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Benthos
 
 
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Benthos are the organisms which live on, in, or near the seabed
Seabed

The seabed is the bottom of the ocean. At the bottom of the continental slope is the continental rise, which is caused by sediment cascading down the continental slope....
, also known as the benthic zone
Benthic zone

The benthic zone is the ecological region at the lowest level of a body of water such as an ocean or a lake, including the sediment surface and some sub-surface layers....
. They live in or near marine sedimentary environments, from tidal pools along the foreshore
Intertidal zone

The intertidal zone is the area that is exposed to the air at low tide and submerged at high tide, for example, the area between tide marks. This area can include many different types of habitats, including steep rocky cliffs, sandy beaches, or wetlands ....
, out to the continental shelf
Continental shelf

The continental shelf is the extended perimeter of each continent and associated coastal plain, and was part of the continent during the glacial periods, but is undersea during Ice age such as the current epoch by relatively shallow seas and Bay....
, and then down to the abyssal depths
Abyssal zone

The abyssal zone is the abyssopelagic layer of pelagic zone that contains the very deep benthic communities near the bottom of oceans. "Abyss" is from the Greek language word meaning "bottomless sea"....
.

Many organisms adapted to deep-water pressure cannot survive in the upper parts of the water column. The pressure difference can be very significant (approximately one atmosphere
Atmosphere (unit)

The standard atmosphere is an international reference pressure defined as 101,325 Pascal and formerly used as unit of pressure . For practical purposes it has been replaced by the Bar which is 100,000 Pa....
 for each 10 meters of water depth).

Because light does not penetrate very deep ocean-water, the energy source for deep benthic ecosystems is often organic matter from higher up in the water column which drifts down to the depths.






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Benthos are the organisms which live on, in, or near the seabed
Seabed

The seabed is the bottom of the ocean. At the bottom of the continental slope is the continental rise, which is caused by sediment cascading down the continental slope....
, also known as the benthic zone
Benthic zone

The benthic zone is the ecological region at the lowest level of a body of water such as an ocean or a lake, including the sediment surface and some sub-surface layers....
. They live in or near marine sedimentary environments, from tidal pools along the foreshore
Intertidal zone

The intertidal zone is the area that is exposed to the air at low tide and submerged at high tide, for example, the area between tide marks. This area can include many different types of habitats, including steep rocky cliffs, sandy beaches, or wetlands ....
, out to the continental shelf
Continental shelf

The continental shelf is the extended perimeter of each continent and associated coastal plain, and was part of the continent during the glacial periods, but is undersea during Ice age such as the current epoch by relatively shallow seas and Bay....
, and then down to the abyssal depths
Abyssal zone

The abyssal zone is the abyssopelagic layer of pelagic zone that contains the very deep benthic communities near the bottom of oceans. "Abyss" is from the Greek language word meaning "bottomless sea"....
.

Many organisms adapted to deep-water pressure cannot survive in the upper parts of the water column. The pressure difference can be very significant (approximately one atmosphere
Atmosphere (unit)

The standard atmosphere is an international reference pressure defined as 101,325 Pascal and formerly used as unit of pressure . For practical purposes it has been replaced by the Bar which is 100,000 Pa....
 for each 10 meters of water depth).

Because light does not penetrate very deep ocean-water, the energy source for deep benthic ecosystems is often organic matter from higher up in the water column which drifts down to the depths. This dead and decaying matter
Detritus

Detritus is a biological term used to describe dead or waste organic material.Detritus may also refer to:* Detritus , a geological term used to describe the particles of rock produced by weathering...
 sustains the benthic food chain
Food chain

Food chains, also called, food networks and/or trophic social networks, describe the eating relationships between species within an ecosystem....
; most organisms in the benthic zone are scavengers or detritivores.

The term benthos comes from the Greek
English words of Greek origin

The Greek language has contributed to the English language vocabulary in three ways:#directly as an immediate donor,#indirectly through other intermediate language, as an original donor , and...
 for "depths of the sea". Benthos is also used in freshwater biology
Freshwater biology

Freshwater ecosystems are among the earth's aquatic ecosystems. They include Lentic system ecology and ponds, Lotic system ecology, streams and spring s, and wetlands....
 to refer to organisms at the bottom of freshwater bodies of water
Body of water

A body of water is any significant accumulation of water, usually covering the Earth or another planet. The term body of water most often refers to large accumulations of water, such as oceans, seas, and lakes, but it may also include smaller pools of water such as ponds, puddles or wetlands....
, such as lakes, rivers, and streams.

Food sources

The main food sources for benthos are plankton
Plankton

Plankton consist of any drifting organisms that inhabit the pelagic zone of oceans, seas, or bodies of fresh water. Plankton are defined by their ecological niche rather than their Phylogenetics or taxonomy classification....
 and organic runoff from land. The depth of water, temperature and salinity, and type of local substrate all affect what benthos is present. In coastal waters and other places where light reaches the bottom, benthic photosynthesizing
Photosynthesis

File:Seawifs global biosphere.jpgPhotosynthesis is a metabolic pathway that converts carbon dioxide into organic compounds, especially sugars, using the energy from sunlight....
 diatoms can proliferate. Filter feeder
Filter feeder

Filter feeders are animals that feed by straining suspended matter and food particles from water, typically by passing the water over a specialized filtering structure....
s, such as sponges and pelecypods, dominate hard, sandy bottoms. Deposit eaters, such as polychaete
Polychaete

The Polychaeta or polychaetes are a class of annelid worms, generally marine. Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles, called chaetae, which are made of chitin....
s, populate softer bottoms. Fish, sea star
Sea star

Sea stars, also known as starfish, are echinoderms belonging to the class Asteroidea. The names "sea star" and "starfish" are sometimes differentiated, with "starfish" used in a broader sense to include the closely related brittle stars, which make up the class Ophiuroidea, as well as excluding sea stars which do not have five ar...
s, snail
Snail

The word snail is a common name for almost all members of the molluscan class Gastropoda that have coiled animal shells in the adult stage. When the word snail is used in a general sense, it includes sea snails, land snails and freshwater snails....
s, cephalopod
Cephalopod

The cephalopods are the mollusc class Cephalopoda characterized by bilateral symmetry, a prominent head, and a modification of the mollusk foot, a muscular hydrostat, into the form of cephalopod arms or tentacles....
s, and crustacean
Crustacean

Crustaceans are a large group of arthropods, comprising almost 52,000 described species , and are usually treated as a subphylum . They include various familiar animals, such as crabs, lobsters, crayfish, shrimp, krill and barnacles....
s are important predators and scavengers.

Benthic organisms, such as sea star
Sea star

Sea stars, also known as starfish, are echinoderms belonging to the class Asteroidea. The names "sea star" and "starfish" are sometimes differentiated, with "starfish" used in a broader sense to include the closely related brittle stars, which make up the class Ophiuroidea, as well as excluding sea stars which do not have five ar...
s, oyster
Oyster

The common name oyster is used for a number of different groups of bivalve mollusks, most of which live in marine habitats or brackish water....
s, clam
Clam

Clam is a word which can be used for all, some, or only a few species of bivalve mollusks; the word is a common name which has no real Taxonomy significance in biology....
s, sea cucumber
Sea cucumber

Holothuroidea is a class of marine animals with an elongated body and leathery skin, which is found on the sea floor worldwide. Many holothurian species and genera, informally known as sea cucumbers, are targeted for human consumption....
s, brittle star
Brittle star

Brittle stars, or Ophiuroidea, are echinoderms, closely related to sea stars. They crawl across the seafloor using their flexible arms for locomotion....
s and sea anemone
Sea anemone

Sea anemones are a group of water dwelling, predation animals of the order Actiniaria; they are named after the anemone, a terrestrial flower....
s, play an important role as a food source for fish
Fish

A fish is any marine biology vertebrate animal that is typically ectothermic , covered with scale , and equipped with two sets of paired fins and several unpaired fins....
 and human
Human

A human being, also human or man, is a member of a species of bipedalism primates in the family Hominidae . Mitochondrial DNA evidence indicates that modern humans originated in east Africa about 200,000 years ago....
s.

By size


Macrobenthos
Macrobenthos are the larger, more visible, benthos that are greater than 1 mm in size. Some examples are polychaete worms
Polychaete

The Polychaeta or polychaetes are a class of annelid worms, generally marine. Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles, called chaetae, which are made of chitin....
, bivalves, echinoderm
Echinoderm

Echinoderms are a Phylum of Marine animals . Echinoderms are found at every ocean depth, from the intertidal zone to the abyssal zone.Aside from the problematic Arkarua, the first definitive members of the phylum appeared near the start of the Cambrian period....
s, sea anemone
Sea anemone

Sea anemones are a group of water dwelling, predation animals of the order Actiniaria; they are named after the anemone, a terrestrial flower....
s, coral
Coral

Corals are marine organisms from the class Anthozoa and exist as small sea anemone?like polyps, typically in colonies of many identical individuals....
s, sponges, sea squirts, turbellarians and larger crustacean
Crustacean

Crustaceans are a large group of arthropods, comprising almost 52,000 described species , and are usually treated as a subphylum . They include various familiar animals, such as crabs, lobsters, crayfish, shrimp, krill and barnacles....
s such as crab
Crab

Crabs are Decapoda crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" , or where the reduced abdomen is entirely hidden under the thorax....
s, lobster
Lobster

Clawed lobsters compose a family of large marine crustaceans. Lobsters are economically important as seafood, forming the basis of a global industry that nets United States dollar1.8 billion in trade annually....
s and cumaceans.

Meiobenthos
Meiobenthos
Meiobenthos

Meiofauna are small benthos invertebrates that live in both marine and fresh water environments . The term Meiofauna loosely defines a group of organisms by their size, larger than Microfauna but smaller than Macrofauna, rather than a taxonomic grouping....
 are tiny benthos that are less than 1 mm but greater than 32 µm in size. Some examples are nematode
Nematode

The "roundworms" or "nematodes" are the most diverse phylum of body cavity, and one of the most diverse of all animals. Nematode species are very difficult to distinguish; over 80,000 have been described, of which over 15,000 are parasite....
s, foraminiferans, water bears
Tardigrade

Tardigrades form the phylum Tardigrada, part of the superphylum Ecdysozoa. They are microscopic, water-dwelling, segmented animals with eight legs....
, gastrotrich
Gastrotrich

The gastrotrichs are a phylum of microscopic animals abundant in fresh water and marine environments. Most fresh water species are part of the periphyton and benthos....
es and smaller crustacean
Crustacean

Crustaceans are a large group of arthropods, comprising almost 52,000 described species , and are usually treated as a subphylum . They include various familiar animals, such as crabs, lobsters, crayfish, shrimp, krill and barnacles....
s such as copepod
Copepod

Copepods are a group of small crustaceans found in the sea and nearly every fresh water habitat . Many species are planktonic , but more are benthos , and some continental species may live in limno-terrestrial habitats and other wet terrestrial places, such as swamps, under leaf fall in wet forests, bogs, springs, ephemeral ponds and puddle...
s and ostracodes.
Microbenthos
Microbenthos are microscopic benthos that are less than 32 µm in size. Some examples are bacteria
Bacteria

The Bacteria are a large group of unicellular microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals....
, diatoms, ciliate
Ciliate

The ciliates are a group of protists characterized by the presence of hair-like organelles called cilium, which are identical in structure to flagellum but typically shorter and present in much larger numbers with a different undulating pattern than flagella....
s, amoeba
Amoeba

Amoeba is a term used either to describe protists that move by crawling via pseudopods, or to refer to a genus that includes species that move by this mechanism....
, flagellate
Flagellate

Flagellates are cell s with one or more whip-like organelles called flagellum. Some cells in animals may be flagellate, for instance the spermatozoa of most phyla....
s

By type

Libr0409
Zoobenthos
Zoobenthos
Zoobenthos

Zoobenthos are the animal subset of organisms more generally referred to as benthos....
 are animals belonging to the benthos.

Phytobenthos
Phytobenthos are plants belonging to the benthos.

By location


Epibenthos
Epibenthos live on top of the sediment

Hyperbenthos
Hyperbenthos live just above the sediment

See also

  • Aphotic zone
    Aphotic zone

    The aphotic zone is the portion of a lake or ocean where there is little or no sunlight.It is formally defined as the depths beyond which less than 1% of sunlight penetrates....
  • Bottom feeder
    Bottom feeder

    A demersal fish is a fish that feeds on or near the bottom of the ocean or a deep lake in the demersal zone. Demersal fish are also known as bottom feeders, groundfish or Benthic zone fish, and may be contrasted with Pelagic zone....
  • Deep sea
    Deep sea

    File:Nur04506.jpgThe deep sea, or deep layer, is the lowest layer in the ocean, existing below the thermocline, at a depth of 1000 fathoms or more....
  • Intertidal ecology
    Intertidal ecology

    Intertidal ecology is the study of intertidal zone ecosystems, where organisms live between the low and high tide lines. At low tide, the intertidal is exposed whereas at high tide, the intertidal is underwater ....
  • Littoral
    Littoral

    In coastal environments and biomes, the littoral zone extends from the high water mark, which is rarely inundated, to shoreline areas that are permanently submerged....
  • Neritic zone
    Neritic zone

    The neritic zone, also called the Littoral zone#Sublittoral zone, is the part of the ocean extending from the low tide mark to the edge of the continental shelf, with a relatively shallow depth extending to about 200 meters ....
  • Pelagic zone
    Pelagic zone

    Any water in the sea that is not close to the bottom is in the pelagic zone. The word pelagic comes from the Greek language p??a??? or p?lagos, which means open sea....
  • Photic zone
    Photic zone

    The photic zone or euphotic zone is the depth of the water in a lake or ocean, that is exposed to sufficient sunlight for photosynthesis to occur....
  • Profundal zone
    Profundal zone

    The profundal zone is a deep zone of a body of water, such as an ocean or a lake, located below the range of effective light penetration. This is typically below the thermocline, the vertical zone in the water through which temperature drops rapidly....
  • Sediment Profile Imagery
    Sediment Profile Imagery

    Sediment Profile Imagery is an underwater technique for photographing the interface between the seabed and the overlying water. The technique is used to measure or estimate biological, chemical, and physical processes occurring in the first few centimetres of sediment, Groundwater, and the important benthic boundary layer of water....
     (SPI)
  • Stream bed
    Stream bed

    A stream bed is the channel bottom of a stream, river or creek; the physical confine of the normal water flow. The lateral confines or channel margins, during all but flood stage, are known as the stream banks or river banks....


Contrast the terms plankton
Plankton

Plankton consist of any drifting organisms that inhabit the pelagic zone of oceans, seas, or bodies of fresh water. Plankton are defined by their ecological niche rather than their Phylogenetics or taxonomy classification....
 (the organisms that float or drift within the water), nekton
Nekton

Nekton refers to the aggregate of actively swimming aquatic organisms in a body of water able to move independently of water currents. Nekton are contrasted with 'plankton' which refers to the aggregate of passively floating, drifting, or somewhat motile organisms occurring in a body of water, primarily comprising tiny algae and bacteria, s...
 (the organisms that swim (powerfully) in the water), and neuston
Neuston

Neuston is the collective term for the organisms that float on the top of water or live right under the surface. Neustons are made up of some species of fish , beetles , protozoans, bacteria and spiders ....
 (the organisms that float on the water).

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