Earth's Rotation Slowed Down For Oxygen To Increase And Life To Evolve, Says Study

Earth¡¯s rotation slowed down around 2.4 billion years ago which could have ignited the growth of oxygen on our planet and helped life thrive.

NASA

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This is according to a new study shared by University of Michigan researchers that explains that Earth¡¯s rotation period might have been around six hours when it was around four billion years old but it gradually slowed down to 24 hours that we¡¯ve been seeing today.

Looking back at 2.4 billion years ago, oxygen on Earth barely existed in the atmosphere, so no living organisms could live or even survive. Instead, microbes breathed carbon dioxide, and cyanobacteria produced oxygen -- one of the earliest forms of photosynthesis.

However, in around 400 million years, Earth¡¯s atmosphere went to one-tenth the amount of oxygen we have now. In case you didn't know, that¡¯s a massive leap. This explosion of oxygen allowed animals and plants to evolve and more plants started making oxygen along the way.

Researchers wanted to learn where the burst of oxygen originated and for this, they looked at the Middle Island Sinkhole in lake Huron. The waterbody has a layer of 400 million-year-old limestone, dolomite and gypsum bedrock that formed from the saltwater seas that once were everywhere across the continent.

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Also here is purple-oxygen producing cyanobacteria that use photosynthesis to produce oxygen. But with this, there are other white sulfur-oxidising bacteria that covers the cyanobacteria during the day and evening, blocking sunlight to reach it and preventing it from carrying out their photosynthesis.

When sunlight levels increase to a critical threshold, the bacteria move back down below the cyanobacteria and allows them to produce oxygen.

AP

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Judith Klatt of the Max Planck Institute for Marine Microbiology and lead author, explained, ¡°Two groups of microbes in the Middle Island Sinkhole mats compete for the uppermost position, with sulfur-oxidizing bacteria sometimes shading the photosynthetically active cyanobacteria. It's possible that a similar type of competition between microbes contributed to the delay in oxygen production on the early Earth.¡±

University of Michigan geomicrobiologist Gregory Dick added, ¡°The idea is that with a shorter day length and shorter window for high-light conditions in the afternoon, those white sulfur-eating bacteria would be on top of the photosynthetic bacteria for larger portions of the day, limiting oxygen production.¡±