Soft-bottom Marine Benthos

Abstract

The term benthos applies to the organisms that inhabit ocean bottoms. Benthos distribution is controlled by a combination of factors such as sediment granulometry, dissolved O2, OM content, as well as disturbance and pollution. Functional classifications of soft-bottom marine benthos may follow different criteria, namely, size (micro-, meio- and macrobenthos); habitat preference (epifauna, infauna); feeding strategies (shredders, grazers, suspension- and deposit feeders); type of carnivory (predators and scavengers); or their contribution to sediment stability and/or erodibility (stabilizers and bioturbators). Deep-sea benthic ecosystems harbor a high biological diversity and several hypotheses have been invoked to explain such diversity and distribution patterns. Deep-sea ecosystems may be divided into two major groups, heterotrophic and chemosynthetic habitats, in relation to the energy fuelling them. Soft-bottom ecosystems play a major role in nutrient regeneration, through the processing of OM coming from different sources. The pelagic and benthic sub-systems are interconnected through physical or biologically-mediated processes, collectively known as benthic-pelagic coupling (BPC). Suspension-feeding, an example of biological BPC, is an energy-acquisition strategy convergently evolved among many phyla of marine organisms, that targets a profit from the large amount of particles suspended in seawater. There is no analogous mechanism to suspension-feeding in terrestrial ecology.