Context:
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.
Relevance:
GS III: Species in News
Dimensions of the Article:
- Sea Urchins: Fascinating Echinoderms of the Ocean
Sea Urchins: Fascinating Echinoderms of the Ocean
- Sea urchins are a group of marine invertebrates belonging to the echinoderms, a phylum known for its spiny-skinned animals.
- Echinoderms also include well-known marine creatures such as starfish and sea cucumbers.
Physical Characteristics and Habitat:
- Sea urchins are easily recognizable by their spherical to somewhat flattened bodies covered in spines.
- They inhabit oceans worldwide, ranging from shallow coastal waters to deep-sea environments.
- These creatures predominantly reside on the ocean floor, often clinging to hard surfaces, and employ tube feet or spines for locomotion.
- Among them, Sperostoma giganteum, found in the deep waters off Japan, holds the distinction of being the largest urchin, albeit known from a single specimen.
Distinctive Features:
- Sea urchins exhibit a distinctive radial arrangement of organs, with five bands of pores running from the mouth to the anus over their internal skeleton, known as the test.
- These pores house tube feet, which are slender, extendable appendages, sometimes equipped with suckers.
- Sea urchins possess a robust exoskeleton called the test, composed of interlocking plates or ossicles, often adorned with movable spines.
- Long, mobile spines and pedicellariae, pincer-like organs that may contain poison glands, emerge from nodules on the test.
Feeding Habits:
- Sea urchins are primarily herbivorous, with a diet centered on algae and plant material.
- They employ specialized mouthparts, referred to as Aristotle’s lantern, to scrape algae and other food sources from rocks or the seafloor.
- Their feeding behavior plays a crucial role in maintaining the balance of underwater ecosystems by controlling algae growth in marine environments.
-Source: The Hindu
