Decomposition: Definition, Organisms involved, Process in Humans and its Significance

Decomposition: What happens to all the plants after they are dead? There occurs the process of decomposition after the plant dies. What do you mean by decomposition? And who is responsible for it? Are all the organisms involved in this process visible to naked eyes? What are the different processes involved in it?  What is its significance? What factors are needed for proper and fast decomposition?

We know that microbes help us in digesting our food but do you know that they can also digest us after death? If we want to know about decomposition, we have to include the microbes. We think death is the end of life, but at the same time, it is the beginning of another life! Another life here refers to the life of microbes. How does a dead matter transform into being part of the earth again? To know these all, read the full article.

Decomposition- Definition

Decomposition is the process of breakdown of complex organic matter into inorganic substances like carbon dioxide, water and nutrients.

Who is Responsible for Decomposition?

Organisms that are responsible for the decomposition process are called decomposers. Most of the decomposers are microorganisms that cannot be seen through naked eyes, like bacteria, some fungi, etc., but some decomposers are big enough that can be seen through naked eyes. Those are earthworms, beetles, millipedes, etc., called detritivores. Detritivores eat the dead organisms.

Some decomposers are:

1. Fungi– These produce enzymes that break down and digest dead, the decaying matter, which is then absorbed.
2. Bacteria– These help in the release of important nutrients like nitrogen and carbon back into the ecosystem.
3. Worms– Worms are decomposers. Like, earthworms help in decomposing organic material and make nutrients like phosphate readily available.
4. Insects– Insects like ants, dung beetles, flies, maggots, etc., are decomposers that help in decomposing dead organisms.

Steps of Decomposition

1. Fragmentation– The breakdown of dead or waste matter (like dead leaves) into its smaller particles is called detritus, and the process is called fragmentation.
2. Catabolism– It is characterised by the activity of bacterial and fungal enzymes by which detritus which is an organic material, gets degraded into simpler inorganic substances.
3. Leaching– There are some soluble and insoluble materials present in the detritus. Water-soluble inorganic nutrients seep or percolate deep inside the soil and get precipitated, and become unavailable salts. This is leaching.
4. Humification– Formation and accumulation of humus are called humification. Humus is a dark colloidal substance. Further decomposition of humus takes a lot of time as it is highly resistant to microorganisms.
5. Mineralisation– Humus gets further degraded, and inorganic material is released. This process is called mineralisation. This degradation is done by microbes. The process of mineralisation in humus takes place at a very slow rate, and the release of minerals is very slow, which is good for the soil and plants as more minerals at a time may percolate as unavailable salts. So, we say that humus-rich soil is good soil. Both humification and mineralisation occur inside the soil.

Factors Affecting Decomposition

1. Chemical composition of detritus- If detritus is lignin-rich, decomposition would be slow, but if it is sugar or nitrogen rich, decomposition would be faster.
2. Temperature- Enzymes work at optimum temperature. So if the temperature is optimum, then the rate of decomposition would be faster.
3. Moisture- Enzymes that act are hydrolytic in nature, so if sufficient moisture is there, then the rate of decomposition would be high.
4. Oxygen- As decomposition is an aerobic process, the rate of decomposition would be high if oxygen is present in the environment.

Stages of Decomposition in Humans

Decomposition of the body after death takes place in the following stages:-

1. Fresh– This is the first stage of decomposition when a person has just died. The condition of the body does not look much different. But this is the stage when decomposition starts. The heart stops beating as soon as a person dies. This halts the flow of the blood to each part of the body cells die by the autolysis process. The body gets stiffened after 4 to 6 hrs. of death, called rigor mortis.
2. Bloat– The immune system shuts down, and suddenly all the microorganisms get increased in this immune-environment. This increase in the number of microbes in the body is called putrefaction. These microbes begin to grow and start creating smelly gases like methane, hydrogen sulphide methane, etc. Due to these gases, there occurs extreme bloating of the body. These gases will push up the skin and cause ruptures in the body.
3. Active decay– Once rupture happens, processes start to speed up. Microbes from the environment cause active decay of the body.
4. Advanced decay– It is characterised by a decrease in the decay process as the dead material gets decreased.
5. Dry remains– This is the time when the body is becoming a skeleton. There are remains of bones during this stage like that of cartilage, skin, bone, etc.

Fig: Stages of Decomposition in Humans

Significance of Decomposition

Decomposition is an important process for the ecosystem. Without this process, our ecosystem would be deprived of nutrients. Like if a plant or an animal dies, decomposition starts, helps in returning the water, carbon dioxide and nutrients to the soil. If there is no decomposition, then nutrients that have been taken by plants and animals from the soil or other sources of the environment would get locked in them and then there would be no way to return them to the ecosystem.

Summary

From the above discussion, we came to know that decomposition is the process by which decomposers convert complex organic matter to the simplest inorganic substances. Several microorganisms like fungi, bacteria, etc. and detritivores like insects are responsible for the decomposition process. This process helps in returning nutrients back to the soil.

Decomposition of waste material like dead leaves involves fragmentation, humification, and mineralisation processes. All these processes involve catabolic reactions, and minerals are released and returned to the soil. Overload of nutrients in the soil causes leaching of nutrients which is not good for the soil and plants as minerals get precipitated. Decomposition of the human body involves different stages. These are fresh, bloat, active decay, advanced decay and dry remains.

Frequently Asked Questions (FAQs) on Decomposition

Q.1. What is the decomposition process?
Ans: Decomposition is the process of breakdown of complex organic matter into inorganic substances like carbon dioxide, water and nutrients are called decomposition.

Q.2. What are the important steps in decomposition?
Ans: 5 stages of decomposition are:-
a. Fragmentation
b. Humification
c. Mineralisation
d. Leaching
e. Catabolism

Q.3. Is decomposition good or bad?
Ans: Decomposition is good as it helps in returning the nutrients back to the ecosystem.

Q.4. What is humification?
Ans: The formation of humus from dead organic matter is called humification.

Q.5. What are the 4 factors that affect decomposition?
Ans: 4 factors that affect decomposition:
a. Chemical composition of detritus
b. Temperature
c. Moisture
d. Oxygen.

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