Marine biologists are warning of a new peril to the stunning coral reefs of the Red Sea—widespread sea urchin deaths possibly linked to an enigmatic disease. Sea urchins, spiny-skinned echinoderms, share the oceans with familiar creatures like starfish and sea cucumbers. Found worldwide, they inhabit various marine environments, using their tube feet or spines for mobility. Their distinctive features include spherical bodies, radial organ arrangement, and a hard exoskeleton adorned with movable spines. Sea urchins are herbivores, relying on specialized mouthparts called Aristotle’s lantern to graze on algae and plants. The sudden decline of these vital grazers poses a grave threat to Red Sea coral ecosystems.
Facts/Terms for UPSC Prelims
- Echinoderms: Echinoderms are a phylum of marine invertebrates characterized by radial symmetry and spiny skin. Sea urchins, starfish, and sea cucumbers are notable members of this group.
- Aristotle’s Lantern: Aristotle’s lantern is a complex mouth apparatus found in sea urchins, enabling them to scrape algae and other food sources from surfaces using specialized mouthparts.
- Radial Arrangement: In sea urchins, organs are arranged in a radial pattern, typically five bands of pores running from the mouth to the anus over the internal skeleton, known as the test.
- Exoskeleton: An exoskeleton is a rigid external structure that provides support and protection. Sea urchins have hard exoskeletons made up of interlocking plates or ossicles.
- Pedicellariae: Pedicellariae are pincer-like organs found on sea urchins’ exoskeletons, and they play a role in cleaning and defense, possibly equipped with poison glands.