Some sponges can grow centimeters in weeks, and may have shorter life spans. These collar cells line the walls of small chambers throughout the water vascular system. These extra nutrients greatly augments sponge growth rate and competitive ability in coral reef systems. Sponges have been around for a long time. Sponges don't appear to do much at all, but in fact they are very active.
Sponges sit on the bottom of the sea actively pumping seawater through their bodies.
This water, containing nutrients, is filtered through a series of sieve-like pores. Sponges feed on these chemicals, modify and reuse them for their own purposes. Sponges do not have arms or legs and so they cannot physically remove other animals and plants settling on their exterior surfaces and from within water canals. Sponges are often full of small animals and microbes, particularly embedded within body cavities and throughout the water canals. Other sponges grow on top of corals, smothering and eventually eroding the dead coral, and some that bore into oysters and pearl oyster shells killing the animal inside.