Bioturbation

Bioturbation is the reworking of soils and sediments by animals or plants.

Its effects include changing the texture of sediments (diagenesis), bioirrigation, and displacement of microorganisms and non-living particles. Common bioturbators include annelids (ringed worms) such as oligochaetes and Spirobranchus giganteus, bivalves like mussels and clams, gastropods, holothurians, or any other infaunal or epifaunal organisms. Faunal activities, such as burrowing, ingestion and defecation of sediment grains, construction and maintenance of galleries, and infilling of abandoned dwellings, all displace sediment grains and mix the sediment matrix.

The process leads to an increase in sediment-water interface, which facilitates particle exchange between the sediment and water column. In coral reefs sea cucumbers are one of the important bioturbators, capable of reworking approximately 4600 kg(dry weight) of sediment 1000 m² per year.

In soil science, pedology, geomorphology, and archaeology, bioturbation is the physical rearrangement of the soil profile by soil life. Plants and animals exploit the solum for food and shelter and, in the process, disturb the fabric of the soil and the underlying parent material. Burrowing animals (including insects) and plant root-systems form passageways for air and water movement, changing soil morphology. A passageway constructed by an animal that becomes backfilled with soil is known as a . Invertebrates that burrow and mound soil tend to produce a biomantle topsoil (soil biomantle), and as such are primary agents of horizonation. Uprooted trees break up bedrock, transport soil downslope, increase the heterogeneity of soil respiration rates, and disrupt soil horizonation.

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