Most of the sea bed beyond shallow waters is covered by thick sediments of sand or mud. Very few large and conspicuous organism are found there. If we dig better into this, literally, a rich animal fauna can be found buried into the sediments. Many organisms live in this habitat are detritus feeders, basically eating the bottom sediments that are rich in organic material. This organic material can originate from river runoff or from dead pelagic animals or algae. Other Benthic Invertebrates, especially bivalves filter food from the ocean and in fact clean it up.

Animals that bury themselves into the sediments, especially polychaets increase the oxygen flow in the sediments and therefore make it more habitable for other animals (much the same as earthworms do on land). Benthic organism are therefore of great importance for the oceanic environment.

More life is found on mud bottoms than sand bottoms as there is more organic material available there as food. However, organisms can live deeper in the sand, where oxygen does reach deeper into the sediment. The richest life on soft bottom can be found on shell sand as different shaped shell fragments invite different adaptations.

HV