Biodiversity & Conservation

MarLIN Glossary

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B

Barbel
Fleshy filament growing from the mouth or snout of a fish. Also the common name for a member of the carp family (OED, 2005).

Barbels
Plural of 'barbel'.

Barnacle
A group of crustaceans that live permanently attached to a substratum by the anterior potion of their head (Hayward et al., 1996). Two forms are typical. The goose barnacles hang from the substratum by a leathery stalk with the rest of the body protected (to varying degrees) by calcareous shell plates. The acorn barnacles are attached directly to the substratum and protected by tightly fitting calcareous shell plates.

Barnacles
Plural of 'barnacle'

Bathyal
Pertaining to the sea floor between 200 m and 4000 m (Lincoln & Boxshall, 1987).

Bathydemersal
Lives near the bottom of a deep body of water (usually 200 to 2000m) (Lincoln et al., 1998).

Bathymetry
Measurement of ocean or lake depth and the study of floor topography (Lincoln & Boxshall, 1987).

Beach
The strip of land along the margin of a body of water that is washed by waves or tides sufficiently to inhibit all or most terrestrial plant growth (based on Lincoln & Boxshall, 1987). The term is taken to include the entire littoral zone, including the supralittoral fringe, or splash zone, and is generally interpreted as referring to sediment (or mobile boulders) rather than bedrock shores.

Beak
1) A horny projecting jaw such as the jaw of turtles and squid, the narrow snout of dolphins or some whales or the bill of birds. 2) Small, beak like part of shell valve along or above the hinge, represents earliest part of shell and continues to form umbo. May be used as synonym for umbo (Stachowitsch, 1992).

Bedrock
Any stable hard substratum, not separated into boulders or smaller sediment units.

Benthopelagic
Lives in the water column but is associated with the sea floor (Baretta-Bekker et al., 1992).

Benthos
Those organisms attached to, or living on, in or near, the seabed, including that part which is exposed by tides as the littoral zone (based on Lincoln & Boxshall, 1987).

Bioaccumulation
The ability of organisms to retain and concentrate substances from their environment. The gradual build-up of substances in living tissue; usually used in referring to toxic substances; may result from direct absorption from the environment or through the food-chain. Cf. 'biomagnification'.

Biocenosis
See 'biocoenosis'

Bioclastic Sediment
A sediment composed of broken fragments of organic skeletal material (Lincoln et al., 1998).

Biocoenosis
A term used in continental Europe which can be considered roughly equivalent to 'community' as suggested by Cain (1939), i.e. "a term of convenience which is employed to designate sociological units to every degree from the simplest one-layered aggregation to the most complex phytocoenosis" (Hiscock & Connor, 1991).

Bioconcentration
See 'biomagnification'.

Biodegradation
Breakdown or decomposition by bacteria or other biological means.

Biodiversity
"The variability among living organisms from all sources including, inter alia, terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are part; this includes diversity within species, between species and of ecosystems." (UN Convention on Biological Diversity, 1992).

Biogeography
The branch of biology concerned with the geographical distribution of plants and animals, and the factors influencing that distribution.

Biological Diversity
See 'biodiversity'.

Biomagnification
Increasing concentration of a substance in successive trophic levels of a food chain (cf. 'bioaccumulation').

Biomass
The total quantity of living organisms in a given area, expressed in terms of living or dry weight or energy value per unit area.

Biome
A major ecological community, extending over a large area and usually characterized by a dominant vegetation (from Makins, 1991).

Biota
The plant and animal life of a particular site, area, or period.

Biotope
1) The physical 'habitat' with its biological 'community'; a term which refers to the combination of physical environment (habitat) and its distinctive assemblage of conspicuous species. MNCR uses the biotope concept to enable description and comparison. 2) The smallest geographical unit of the biosphere or of a habitat that can be delimited by convenient boundaries and is characterized by its biota (Lincoln et al., 1998).

Biotope Complex
Groups of biotopes with similar overall character (e.g. seagrass beds, rockpools, dense fucoids) (Connor et al., 1997a & b).

Bioturbation
The mixing of a sediment by the burrowing, feeding or other activity of living organisms (Lincoln et al., 1998).

Bipinnaria
Earlier of two larval stages of Asteroid Echinoderms (starfish); characterized by a ciliated band and the presence of arm-like projections (Stachowitsch, 1992).

Biramous
Composed of two distinct branches (Hayward & Ryland, 1995).

Bivalved
Characteristically a shell of two calcareous valves joined by a flexible ligament.

Black Layer
An anoxic layer present below the surface in stable sediment, apparent as a dark layer produced by sulphide salts.

Blue-green Algae
See 'Cyanobacteria'.

Boreal
1) Biogeographical: pertaining to cool or cold temperate regions of the northern hemisphere (Lincoln et al., 1998). 2) Marine zoogeography: Ekman (1953) states that the centre of the boreal region lies in the North Sea. It is bounded by the subarctic transitional zone to the north between Shetland, the Faeroe Islands and Iceland and in the south-west of Britain by a transitional zone with the Mediterranean-Atlantic lusitanian region.

Boring
Makes an excavation (through physical or chemical action) in which to live.

Boulder
An unattached rock, defined in three categories based on Wentworth (1922): very large (> 1024 mm); large (512-1024 mm); small (256-512 mm) (from Hiscock, 1990).

Boulder Clay
See 'till'.

Brachiolaria
The latter of the two larval stages (bipinnaria and brachiolaria) of Asteroid Echinoderms (starfish); characterised by the development of three adhesive arms (brachiolar arms) around a sucker-like structure (Stachowitsch, 1992).

Brackish
Referring to mixtures of fresh and seawater. Usually regarded as between 0.5 ‰ and 30 ‰ salinity (q.v.) (based on McLusky, 1993).

Bract
A modified leaf at the base of a flower stalk (oED, 2008).

Bracts
Plural of 'bract'.

Bristleworm
Literally 'worms with bristles'. Refers to members of the group Polychaeta, which means 'many bristled'.

Bristleworms
Plural of 'bristleworm'.

Brittlestar
The common name for members of the group Ophiuroidea. Brittlestars are related to starfish but recognized by their long, thin, extremely long and articulate arms, which (as the name suggests) break very easily.

Brittlestars
Plural of 'brittlestar'.

Brooding
The incubation of eggs either inside or outside the body. Eggs may be brooded to a variety of developmental stages. Males or females may be responsible for brooding (adapted from Ruppert & Barnes, 1994).

Bryozoa
The Phylum Bryozoa is characterized by sessile colonies made up of many small individuals ca 0.5 mm long called zooids. Each zooid is surrounded by a protective case, which is oval, box-like or tubular in shape. Each zooid bears a bell of ciliated tentacles called the lophophore, which is retracted if disturbed. Colonies have a wide variety of forms, including encrusting sheets or mats, soft fleshy lobes, erect twiggy growths, or bushy tufts (adapted from Ruppert & Barnes (1996) and Hayward et al. (1996)).

Bryozoan
Belonging to the Phylum Bryozoa.

Bryozoans
Plural of 'bryozoan'

Budding
A form of asexual multiplication in which a new individual begins life as an outgrowth from the body of the parent. It may then separate to lead an independent existence or remain connected or otherwise associated to form a colonial organism (Barnes et al., 1993).

Bullate
Balloon or sac-like (Prescott, 1969).

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Glossary references