ABSTRACT
Suspension-feeding is widely distributed among marine organisms among both plankton and benthos. Filter-feeding is often used as a synonym for suspension-feeding, suggesting that sieving is the trapping mechanism, but a wide array of methods for collecting particles from suspensions occurs. Bioturbation comprises all processes of sediment reworking by organisms. The main bioturbators are found among deposit-feeders that feed on organic particles in soft sediments. Like suspension-feeders, deposit-feeders have developed several ways to collect these particles. Funnel-feeders and conveyer-belt deposit-feeders produce a biogenic layering of the sediment. They feed at a certain depth below the sediment and ingest only those particles they can swallow; later these are deposited at the sediment surface. Traces left by organisms in intertidal sediments have been studied for a long time, but few biologists have studied these traces; most trace specialists are geologists. This emphasizes the special role of trace fossils in the fossil record: they represent fossil behavior.
