Equally well known are the tube sponges of the tropics, coming in nearly every color of the rainbow. While not all sponges are as colorful or as large as those found in the tropics, sponges are an ancient and efficient design which will probably continue to populate the world's oceans longer than people will populate the Earth. In this photograph, the pumping action of a sponge is illustrated. A non-toxic yellow dye has been squirted around the base of a purple tube sponge in the Caribbean. Shortly thereafter, the dye is pumped out through the osculum at the top of the sponge.
Some sponges grow quite large.
Other barrel sponges get even bigger than this. Our educational film Beneath the Caribbean has some very interesting information about sponges. All content on this page is copyright Oceanic Research Group. For educational use only.