Biological Weathering

A process which causes weakening and disintegration of rocks through the actions of plants, micro-organisms and animals. Biological weathering may be the start of a process but the actual weathering which occurs is physical or chemical weathering.

Plant roots grow into small cracks within rocks and soil aggregates, expanding the crack as they grow, and this forces them apart. Animals can also burrow and scrape away in soils and weakened rocks, leading to more rapid breakdown of the material.

Plants also exude weak acids from their roots, which can gradually dissolve and weaken rocks, leading to them to be more easily worn down. Decaying plants and animals will contribute numerous elements to a rock or soil profile and these can create acidic products which gradually dissolve the material.