Food on the surface of grains
Deposit-feeding sea cucumbers gather sediment from the upper few centimetres of the seabed. Branching tentacles that evolved from tube feet pick up grains together with fragments of organisms, bacteria and microalgae. Other species extend their tentacles into the water to trap suspended food.
Digestion and absorption
Muscular contractions move the sediment from the oesophagus through the stomach and intestine to the cloaca. Enzymes break down proteins, carbohydrates and lipids into molecules the animal can assimilate. Ingested microorganisms can also provide nutrients. As most mineral grains pass through, digestion changes the organic matter and microbial communities they carry.
