Earth

Soil

Soil formation

The action of the organisms

Organisms can contribute to the disintegration of the parent rock: plant roots enter the rock cracks and can produce acid substances that facilitate disintegration some sea molluscs produce acid substances that dig holes in the rock and use them as a shelter lichens manage to penetrate into the rock granules with their microscopic layers some bacteria produce carbon dioxide, ammonia, nitric acid, sulphurous acid. All these substances react with minerals and favour their alteration dead organisms are subject to decay, a process that produces substances like humic acids, carbon dioxide and ammonia. Those organisms that move in the soil can contribute to further crumble soil particles. Those organisms can be worms and coleopters, which transport bits of plants and animals from the surface to the lower layers.