New Delhi: Today our world is visually dominated by animals and plants, but this world would not have been possible without fungi, say University of Leeds scientists in Britain.

Plants serve as the base of most of the food chains on Earth and along with animals; they dominate almost every ecosystem on the planet. But new analysis suggests fungi were equally vital on early Earth.

The recent UK-based study has found that fungi were essential in the creation of an oxygen-rich atmosphere, without which life on Earth wouldn't be possible. 

Researchers have carried out experiments where plants and fungi are grown in atmospheres resembling the ancient Earth and, by incorporating their results into computer models, have shown that fungi were essential in the creation of an oxygen-rich atmosphere.

Humans and other mammals require high levels of oxygen to function, and simulations in ancient Earth-like environment showed that fungi was important in establishing breathable atmosphere over 500 million years ago by ‘mining’ the nutrient phosphorus from rocks and transferring it to plants to power photosynthesis.

The research team: Dr Katie Field from the Centre for Plant Sciences, Dr Sarah Batterman from the School of Geography and Dr Benjamin Mills from the School of Earth and Environment, show that, “the planet developed an oxygen-rich atmosphere around 500 to 400 million years ago, as carbon dioxide was gradually photosynthesised by the first land plants.”

Why Fungi Is So Important?
Though plants performed the photosynthesis that harvested the sun's energy and converted carbon dioxide into oxygen, fungi provided the nutrients that allowed plants to thrive.

Today, plants can draw nutrients directly from the soil. But the roots of the earliest plants were less able and the soil they encountered was devoid of organic material. Thus, fungi were essential.

Fungi perform a function called ‘biological weathering.’ They produce organic acids that break down the rocks and mineral grains they grow on. On early Earth, this process freed up essential nutrients that could be accessed by plants. The plants, in turn, provided fungi with carbon.

The Lab Experiment:
The 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 richer in carbon dioxide to becoming similar to the air we breathe today.

One of the researcher from the team said that, “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.”

The full paper Nutrient acquisition by symbiotic fungi governs Palaeozoic climate transition is published in the Royal Society’s Philosophical Transactions B journal.

The research team is funded by the Natural Environment Research Council and the Biotechnology and Biological Sciences Research Council.

References:
http://www.leeds.ac.uk
https://www.inshorts.com
https://www.upi.com
https://www.ictorganics.com