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Tiny fossils nearly two billion years old provide the first evidence of the existence of photosynthesis on Earth. This discovery, described as “significant,” will allow us to better understand how the first ecosystems emerged and to understand them more broadly. learn more about how life originated on our planet.
Tiny fossils at the origin of a major discovery. During excavations at a site called McDernott in a desert in northern Australia, a team of scientists extracted fossil bacteria from rocks estimated to be between 1.73 and 1.78 billion years old. Researchers describe them as Navifusa majensis, a suspected type of cyanobacteria. This is the name given to microorganisms that, like plants, use the sun’s energy to produce oxygen, a mechanism called photosynthesis.
This research, the results of which were published this week in the journal Naturecould provide a better understanding of how the first terrestrial ecosystems emerged and, more broadly, how life arose on our planet. “Our study provides direct evidence for the presence of metabolically active cyanobacteria that perform oxygen-containing photosynthesis.”said Catherine Demoulin, a paleomicrobiologist at the University of Liège (Belgium) and lead author of the study, in a press release citing the discovery “higher”.
Images show microfossil specimens of Navifusa majensis, a suspected species of cyanobacteria. – DEMOULIN ET AL. / NATURE
In less scientific terms, this discovery provides scientists with valuable clues to more accurately date when photosynthesis occurred on Earth. By conducting microscopic analysis, his team was able to identify structures inside these microorganisms (see below) that are remarkably similar to the thylakoid membranes in the cells of modern photosynthetic organisms and contain the pigment chlorophyll, which helps produce the light necessary for photosynthesis absorb.
Without photosynthesis there would be no life on earth!
Until this discovery, the presence of thylakoids in cyanobacteria only went back 600 million years. These tiny fossils represent the oldest traces of oxygen production through photosynthesis to date. As a reminder, this process uses sunlight to convert water and carbon dioxide into glucose and oxygen. This biological mechanism underlies the survival of almost all living things: photosynthetic organisms not only form the basis of most food webs, but their metabolic processes also fill the atmosphere with the breathable oxygen we need most to survive.
Matthieu DELACHARLERY
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