Brittle stars feed on dead animals, plankton, and even fish. They are however, decomposers, s0 this food eventually gets broken down and put back out into the ecosystem. (Picture from https://upload.wikimedia.org/wikipedia/en/6/64/Greenbrittlestar.jpg) Sea Slug (Holothuroidea)
Full Answer
Why are brittle stars important to the ecosystem?
Brittle stars play a pretty important role in the food web. They are known as “seafloor ecosystem engineers,” meaning they reshape the sediment shape on the seafloor, which in turn influences the distribution of other seafloor species. Brittle stars use their mouths (found on the underbelly of their disks) to munch on small organisms and detritus.
What do brittle stars use their arms for?
They extend one arm out and use the other four as anchors. Brittle stars will eat small suspended organisms if available. In large, crowded areas, brittle stars eat suspended matter from prevailing seafloor currents. In basket stars, the arms are used to sweep food rhythmically to the mouth.
How does fission occur in a brittle star?
Fission. Regrowth of both the lost part of the disk and the arms occur which yields an animal with three large arms and three small arms during the period of growth. The West Indian brittle star, Ophiocomella ophiactoides, frequently undergoes asexual reproduction by fission of the disk with subsequent regeneration of the arms.
What happens if a brittle star loses an arm?
Brittle stars also tend to sacrifice individual arms when threatened. A severed arm can go on moving for hours. This appears to distract the attention of a predator from the fleeing brittle star. Although a lost arm soon regenerates under good nutritional conditions, such a loss should still be avoided.
How do brittle stars excrete waste?
Like sea stars, brittle stars have their mouth on the underside. They filter sand and mud from the ocean floor, feeding on detritus. Their digestive system is quite simple. They have a stomach but no intestine or anus, so any waste is excreted from the mouth.
Are brittle starfish poisonous?
Brittle stars are not used as food, though they are not toxic, because of their strong skeleton. Even if some species have blunt spines, no brittlestar is known to be dangerous, nor venomous.
Why are brittle stars important?
Brittle stars play an important role in the Arctic food web. First, they are known to be seafloor ecosystem engineers. They reshape the seafloor sediment surface and influence the distribution of other seafloor species. They also provide nutrition to fish, sea stars and crab predators.
What do brittle stars eat?
Brittle stars are scavengers that eat algae, plants, fish feces and other detritus as well as detritus and small oceanic organisms such as plankton.
Can you touch a brittle starfish?
Yes they can sting you or even a fish, but as long as they don't get really large, they are generally considered good cleaners to have. Personally, I don't like them because I have my hands in my tank way too often but that is just me. Brittle stars can sting?
What eats brittle starfish?
captain dunsel. Bumble Bee Shrimp will eat away at brittle stars. They go at them like ants and nibble away at the legs first. Bongo shrimp have been known to prey upon them as well.
Do brittle stars have brains?
Starfishlike brittle stars have five thin arms and no central brain, but even so, they move in a carefully coordinated fashion similar to four-limbed animals (including humans).
Will brittle stars eat coral?
Most brittle stars are reef safe, ignoring corals and other crustaceans while cleaning up leftovers and detritus around the tank. Brittle starfish don't require a specialized diet.
How long does it take for a brittle star to regrow an arm?
Starfish regeneration across species follows a common three-phase model and can take up to a year or longer to complete. Though regeneration is used to recover limbs eaten or removed by predators, starfish are also capable of autotomizing and regenerating limbs to evade predators and reproduce.
Why do brittle stars break off their arms?
BRITTLESTARS: A CALL TO ARMS Their name comes from the fact that their arms are easily broken off. And, in fact, they are perfectly capable of breaking those arms off themselves as a distraction while escaping predators – and then growing new ones. And, when they have those arms, they make wily use of them.
Do brittle stars have eyes?
In the 23 August issue of Nature, a team of scientists reports that a brittle star species has turned its skeleton into a vast array of microscopic lenses that cover half its body. The lenses are the core of a remarkable visual system that allows the animals to find dark hiding places on the ocean bottom.
Can brittle stars be exposed to air?
Exposure to air does not harm sea stars, nor does touching them with your bare hands (though it's a good idea to avoid handling anything in your tank as much as possible).
What starfish are poisonous?
The crown-of-thorns starfish receives its name from venomous thorn-like spines that cover its upper surface, resembling the biblical crown of thorns. It is one of the largest starfish in the world....Crown-of-thorns starfishFamily:AcanthasteridaeGenus:AcanthasterSpecies:A. planciBinomial name7 more rows
Are starfish poisonous to eat?
Can You Eat Starfish Raw? Eating raw starfish can cause food poisoning. Accordingly, it's recommended to prepare a live starfish and then cook and eat it like you would a lobster.
Are brittle starfish reef safe?
Most brittle stars are reef safe, ignoring corals and other crustaceans while cleaning up leftovers and detritus around the tank. Brittle starfish don't require a specialized diet. They'll accept chopped portions of any raw, meaty seafood.
What happens if you touch a starfish?
Since starfish cannot stay in the water and breathe, they suffer from carbon monoxide poisoning, which causes them to die from asphyxiation. Another common cause of death is stress from handling them too much. How long can a starfish last out of water?
About
Upon first glance, brittle stars may look like starfish but don’t be fooled! Although brittle stars and starfish are closely related, they are completely different species.
Status and Conservation
Brittle stars live in a variety of habitats around the world. There are 73 species in the Arctic alone! There, they live at various depths, with some species occurring deeper than 3,500 meters. In the Alaskan Arctic, you can find most species on shallower ocean shelf waters.
Brittle stars are an echinoderm with whip-like arms
Jennifer Kennedy, M.S., is an environmental educator specializing in marine life. She serves as the executive director of the Blue Ocean Society for Marine Conservation.
Description
A brittle star is made up of an obvious central disk and five or six arms. The central disk is small and clearly offset from its arms, which are long and slender.
Species
The World Ophiuroidea Database lists over 2,000 species of brittle stars accepted in the Class Ophiuridea, the taxonomic class which contains brittle stars, as well as basket stars and snake stars (Kingdom: Animalia, Phylum: Echinodermata, Class: Ophiuroidea, Order: Ophiurida). Ophiuroidea is the largest class among extant Echinodermata.
Habitat and Range
Brittle stars occur in all the world's oceans from the deep sea to intertidal zones, and including salt and brackish polar areas, temperate, and tropical waters. The region with the highest species richness of brittle stars is the Indo-Pacific region with 825 species at all depths. The Arctic has the lowest number of species: 73.
Diet
Brittle stars feed on detritus and small oceanic organisms such as plankton , small mollusks, and even fish. Some brittle stars will raise themselves on their arms, and when fish get close enough, they wrap them in a spiral and eat them.
Behavior
Brittle stars can drop an arm when being attacked by a predator. This process is known as autotomy or self-amputation, and when the star is threatened, the nerve system tells the mutable collagenous tissue near the base of the arm to disintegrate.
Reproduction
There are male and female brittle stars, although it is not obvious which sex a brittle star is without looking at its genitals, which are located inside its central disk. Some brittle stars reproduce sexually, by releasing eggs and sperm into the water.
What do you feed brittle starfish?
Because they are scavengers, if kept in aquarium brittle starfish will feed on leftovers and clean the aquarium of detritus created by other fish. But if they don’t have enough companions to provide with enough to eat, you will need to give them additional food. Most of the brittle star species are not picky eaters, they are omnivorous.
Do brittle stars eat coral?
In general, brittle stars will not eat corals, and just leave them be. Some species, that are big enough, will feed on dead or dying shrimps and other small crustaceans in absence of other food. If you notice that your brittle stars are eating soft coral it may mean that you have two problems with your aquarium.
How do brittle stars survive?
Because they are bottom dwellers, to survive and protect themselves from predators they bury in the seabed or hide in nooks and crevices they may find. Often they will leave just one of their arms exposed in search of a quick bite that currents may bring them.
Do brittle stars eat phytoplankton?
Some brittle star species in the wild rhythmically wave one of their arms and thus catch detritus, phytoplanktons, and zooplanktons if they are present in the water sorrrounding them. They are omnivorous scavengers which means that they will eat almost any decomposing organic material, that includes the dead or dying phytoplanktons.
Can brittle starfish kill fish?
Though they are preferably scavengers and also feed on detritus, some larger species do hunt and prey on other sea creatures. Mostly those are smaller sea animals, like small crustaceans and mollusks. Brittle fish are nocturnal animals and larger ones may attack shrimps, squids, and smaller fish when they are sleeping or are sick and dying.
Can you touch a brittle starfish?
Brittle stars are safe for touching, but touching them may not be safe for them. Just like their starfish cousins, brittle stars can’t “hold” their breath longer than 30 seconds. Picked out of water will be in danger of dying prematurely.
Do brittle stars bite?
While brittle stars have mouths surrounded by five jaws, and larger species of them may attack smaller sea creatures, they do not bite. In that sense, you are very safe from them. If you handle them you present a much bigger danger for them as you can easily injure them.
Overview
Anatomy
Of all echinoderms, the Ophiuroidea may have the strongest tendency toward five-segment radial (pentaradial) symmetry. The body outline is similar to that of starfish, in that ophiuroids have five arms joined to a central body disk. However, in ophiuroids, the central body disk is sharply marked off from the arms.
Range
The ophiuroids diverged in the Early Ordovician, about 500 million years ago. Ophiuroids can be found today in all of the major marine provinces, from the poles to the tropics. Basket stars are usually confined to the deeper parts of this range; Ophiuroids are known even from abyssal (>6000 m) depths. However, brittle stars are also common members of reef communities, where they hide u…
Reproduction
The sexes are separate in most species, though a few are hermaphroditic or protandric. The gonads are located in the disk, and open into pouches between the arms, called genital bursae. Fertilisation is external in most species, with the gametes being shed into the surrounding water through the bursal sacs. An exception is the Ophiocanopidae, in which the gonads do not open into bursa…
Locomotion
Brittle stars use their arms for locomotion. Brittle stars move fairly rapidly by wriggling their arms which are highly flexible and enable the animals to make either snake-like or rowing movements. However, they tend to attach themselves to the sea floor or to sponges or cnidarians, such as coral. They move as if they were bilaterally symmetrical, with an arbitrary leg selected as the symmetry axis and the other four used in propulsion. The axial leg may be facing or trailing the d…
Bioluminescence
Over 60 species of brittle stars are known to be bioluminescent. Most of these produce light in the green wavelengths, although a few blue-emitting species have also been discovered. Both shallow-water and deep-sea species of brittle stars are known to produce light. Presumably, this light is used to deter predators .
Ecology
Brittle stars live in areas from the low-tide level downwards. Six families live at least 2 m deep; the genera Ophiura, Amphiophiura, and Ophiacantha range below 4 m. Shallow species live among sponges, stones, or coral, or under the sand or mud, with only their arms protruding. Two of the best-known shallow species are the green brittle star (Ophioderma brevispina), found from Massachusetts to Brazil, and the common European brittle star (Ophiothrix fragilis). Deep-water …
Diversity and taxonomy
Between 2,064 and 2,122 species of brittle stars are currently known, but the total number of modern species may be over 3,000. This makes brittle stars the most abundant group of current echinoderms (before sea stars). Around 270 genera are known, these are distributed in 16 families, which makes them at the same time a relatively poorly diversified group structurally, compared with the …
Description
Species
- The World Ophiuroidea Database lists over 2,000 species of brittle stars accepted in the Class Ophiuridea, the taxonomic class which contains brittle stars, as well as basket stars and snake stars (Kingdom: Animalia, Phylum: Echinodermata, Class: Ophiuroidea, Order: Ophiurida). Ophiuroidea is the largest class among extant Echinodermata. Traditionally, brittle stars are in a …
Habitat and Range
- Brittle stars occur in all the world's oceans from the deep sea to intertidal zones, and including salt and brackish polar areas, temperate, and tropical waters. The region with the highest species richness of brittle stars is the Indo-Pacific region with 825 species at all depths. The Arctic has the lowest number of species: 73. In some areas, they are found residing in large numbers in de…
Diet
- Brittle stars feed on detritus and small oceanic organisms such as plankton, small mollusks, and even fish. Some brittle stars will raise themselves on their arms, and when fish get close enough, they wrap them in a spiral and eat them. Brittle stars may also feed by lifting up their arms to trap tiny particles and algae ("marine snow") using the mucous strands on their tube feet. Then, the t…
Behavior
- Brittle stars can drop an arm when being attacked by a predator. This process is known as autotomy or self-amputation, and when the star is threatened, the nerve system tells the mutable collagenous tissue near the base of the arm to disintegrate. The wound heals, and then the arm regrows, a process which can take weeks to months, depending upon th...
Reproduction
- There are male and female brittle stars, although it is not obvious which sex a brittle star is without looking at its genitals, which are located inside its central disk. Some brittle stars reproduce sexually, by releasing eggs and sperm into the water. This results in a free-swimming larva called an ophiopluteus, which eventually settles to the bottom and forms a brittl…
Conservation Status
- The International Union for Conservation of Nature (IUCN) does not list any brittle star. The WoRMS Catalog of Life includes a total of over 2,000 species but does not identify any endangered species. Perceived threats include pollution and habitat loss.
Sources
- Clark, M. S., and T. Souster. "Slow Arm Regeneration in the Antarctic Brittle Star Ophiura Crassa (Echinodermata, Ophiuroidea)." Aquatic Biology16.2 (2012): 105-13. Print.
- Coulombe, Deborah. "The Seaside Naturalist: A Guide to Study at the Seashore." New York: Simon & Schuster, 1990.
- Denny, Mark W. and Steven D. Gaines (eds). "Encyclopedia of Tidepools and Rocky Shores." U…
- Clark, M. S., and T. Souster. "Slow Arm Regeneration in the Antarctic Brittle Star Ophiura Crassa (Echinodermata, Ophiuroidea)." Aquatic Biology16.2 (2012): 105-13. Print.
- Coulombe, Deborah. "The Seaside Naturalist: A Guide to Study at the Seashore." New York: Simon & Schuster, 1990.
- Denny, Mark W. and Steven D. Gaines (eds). "Encyclopedia of Tidepools and Rocky Shores." University of California Press, 2007.
- Mah, Chris. "Brittle Star Domination! When Ophiuroids Carpet the Murky Deep!" The Echinoblog, September 24, 2013.
