Emmanuelle Javaux, a biologist at the
University of Liège in Belgium and a co-author of the study, in an email to
Gizmodo. “The arrangement of these membranes in fossil cells allows their
unambiguous identification as cyanobacteria actively performing early
oxygenic photosynthesis at the time of death 1.75 billion years ago!”

In other words, the fossil is a remarkable window into a fundamental
process on Earth, one that gave rise to life as we know it. Australia is
rich ground for fossils of bacteria, which shed light on some of the
earliest life on Earth. Indeed, the oldest known evidence for life on Earth
comes in the form of nearly 3.5-billion-year-old stromatolites
<https://gizmodo.com/abigail-allwoods-hunt-for-alien-fossils-on-mars-has-beg-1846344495>,
layered concretions of ancient microbes.

https://gizmodo.com/1-75-billion-year-old-fossils-are-oldest-record-of-oxyg-1851137333