Sea Urchins : Mass Death
The Red Sea’s spectacular coral reefs face a new threat, marine biologists warn—the mass death of sea urchins that may be caused by a mystery disease.
- Sea urchins belong to a group of marine invertebrates called echinoderms, which means spiny-skinned animals.
- It includes other well-known marine creatures like starfish and sea cucumbers.
- Sea urchins are characterized by their spherical to somewhat flattened, spiny bodies, and they are found in oceans worldwide, from shallow coastal waters to deep-sea environments.
- They live on the ocean floor, usually on hard surfaces, and use tube feet or spines to move about.
- The largest urchin (known from a single specimen) is Sperostoma giganteumof deep waters off Japan.
- They have a globular body and a radial arrangement of organs, shown by five bands of pores running from mouth to anus over the test (internal skeleton).
- The pores accommodate tube feet, which are slender, extensible, and often sucker-tipped.
- They have a hard exoskeleton, or test, made up of interlocking plates or ossicles, which are often covered with movable spines.
- From nodules on the test arise long, movable spines and pedicellariae (pincerlike organs); these structures may have poison glands.
