“The Earth has more oxygen in the atmosphere thanks to longer days”

The speed at which the Earth rotates on its axis may have played a significant role in the amount of oxygen in the atmosphere. This is the conclusion of German and American scientists based on research on microbes.

As the days on Earth grew longer, microbes such as blue-green algae began to produce more oxygen through photosynthesis due to the many hours of sunlight, the scientists write in their article. Geosciences of nature. As a result, the oxygen content of the atmosphere steadily increased, which was crucial for the development of life on Earth.

six hour days

Over the years, the Earth has slowed down on its axis, in part due to the gravitational pull between the Earth and the Moon. When the Earth formed about 4.5 billion years ago, a day passed after six hours. Over 2 billion years later, it was 21 hours, and about 700 million years ago, the Earth was spinning on its axis in the current 24 hours.

For the study, microbes from a sinkhole in Lake Huron, on the Canada-US border, were selected. Here, in cold, oxygen-poor water, microbes live in ocean-like conditions soon after the earth is created.

In the lab, the researchers exposed the algae to light. This showed that they produced more oxygen the longer they stayed in the light, after which the scientists used models to calculate what the effect of this might be on a global scale. They then concluded that longer days may have played a vital role in the development of life on Earth.

More time to produce oxygen

When the days were shorter, microbes were less likely to produce oxygen, in part because they were thwarted by other microbes. That changed as the days grew longer and they had more time to expel oxygen, the scientists write.

One of the leading researchers, geomicrobiologist Gregoy Dick of the University of Michigan, explains that why oxygen levels have skyrocketed at times in Earth’s history has long been a question mark.

It was already suspected that microbes played a crucial role. “But we don’t know what factors played a role in this and when,” he says. A press release of his university. “Our research shows that the length of a day can respond to these patterns and timing.”