Longer Days Led to Oxygen Buildup on Early Earth: Study

Researchers propose that some of the planet’s earliest photosynthesizers benefited from a slowing of the Earth’s rotation that allowed them to produce a surplus of oxygen and paved the way for more complex life.

Written byAmanda Heidt

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A finger of purple bacteria sticks up from the bottom of a lakebed

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ABOVE: Purple microbial mats in the Middle Island sinkhole in Lake Huron. Small hills and “fingers” like this one in the mats are caused by gases like methane and hydrogen sulfide bubbling up beneath them.
PHIL HARTMEYER, NOAA THUNDER BAY, NATIONAL MARINE SANCTUARY

Billions of years ago, Earth lacked the oxygen-rich atmosphere that today sustains most life on the planet. How the air slowly became breathable remains an unanswered question, but in a study published yesterday (August 2) in Nature Geoscience, researchers are putting forth a novel hypothesis: that the gradually slowing rotation of the Earth, which led to longer days, allowed photosynthesizing cyanobacteria to pump more oxygen into the atmosphere than they had before.

“An enduring question in the Earth sciences has been how did Earth’s atmosphere get its oxygen, and what factors controlled when this oxygenation took place,” University of Michigan geomicrobiologist and study coauthor Gregory Dick says in ...

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A purple bulge of microbes on the bottom of a lake

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Meet the Author

Amanda Heidt
Amanda first began dabbling in scicom as a master’s student studying marine science at Moss Landing Marine Labs, where she edited the student blog and interned at a local NPR station. She enjoyed that process of demystifying science so much that after receiving her degree in 2019, she went straight into a second master’s program in science communication at the University of California, Santa Cruz. Formerly an intern at The Scientist, Amanda joined the team as a staff reporter and editor in 2021 and oversaw the publication’s internship program, assigned and edited the Foundations, Scientist to Watch, and Short Lit columns, and contributed original reporting across the publication. Amanda’s stories often focus on issues of equity and representation in academia, and she brings this same commitment to DEI to the Science Writers Association of the Rocky Mountains and to the board of the National Association of Science Writers, which she has served on since 2022. She is currently based in the outdoor playground that is Moab, Utah. Read more of her work at www.amandaheidt.com.
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