Sea Sponges in the Caribbean

Sponge Taxonomy

• Sponges, despite lacking complexity, are classified as animals. Animals are multicellular organisms that do not have a cell walls, are heterotrophs, meaning they consume organic food, have a nervous system, and are diploid, which means that male and female reproductive gametes are different. In animals, gametes are sperm and eggs in males and females respectively. Sponges belong to the Calcarea, Hexactinellida, Sclerospongiae, and Demospongiae Classes. All four are unusual when compared to other animals because they are the only classes with members that display asymmetric symmetry. This means their bodies have no pattern of symmetry.

Sponge Characteristics

• Despite having cells, sponges do not have tissue with skin. Instead, sponges have two main cell layers that are separated by a gelatinous layer called the mesophyl. Despite not having tissue, sponges do have skeletal material. Spicules are essentially needles comprised of calcium carbonate or silica that are mainly responsible for support and protection of the sponge. Another type of structure known as a spongin is a protein structure that provides flexibility and support as well.

Sponge Lifestyle

• During its lifetime in the Caribbean Sea a sponge is completely sessile, meaning it does not move. Instead of chasing its prey, like most animals, sponges use a process known as filter feeding. A Caribbean sponge filters nearby water and consumes the small organic matter that inhabits it. Some sponges filter out and consume organic matter as large as shrimp. Once filtered food is sent to special cells known as amoeboids, which digest them.

Caribbean Sponge

• There are many different types of sponges that inhabit the Caribbean Sea. One, known as Aplysina cauliformis, exists in Antigua. It is long and thin and often comes in tints of purple and red. Another sponge classified as Callyspongia plicifera inhabits the Bahamas area and can be anywhere between 6 and 18 inches long. Clathrina canariensis is a yellow sponge that lives in the Saint Thomas area. It usually lives in shady areas like underwater caves.