Monday, May 26, 2008

Ecosystem-Decomposition

Decomposers break down complex organic matter into inorganic substances like carbon dioxide, water and nutrients and the process is called decomposition.
Detritus
Dead plant parts such as leaves, bark, flowers, and dead remains of animals including fecal matter are called detritus.
ØAboveground detritus –litter fall
ØBelowground detritus-It is composed of dead roots (Root detritus).





Fragmentation
It is mainly due to the action of feeding invertebrates (Detritivores). They break down into smaller particles. Detritus gets pulverized when passing through the digestive tracts of animals. Due to fragmentation the surface area of detritus particles is greatly increased and it comes out in the form of warm casting.


Leaching
Water percolating through soil removed soluble substances (Sugars, several nutrients) from the fragmented detritus due to leaching
Catabolism
The extra cellular enzymes released by bacteria and fungi carry out catabolism.i.e. enzymatic conversion of the decomposing detritus to simpler compounds and inorganic substances. All the three processes of decomposition operate simultaneously.
Humification
Humification leads to accumulation of a dark amorphous substances called Humus. It is highly resistant to microbial action and undergoes decomposition at an extremely slow rate. a Colloid in nature it serves as a reservoir of nutrients. The humus is further degraded by some microbes and release of inorganic nutrients occur by the process known as mineralization.

Humus

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