 Sponges are worldwide in their distribution, living in a wide range of ocean habitats, from the polar regions to the tropics.Most live in quiet, clear waters, because sediment stirred up by waves or currents would block their pores, making it difficult for them to feed and breathe.The greatest numbers of sponges are usually found on firm surfaces such as rocks, but some sponges can attach themselves to soft sediment by means of a root-like base.