Scientists have photographed 1.6 billion years old fossilized oxygen bubbles, which are believed to have been created by microbes in what was once a shallow sea somewhere on young Earth.
The microbes and these bubbles are of special interest as scientists say they are not only give us information about first forms of life, but they could also help us understand how our planet was turned into a place wherein further life could spawn, grow and evolve.
Some of these early microbes were cyanobacteria that thrived in early shallow waters. They produced oxygen by photosynthesis, and sometimes the oxygen got trapped as bubbles within sticky microbial mats.
Fossilized bubbles and cyanobacterial fabric from 1.6 billion-year-old phosphatized microbial mats from Vindhyan Supergroup, central India. Credit Stefan Bengtson.
The bubbles in the photos were preserved, and today they can be seen as a signature for life.
Ph.D. Therese Sallstedt and colleagues from University of Southern Denmark, Swedish Museum of Natural History and Stockholm University studied fossilized sediments from India, and they found round spheres in the microbial mats.
We interpret them as oxygen bubbles created in cyanobacterial biomats in shallow waters 1,6 billion years ago, said Therese Sallstedt.
Cyanobacteria changed the face of the Earth irreversibly since they were responsible for oxygenating the atmosphere. Simultaneously they constructed sedimentary structures called stromatolites, which still exist on Earth today.
The researchers now think that cyanobacteria played a larger role than previously believed in creating phosphorites in shallow waters, thereby allowing today’s scientists a unique window into ancient ecosystems. They published their findings in the journal Geobiology.