Paleontologists Find ‘Bubbles of Oxygen’ in 1.6-Billion-Year-Old Stromatolites

Thursday, March 8, 2018

Fossilized bubbles and cyanobacterial fabric from 1.6 billion-year-old phosphatized microbial mats of the Chitrakoot Formation in central India. Image credit: Stefan Bengtson.

An international research team led by Swedish Museum of Natural History scientists has found that stromatolites (solid, laminar structures of biological origin) from the 1.6-billion-year-old Chitrakoot Formation in India contain abundant fossilized oxygen bubbles.

“Microbes were the first life forms on Earth,” said lead author Dr. Therese Sallstedt, from the Department of Paleobiology at the Swedish Museum of Natural History, and colleagues.

“They turned our planet into a tolerable environment for plants and animals and thus their activity paved the way for life as we know it today.”

“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.”

Dr. Sallstedt’s team studied fossilized sediments from central India and found round spheres in the microbial mats.

Fossilized bubbles and cyanobacterial fabric from 1.6 billion-year-old phosphatized microbial mats of the Chitrakoot Formation. Image credit: Stefan Bengtson.

Dr. Sallstedt’s team studied fossilized sediments from central India and found round spheres in the microbial mats.

These ‘bubbles’ were created by tiny microbes in what was once a shallow sea somewhere on the young Earth, according to the researchers.

“We interpret them as oxygen bubbles created in cyanobacterial biomats in shallow waters 1.6 billion years ago,” Dr. Sallstedt said.

SEM micrograph of the fossilized bubbles. Image credit: Stefan Bengtson.

“Cyanobacteria changed the face of the Earth irreversibly since they were responsible for oxygenating the atmosphere. Simultaneously they constructed stromatolites, which still exist on Earth today,” the paleontologists said.

“We 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.”

The team’s findings were published in the March 2018 issue of the journal Geobiology.

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T. Sallstedt et al. 2018. Evidence of oxygenic phototrophy in ancient phosphatic stromatolites from the Paleoproterozoic Vindhyan and Aravalli Supergroups, India. Geobiology 16 (2): 139-159; doi: 10.1111/gbi.12274

Source: www.sci-news.com

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