- Fungi & Algae
- Annelids (earthworms)
- Insects and orthopods like ants, beetles
- Reptiles like lizards, snakes.
- Mammals like rodents
Organisms living in the soil in detail
Organisms live in the soil surface, sub-surfaces, and even in the depths of the earth at the highest temperature.
Bacteria: These are organisms said to be omnipresent. That is they are found in air, water and land. However, the soil has more bacteria and it is their natural habitat. As per an estimate, there is a ton of active bacteria in an acre of soil.
Soil provides them a required environment for growth, multiplication and protection from the harsh climate. These bacteria, in turn, help the soil in being more porous, humid and also fertile. They act as decomposers and consume carbon compounds. They breakdown soil pollutants and also pesticides in it. Further, they enhance soil water retention and also involved in disease suppression.
Other animals and plants benefit from the presence of bacteria in the soil. These are only one which lives even in deepest layers of the earth.
Examples of soil bacteria include rhizobium, azotobacter.
Protozoa: These are microbes that have cells similar to animal cells. Also, they are motile and lack a cell wall. They like bacteria are spread in the soil. Mostly ciliate and ameboid protozoa are present in the soil. Of the amoebas, naked ones dominate soil. These protozoa feed on bacteria and fungi. They digest the bacteria and release more amount of nitrogen than the carbon consumed.
Fungi: Fungi are multi-cellular animals which are found largely in soils. They are microscopic and grow as long threads called hyphae. Like bacteria, they are also scavengers and help in the decomposition of waste. They can be divided into three types like
a) decomposers b) mutualists c) Pathogens and parasites.
Except for the pathogens, the other two are beneficial for plants and other animals.
The fungi help in making soil humid, fertile and suitable for the growth of plants. They can even kill nematodes and insects which destroy plants and acts a biocontrol agent.
Algae: These are similar to fungi but are autotrophic in nature. Algae are mostly found in water bodies like ponds and marines but also on the soil.
Nematodes: These are parasitic animals that can be found in soil. They are long, slender and can live as parasites on other animals and plants. Nematodes are said to be the largest population of animals living in the world. They are of different types like bacteria feeders, fungal feeders, root feeders, etc. This means they eat bacteria, fungi and plant roots respectively.
Annelids: Earthworms are the best examples of this class living in the soil. They make burrows in the soil and live in it. They help the penetration of water deep into the soil and also enhance soil fertility.
Example of annelid for this sort is the earthworm (called a farmers friend). Earthworms decompose dead and decaying matter and release tons of casts per acre every year. Thus they help in the recycling of nutrients in the soil.
Mollusks: These are animals with a smooth body having a calcium shell over them. They are found in large numbers in calcium-rich soils.
Insects and orthopods: a Large number of insects, arthropods like spiders, centipedes, etc. live in the soil. Ants, beetles, and mites are also found in large numbers in the soil. They utilize soil to make burrows and hills to live in them.
They act as fungal feeders, herbivores and predators. They help to aerate the soil and also regulate the population of other soil organisms.
Amphibians: As the name indicates, they can reside in the water and also on the land and burrows. However, frogs and toads live in the soil for a considerable period. They even undergo a hibernation period in the soil layers for quite long.
Reptiles: Most reptiles tend to live on trees, but some of them also live in soil burrows. These include lizards and also a few types of snakes.
Mammals: Mammals like rodents live in soil holes for the sake of safety and dwelling. They search for food on the soil surface. But rest inside the burrows, give birth and nourish their babies inside the soil. Examples include rodents.