Porifera Phylum
The Porifera phylum is only concerned with the sponge organism. Sponges have no distinct respiratory system because they are so primitive, but they do require oxygen to survive like any other organism. The small pores (also known as ostia) in the sponge allow the sponge to absorb oxygenated water to receive the oxygen it needs. Cells, which are called choanocyte cells filter the oxygen that the water contains and then is able to filter out the carbon dioxide with the use flagella that moves the water throughout the sponge.
Tube Sponge
The tube sponge like any other sponge takes in oxygenated water through their ostia and take in the oxygen and deliver it to the cells. Once the oxygen has been used, the tube sponge will release the carbon dioxide with the use of choanocyte cells.
Barrel Sponge
The barrel sponge breathes like the tube sponge. The barrel sponge will take in oxygenated water through its ostia. With the use of the choanocyte cells, the sponge can rid itself of the carbon dioxide that the water brought into the sponge.
Row Pore Rope Sponge
The Row Pore Rope Sponge breathes exactly the same as the tube sponge and the barrel sponge. The Row Pore Rope Sponge will take in oxygenated water through its ostia and take in all of the oxygen. It will then release carbon dioxide with the use of choanocyte cells.