An example of a decomposer is an earthworm. It slithers through the soil and it comes across a dead bug. It eats the dead bug's tissues. Enzymes in the worms system mixes with the tissues it has eaten. When the worm eliminates the changed tissues from its body, the soil gains new nutrients. Other types of decomposers are fungi and bacteria.
http://ecology5thperiod.wikispaces.com/Decomposers... is where i got the earthworm.
http://en.wikipedia.org/wiki/Decomposer#Fungi is where i got the fungi.
http://www.digitaljournal.com/science/pulsed-electrical-fields-destroy-antibiotic-resistant-bacteria/article/384834 is where i got the bacteria.