ENVIRONMENTAL SCIENCE : ECOSYSTEM 121
DECOMPOSERS
In this world all living organisms require a constant supply of nutrients for growth. The
death and decomposition of plants and animals, with release of nutrients constitutes an
essential link in the maintenance of nutrient cycles. When an organism dies, an initial
period of rapid leaching takes place and populations of macromolecules. The dead organism
is disintegrated beyond recognition. Enzymic action breaks down the disintegrating parts of
the litter. Animals invade and either eat the rapidly recolonized by micro- organisms, and
the litter biomass decreases. It becomes simpler in structure and chemical composition.
Process of Decomposition
The process of decomposition involves three interrelated components, viz.
(i) Leaching (ii) Catabolism, (iii) Comminution.- Leaching
Leaching is a physical phenomenon operating soon-after litter fall. Soluble matter is
removed from detritus by the action of water. Sometime over 20% of the total nitrogen
content of litter maybe leached off.
- Catabolism
The process in a plant or animal by which living tissue is changed into waste products.- Comminution
Comminution to make small to reduce to power or minute particles. Comminution
means the reduction in particle size of detritus. During the course of feeding, the decomposer
animals community detritus physically. And utilize the energy and nutrients for their own
growth (secondary production). In due course, the decomposers themselves die and contribute
to the detritus.
Function of Decomposition
The two major functions of decomposition within ecosystems are as under:-
(1) The mineralization of essential elements,
(2) The formation of soil organic matter to inorganic form.
The formation of soil organic matter in nature is a slow process. The decomposition of
any piece of plant detritus may take hundreds of years to complete. However, some residues
of decomposition within this period do contribute to the formation of soil organic matter.
Community of Decomposer Organisms
The community of decomposer organisms includes several bacteria, fungi, protests and
invertebrates. The different species in such a community function in an integrated manner.
For example, a fungus decomposes plant litter and is eaten by an animal. Upon death,
bacteria decompose the animal, and protozoa may eat the bacteria.
Fungi and bacteria are the principal organisms that break down organic matter. Certain
protozoa, nematodes, annelids and arthopods strongly influence their functioning (i.e. of
fungi and bacteria) due to their feeling activities. Microarthopod fauna, comprising mainly
of oribatid mites besides other mites and collembolans, are abundant in most forest, grassland
and desert ecosystem.