Which one of the following steps is not involved in the decomposition of detritus?
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → Sedimentation
Decomposition is the breakdown of detritus (dead leaves, bark, flowers, dead animals and faecal matter) into simple inorganic substances. Its steps are fragmentation, leaching, catabolism, humification and mineralisation.
(1) Catabolism — A step of decomposition. Enzymes of bacteria and fungi break detritus into simpler inorganic substances.
(2) Sedimentation — Not a step of decomposition. Sedimentation is the settling of particles at the bottom of water. It is used, for example, in sewage treatment, but it plays no part in breaking down detritus.
(3) Humification — A step of decomposition. It forms humus, a dark, amorphous substance that resists microbial action and decomposes very slowly.
(4) Fragmentation — A step of decomposition. Detritivores such as earthworms break detritus into small particles.
NCERT Extract:
Decomposition – “… The important steps in the process of decomposition are fragmentation, leaching, catabolism, humification and mineralisation. Detritivores (e.g., earthworm) break down detritus into smaller particles. This process is called fragmentation.”
Microbes in Sewage Treatment – “… Primary treatment : These treatment steps basically involve physical removal of particles – large and small – from the sewage through filtration and sedimentation.”