Search results
Results from the WOW.Com Content Network
Sea urchins or urchins (/ ˈ ɜːr tʃ ɪ n z /) are typically spiny, globular animals, echinoderms in the class Echinoidea. About 950 species live on the seabed, inhabiting all oceans and depth zones from the intertidal to 5,000 metres (16,000 ft; 2,700 fathoms). [1]
Sea urchins are covered with plates which are usually fused together to give a rigid test, but in the order Echinothurioida, the test is leathery because the plates are separate. The test is divided into five segments that extend from the apex to the mouth.
Echinus is a genus of sea urchins.Sea urchins are echinoderms that are typically spherical or flattened with a covering of spine-like structures. Sea urchins tend to be important members of their ecosystems by grazing on other organisms and stabilizing populations.
In 1983, for example, the mass mortality of the tropical sea urchin Diadema antillarum in the Caribbean caused a change from a coral-dominated reef system to an alga-dominated one. [98] Sea urchins are among the main herbivores on reefs and there is usually a fine balance between the urchins and the kelp and other algae on which they graze.
Meoma ventricosa, known by the common names cake urchin and red heart urchin, is a large species of sea urchin which lives in shallow waters in the Caribbean. It may reach a diameter of twenty centimeters and is covered in reddish-brown spines.
These days, long-spined sea urchins are known as the gardeners of the sea. They tend the algae on the coral reefs they call home, making sure it never overwhelms their hosts. Spotting one on the ...
Psammechinus miliaris is often found covered in debris (empty shells, algae, gravel...) possibly for camouflage against predatory fishes. Brittany, France. Psammechinus miliaris is a species of sea urchin in the family Parechinidae. It is sometimes known as the green sea urchin or shore sea urchin.
Last year, sea urchins in the Caribbean started getting sick — shedding their spines, dying off and throwing reef ecosystems into chaos. “The case is closed,” said study author Mya Breitbart ...