Sponges do not have the ability to pursue food. So, in the case of the star encrusting sponge, it is no different. the sponge has no fins or anything to mobilize it. Instead, it is made up of pores where water can pass through. The reason that the water must pass through the sponge is in order to collect food. Water has many particles of food and bacteria floating in it so whenever the sponge expands itself by beating it's flagella andwater gets sucked into the sponge. These tiny particled get trapped inside of the sponge and te nutriesnts are absorbed by a process known as phagocytocis. Phagocytocis is the indigestion of bacteria or other natural material by phagocytes and ameoboid protozoans. a photo of the process of phagocytosis is shown to the right. after the water is ventilated, it is pushed back into the rest od the water an the process is completed.