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Holothurians
Sea cucumbers are echinoderms from the class Holothuroidea (). They are marine animals with a leathery skin and an elongated body containing a single, branched gonad. Sea cucumbers are found on the sea floor worldwide. The number of holothurian () species worldwide is about 1,717, with the greatest number being in the Asia-Pacific region. Many of these are gathered for human consumption and some species are cultivated in aquaculture systems. The harvested product is variously referred to as '' trepang'', ''namako'', ''bêche-de-mer'', or ''balate''. Sea cucumbers serve a useful role in the marine ecosystem as they help recycle nutrients, breaking down detritus and other organic matter, after which bacteria can continue the decomposition process. Like all echinoderms, sea cucumbers have an endoskeleton just below the skin, calcified structures that are usually reduced to isolated microscopic ossicles (or sclerietes) joined by connective tissue. In some species these can sometim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Actinopyga Echinites
''Actinopyga echinites'', commonly known as the brownfish or deep water redfish, is a species of sea cucumber in the family Holothuriidae. It is native to the tropical Indo-Pacific region and is harvested for food. Description ''Actinopyga echinites'' grows to a length of about . It is widest in the middle, tapering slightly at both ends; the dorsal surface is arched while the ventral surface is flattened. The leathery skin is rough, being covered in papillae. The skin is strengthened by the presence of spicules, microscopic spike-like structures, which in this species are shaped like large rods. The colour of this sea cucumber is brown above and orange-brown below, and the upper surface often has sand adhering to it. The anus is surrounded by five beige anal teeth, and the pinkish Cuvierian tubules are occasionally discharged through the anus when the animal is stressed. Distribution and habitat ''Actinopyga echinites'' is found off the coasts of Asia and Africa, in the tropi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dendrochirotida
Dendrochirotida are an order of sea cucumbers. Members of this order have branched tentacles and are suspension feeders. Examples include '' Thyonella'' and ''Cucumaria''. Characteristics Holothurians in this order are characterised by ten to thirty much branched tentacles which are sometimes digitate. They also have ring structures composed of ten calcareous plates circling the pharynx. They have both retractor and introvert muscles which means they can retract the tentacles into the mouth when not feeding. The body wall is either firm with large ossicles or of a soft consistency with few ossicles. In some genera the animals attach themselves to hard surfaces but in others they burrow into soft sediments. Prey is captured by the sticky tentacles and transferred to the mouth. The larvae are lecithotrophic, not feeding on plankton but surviving only on materials already present in the eggs until they settle and become juveniles. Taxonomy Order: Dendrochirotida * family Cucumariidae ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
World Register Of Marine Species
The World Register of Marine Species (WoRMS) is a taxonomic database that aims to provide an authoritative and comprehensive list of names of marine organisms. Content The content of the registry is edited and maintained by scientific specialists on each group of organism. These taxonomists control the quality of the information, which is gathered from the primary scientific literature as well as from some external regional and taxon-specific databases. WoRMS maintains valid names of all marine organisms, but also provides information on synonyms and invalid names. It is an ongoing task to maintain the registry, since new species are constantly being discovered and described by scientists; in addition, the nomenclature and taxonomy of existing species is often corrected or changed as new research is constantly being published. Subsets of WoRMS content are made available, and can have separate badging and their own home/launch pages, as "subregisters", such as the ''World List o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pelagothuriidae
Pelagothuriidae is a family of deep-sea swimming sea cucumbers. They are somewhat unusual in appearance, in comparison with other sea cucumbers, having numerous appendages, including conical papillae and leaf-like tentacles. Most of them are benthopelagic, which means that they are able to swim for a time from the bottom : the species '' Pelagothuria natatrix'' is the only true pelagic holothurian (and echinoderm, to date) ; it looks like a jellyfish. Most members of the order inhabit deep-sea environments, like ''Enypniastes''. Classification Family: Pelagothuriidae * genus ''Enypniastes'' Théel, 1882 * genus ''Pelagothuria ''Pelagothuria'' is a genus of sea cucumbers in the family Pelagothuriidae. It is monotypic, being represented by the single species ''Pelagothuria natatrix''. Characteristics This sea cucumber is somewhat unusual in appearance in comparison ...'' Ludwig, 1893 References * * Notes Echinoderm families {{Holothuroidea-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pelagothuria Natatrix
''Pelagothuria'' is a genus of sea cucumbers in the family Pelagothuriidae. It is monotypic, being represented by the single species ''Pelagothuria natatrix''. Characteristics This sea cucumber is somewhat unusual in appearance in comparison with other sea cucumbers (and even within its family), as it looks more like a jellyfish with its large umbrella-like swimming structure supported by a ring of around 12 highly modified oral tentacles, its small tapered body and its swimming position with the mouth on top. The body is translucent with a pale purple pigmentation. The mouth is surrounded by around 15 short feeding tentacles like any sea cucumber, and the veil can be contracted like jellyfishes do (it is interrupted at the central ventral radius). The animal seems to reach around 16 cm in total diameter. This species constitutes the only true pelagic holothurian (and even echinoderm) known to date. However, its swimming seems mostly passive, more like slightly controlled ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pelagic
The pelagic zone consists of the water column of the open ocean, and can be further divided into regions by depth (as illustrated on the right). The word ''pelagic'' is derived . The pelagic zone can be thought of as an imaginary cylinder or water column between the surface of the sea and the bottom. Conditions in the water column change with depth: pressure increases; temperature and light decrease; salinity, oxygen, micronutrients (such as iron, magnesium and calcium) all change. Marine life is affected by bathymetry (underwater topography) such as the seafloor, shoreline, or a submarine seamount, as well as by proximity to the boundary between the ocean and the atmosphere at the ocean surface, which brings light for photosynthesis, predation from above, and wind stirring up waves and setting currents in motion. The pelagic zone refers to the open, free waters away from the shore, where marine life can swim freely in any direction unhindered by topographical constraints. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ossicle (echinoderm)
Ossicles are small calcareous elements embedded in the dermis of the body wall of echinoderms. They form part of the endoskeleton and provide rigidity and protection. They are found in different forms and arrangements in sea urchins, starfish, brittle stars, sea cucumbers, and crinoids. The ossicles and spines (which are specialised sharp ossicles) are the only parts of the animal likely to be fossilized after an echinoderm dies. Formation Ossicles are created intracellularly by specialised secretory cells known as sclerocytes in the dermis of the body wall of echinoderms. Each ossicle is composed of microcrystals of calcite arranged in a three-dimensional lattice known as a stereom. Under polarized light the ossicle behaves as if it were a single crystal because the axes of all the crystals are parallel. The space between the crystals is known as the stroma and allows entry to sclerocytes for enlargement and repair. The honeycomb structure is light but tough and collagenous li ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endoskeleton
An endoskeleton (From Greek ἔνδον, éndon = "within", "inner" + σκελετός, skeletos = "skeleton") is an internal support structure of an animal, composed of mineralized tissue. Overview An endoskeleton is a skeleton that is on the inside of a body, like humans, dogs, or some fish. The endoskeleton develops within the skin or in the deeper body tissues. The vertebrate endoskeleton is basically made up of two types of tissues (bone and cartilage). During early embryonic development the endoskeleton is composed of notochord and cartilage. The notochord in most vertebrates is replaced by the vertebral column and cartilage is replaced by bone in most adults. In three phyla and one subclass of animals, endoskeletons of various complexity are found: Chordata, Echinodermata, Porifera, and Coleoidea. An endoskeleton may function purely for support (as in the case of sponges), but often serves as an attachment site for muscle and a mechanism for transmitting muscular forces. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Decomposition
Decomposition or rot is the process by which dead organic substances are broken down into simpler organic or inorganic matter such as carbon dioxide, water, simple sugars and mineral salts. The process is a part of the nutrient cycle and is essential for recycling the finite matter that occupies physical space in the biosphere. Bodies of living organisms begin to decompose shortly after death. Animals, such as worms, also help decompose the organic materials. Organisms that do this are known as decomposers or detritivores. Although no two organisms decompose in the same way, they all undergo the same sequential stages of decomposition. The science which studies decomposition is generally referred to as ''taphonomy'' from the Greek word ''taphos'', meaning tomb. Decomposition can also be a gradual process for organisms that have extended periods of dormancy. One can differentiate abiotic decomposition from biotic decomposition ( biodegradation). The former means "the degradat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bacteria
Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among the first life forms to appear on Earth, and are present in most of its habitats. Bacteria inhabit soil, water, Hot spring, acidic hot springs, radioactive waste, and the deep biosphere of Earth's crust. Bacteria are vital in many stages of the nutrient cycle by recycling nutrients such as the nitrogen fixation, fixation of nitrogen from the Earth's atmosphere, atmosphere. The nutrient cycle includes the decomposition of cadaver, dead bodies; bacteria are responsible for the putrefaction stage in this process. In the biological communities surrounding hydrothermal vents and cold seeps, extremophile bacteria provide the nutrients needed to sustain life by converting dissolved compounds, such as hydrogen sulp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organic Matter
Organic matter, organic material, or natural organic matter refers to the large source of carbon-based compounds found within natural and engineered, terrestrial, and aquatic environments. It is matter composed of organic compounds that have come from the feces and remains of organisms such as plants and animals. Organic molecules can also be made by chemical reactions that do not involve life. Basic structures are created from cellulose, tannin, cutin, and lignin, along with other various proteins, lipids, and carbohydrates. Organic matter is very important in the movement of nutrients in the environment and plays a role in water retention on the surface of the planet. Formation Living organisms are composed of organic compounds. In life, they secrete or excrete organic material into their environment, shed body parts such as leaves and roots and after organisms die, their bodies are broken down by bacterial and fungal action. Larger molecules of organic matter can be formed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Detritus
In biology, detritus () is dead particulate organic material, as distinguished from dissolved organic material. Detritus typically includes the bodies or fragments of bodies of dead organisms, and fecal material. Detritus typically hosts communities of microorganisms that colonize and decompose (i.e. remineralize) it. In terrestrial ecosystems it is present as leaf litter and other organic matter that is intermixed with soil, which is denominated " soil organic matter". The detritus of aquatic ecosystems is organic material that is suspended in the water and accumulates in depositions on the floor of the body of water; when this floor is a seabed, such a deposition is denominated " marine snow". Theory The corpses of dead plants or animals, material derived from animal tissues (e.g. molted skin), and fecal matter gradually lose their form due to physical processes and the action of decomposers, including grazers, bacteria, and fungi. Decomposition, the process by w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
