Bioturbation : Changes Produced by Benthos in Sediment Environments

In coastal and estuarine areas, infauna is known to affect physical, chemical and bio-logical properties of sediment by 'bioturbation', namely its feeding, burrowing, tube building, defecation and ventilation activities. In this paper we briefly review studies of the effects of bioturbation on sediment properties in following aspects, 1) particle size distribution, 2) water content, 3) sediment stability (erodability, resuspension), 4) Eh profile, 5) transportation of solutes and particles, 6) microbial density and activity, 7) biogeochemical activity, and 8) interactions among benthic animals. It has become increasingly clear that physical parameters of sediment are strongly influenced by the lifestyles of resident organisms. Bioturbation has been implicated in both the stabilization and destabilization of sediments. Although biogeochemical activities in the sediments are stimulated by the bioturbation of benthic animals irrespective of their life styles, the mechanism of stimulation differs between construction of macrof aunal semipermanent burrows and mixing of sediment. We suggest the importance of lifestyle of infauna in understanding the effects of bioturbation.