Marine benthic faunal successional stages and related sedimentary activity

This paper is a brief review of successional stages and activity of benthic . soft-bottom communities. Benthic communities was first described by Peter sen in the 1910s and further developed by Molander, Thorson and Margalef. S uccessional stages of benthic communities chance in a predictable way in re lation to environmental disturbance and food availability. Food supply to t he bottom can occur as a vertical flux, but transport through lateral advec tion is more important in some areas. While at the bottom, the infauna proc esses the food in many different ways, and the feeding modes can be categor ised into more than 20 functional groups, but fewer are present in brackish water. This categorisation is based on animal mobility and where and how t hey ingest the food. Animal activity in the sediment, bioturbation, has a s ignificant effect on redox conditions and diagenetic processes. Structures in the sediment due to infaunal presence and activity can be observed in si tu by sediment profile imaging, and the biogenic structures and redox condi tions can be parameterised and have been shown to correlate to benthic comm unity successional stages. The largest threat to benthic faunal biodiversit y is the spread of near-bottom oxygen deficiency in many enclosed are strat ified coastal areas.