What helps to circulate water through sponge?

Sponges are not like fish,but I think that they have most of the same requirements as them.Sponges are living organisms so they need things for them to survive.Water is one of them,so if they are out of the water too long eventually they will dry out.I'm not sure what sponges eat or if they eat anything at all.Now that you mention it,I am going to have to look that up.If you have seen SpongeBob the movie,in one part of the movie this scubadiver puts SpongeBob under a bright light to dry him out,and he's a sponge.It doesn't sound scientific but it could be based on true science,but I doubt it.