Metal particles and their role in the oxygenation of the Earth’s atmosphere –

Until now, scientists have argued that oxygen levels rise as a result of photosynthesis by algae and plants in the sea, where oxygen is produced as a by-product and released into the atmosphere.

But a research team from the University of Leeds says photosynthesis theory does not fully explain the rise in oxygen levels.

In an article published today (Monday, March 6) in the journal Natural Earth SciencesResearchers claim that when algae and plants died, they would have been eaten by microbes, a process that takes oxygen from the atmosphere.

As a result, the amount of oxygen in the atmosphere was a balance between what was produced by photosynthesis and what was lost as the decomposition of dead plants and algae.

To allow oxygen levels in the atmosphere to rise, scientists say the decomposition process must have slowed or stopped. This happened through what is known as mineral organic carbon conservation, in which ocean minerals, particularly iron particles, bind to dead algae and plants and prevent their decomposition and decomposition.

The overall result is that oxygen levels were able to rise unimpeded.

Caroline Peacock, professor of biochemistry at Leeds’ School of Earth and Environment, who led the research, said: “Scientists have known for many years that mineral particles can stick to algae and plants, making them less likely to be attacked by spores and protecting them from the decomposition process, but It has not been tested whether metal particles helped increase atmospheric oxygen.”

The researchers set out to test their theory against known geological events when levels of metallic particles were likely to have been higher, for example, when the continents formed, resulting in more land area from which minerals — including particles of iron — could erupt. or washed up in the oceans.

For example, the Great Oxidation Event 2.4 billion years ago saw a sharp rise in oxygen levels in the atmosphere. This coincided with the gradual formation of the continents, which would have caused more metallic particles to sink into the oceans.

The study was conducted by Dr Mingyu Zhao, previously working in Leeds but now at the Chinese Academy of Sciences in Beijing. He said: “Increased mineral particles in the oceans would have reduced the rate of algae decomposition. This had a significant impact on oxygen levels, allowing them to rise.”

The increase in atmospheric oxygen had major implications for the evolution of life. This led to the evolution of increasingly complex organisms, which moved from water to land.

For Professor Peacock, the study not only provides a better understanding of how Earth’s atmosphere is oxygenated, but also provides insight into the conditions needed for the development of complex life on other planets.

She said: “Our research provides a new understanding of how Earth’s atmosphere became highly oxygenated, which ultimately allowed the evolution of complex life forms.

“This gives us important insight into the conditions that must exist on other planets for intelligent life to thrive.

“Having water on a planet is only part of the story. There has to be dry land to provide a source for the mineral particles that will eventually end up in the oceans.”