Breathable atmosphere down to fungi
12 Jan 2018 by Evoluted New Media
A team from Leeds University have shown that fungi were essential in the creation of an oxygen-rich atmosphere.
The researchers created atmospheres resembling the ancient Earth and used computer models to shown that fungi played a critical part in establishing the breathable atmosphere on Earth by ‘mining’ the nutrient phosphorus from rocks and transferring it to plants to power photosynthesis.
Dr Benjamin Mills from the School of Earth and Environment said: “Photosynthesis by land plants is ultimately responsible for about half of the oxygen generation on Earth, and requires phosphorus, but we currently have a poor understanding of how the global supply of this nutrient to plants works.
“The results of including data on fungal interactions present a significant advance in our understanding of the Earth’s early development. Our work clearly shows the importance of fungi in the creation of an oxygenated atmosphere.”
While many modern plants can gather their nutrients direct from soils through their roots, the earliest forms of plant life faced an entirely different climate, did not have roots and were non-vascular, meaning they could not hold water or move it around their system. The ‘soil’ they came into contact with was a mineral product lacking in organic matter, which is why their relationships with fungi were so important.
Fungi have the ability to extract minerals from the rocks they grow on through a process known as ‘biological weathering’. The fungi express organic acids which help to dissolve the rocks and mineral grains they grow across. By extracting these minerals and passing them on to plants to aid the plants’ growth, the fungi in return received the carbon which the plants produced as they photosynthesized carbon dioxide from the atmosphere.
Lab experiments undertaken by the Leeds team have shown that different ancient fungi, which still exist today, conducted these exchanges at different rates, which influenced the varied speeds at which plants produced oxygen. In turn this affected the speed at which the atmosphere changed from being much more rich in carbon dioxide to becoming similar to the air we breathe today.
The paper will be published in the Royal Society’s Philosophical Transactions journal.
