Sea Bottom : Round Worms (Nematoda)

Nematodes live in the oceans, in freshwater, in soils or they can be parasitic – they are simply everywhere. In the oceans, they occur in all environments, often in high numbers, from shallow coastal sediments to the deep-sea. Overall, more than 12,000 species of round worms are known, but scientists estimate that more species are undescribed than described. The number of Arctic species identified to date is 300-400.

Nematodes have a cylindrical tapered body shape adapted to live in the minute space between sediment grains or in other small spaces; many are smaller than 1 mm. They have a typical wriggly movement driven by longitudinal muscles, hydrostatic pressure and lack of circular muscles.

Feeding types vary between nematode species, many are carnivorous, others feed on plant material, yet others are deposit-feeders.