In nutrient-depleted coral reefs, some sponge species are thought to make carbon biologically available by excreting a form of “sponge poop” that other organisms feed on, thereby fueling productivity throughout the ecosystem. A diverse sponge population can affect water quality on the reef as the sponges filter water, collect bacteria, and process carbon, nitrogen, and phosphorus. Regardless of these differences, sponges are important inhabitants of coral reef ecosystems. While most sponges are found in the ocean, numerous species are also found in fresh water and estuaries. All corals require saltwater to survive.Sponges are very simple creatures with no tissues. Corals are complex, many-celled organisms.While sponges, like corals, are immobile aquatic invertebrates, they are otherwise completely different organisms with distinct anatomy, feeding methods, and reproductive processes. The approximately 8,550 living sponge species are scientifically classified in the phylum Porifera, which is comprised of four distinct classes: the Demospongiae (the most diverse, containing 90 percent of all living sponges), Hexactinellida (the rare glass sponges), Calcarea (calcareous sponges), and Homoscleromorpha (the rarest and simplest class, only recently recognized, with approximately 117 species).

Sponges have been around for a very long time, with certain species having a fossil record that dates back approximately 600 million years to the earliest (Precambrian) period of Earth’s history. Scientists believe that their varied colorations may protect them from the sun’s harmful ultraviolet rays. Sponges are found in a wide variety of colors, shapes, and sizes and are often mistaken for plants.

Do sponges move?