Infauna

A sediment-dwelling organism is a creature or micro-organism which lives mainly inside sediment – the layer of small particles at the bottom of a body of water. These are collectively known as infauna, as opposed to epifauna – the benthic organisms which live on the surface of the sediment.

Such creatures are found in the fossil record and include lingulata, trilobites and worms. They made burrows in the sediment as protection and may also have fed upon detritus or the mat of microbes which tended to grow on the surface of the sediment. Today, a variety of organisms live in and disturb the sediment. The deepest burrowers are the ghost shrimps – Thalassinidea – which go as deep as 3 metres into the sediment at the bottom of the ocean.

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