Deep-sea Arctic Spongers

Deep-sea Arctic spongers have been known to eat fossils. These creatures live at depths of over 2,000 meters (6,600 feet) below the surface of the ocean. Scientists believe they may be able to use these sponges to help them understand how ancient marine ecosystems functioned.  Sponges are filter feeders. They collect food particles from the water using their bodies and then pass those particles through their pores. In order to do this, they need to build up layers of material around themselves. Over time, these layers become compacted together, forming hard structures called spicules. These spicules act as a protective barrier against predators and provide stability to the sponge.

 Fossil sponges were discovered off the coast of Norway in 2008. When scientists examined the sponges, they noticed that they had formed a layer of sediment around them. This was evidence that the sponges had been buried under the sea floor for millions of years.   The researchers believe that the sponges might be eating bacteria that lived inside the shells of dead animals. Bacteria would have been trapped inside the shells after the animals died. As the sponges ate the bacteria, they would have released carbon dioxide into the surrounding water. Carbon dioxide is what makes up the majority of Earth's atmosphere.  The sponges' diet could also have included algae and plankton. Algae and plankton are microscopic organisms that float near the surface of the ocean and are eaten by many different species.  There are two types of sponges that live in the deep sea. One type lives in the upper waters of the ocean and the other lives in deeper waters. Both types of sponges are filter feeder.   The sponges that live near the surface of the oceans are called bathyal sponges. Their habitats range from tropical to temperate regions.  The sponges in the deep sea are called abyssal sponges. They live in colder temperatures than the bathyal spongies.

 To date, scientists have only found one species of sponge that eats fossils. However, they believe that there are likely many more species out there that haven't yet been identified.  The sponges are not the first creatures to consume fossils. Many other animals have been known to eat fossilized remains.   A few examples of animals that eat fossils are crabs, worms, mollusks, snails, starfish, and octopuses.  Fossils can be found in rocks that are hundreds of thousands of years old.   Fossils are preserved remains of past life forms.   Fossils are often found in sedimentary rocks.