Scientists are looking at how soil microbes affect the binding of carbon in the earth. For example, dirt, in which only bacteria live, emits more carbon dioxide when heated than inhabited by fungi.

Earth’s soils contain three times more carbon than the atmosphere. The reason is in microorganisms (bacteria and fungi), which turn decaying matter into carbon-rich soil. But not all carbon compounds are equally lucky: some are stored for decades or even centuries, while others are quickly absorbed by microbes and turn into carbon dioxide, which rapidly evaporates.

The study showed that in the laboratory, fungal-rich soils emit less carbon dioxide when heated. In other words, fungi are needed to create soil that “binds” the carbon in the earth.

Scientists have turned to such experiments because climate change threatens to release large amounts of carbon from the earth, which will worsen global warming. As it turned out, an increase in ambient temperature encourages soil microorganisms to multiply actively, and huge hungry colonies quickly eat up easily digestible carbon compounds. And then – they pounce on the old carbon reserves, turning the eaten into carbon dioxide.

Computer models based on three factors – rising temperatures, disappearing forests, intensive farming damaging soil microbial colonies – show that by 2100, the earth will store 40% less carbon than expected.

But understanding the logic of creatures living in mud is not an easy task. According to scientists, soil is the most difficult community on the planet. To make the first steps easier, researchers at the University of Zurich have grown mud in a laboratory. They separated fungi and bacteria from forest soil, and then distributed them in five Petri dishes: one with fungi, one with bacteria and three with mixtures of microorganisms. Everyone was fed sugar and left alone for four months to produce mud. And then the samples were heated and measured how much carbon dioxide would be released.

Bacteria turned out to be the best soil builder, but fungi-rich soil emitted less carbon dioxide when heated than bacteria-only soil. Perhaps the reason is that fungi produce enzymes – proteins that can both build and destroy other molecules. But bacteria by themselves do not know how to produce such compounds. It turns out almost symbiosis: fungi produce protein, and bacteria “build” new soil from them. This, in turn, leads to the formation of carbon compounds with a long shelf life.

Of course, not all laboratory experiments are reproduced in nature, but this is an important step towards understanding the complex relationships within the earth. And also to develop methods for storing carbon in the soil and protect the atmosphere from unnecessary emissions.