5.1.11—Soil in element recycling

Detritivores fragment litter; saprotrophs secrete enzymes and decompose it, releasing nutrients that plants can reuse.

Keep physical breakdown separate from chemical decomposition. The chain is litter → fragments → microbial breakdown → inorganic nutrients → plant uptake.

Earthworms shred leaves, fungi decompose the fragments, and nitrate released later enters plant roots.

Fungi and bacteria are saprotrophs that carry out extracellular chemical decomposition; detritivores such as earthworms mainly ingest and fragment litter.

Decomposition is not the same as eating litter; identify the chemical transformation step.