MarLIN Glossary

Glossary items


Devoid of life.


Opposite the end/side on which the mouth is located (Kozloff, 1996).


Refering to the deepest part of the ocean, below about 2000 m (OED, 2008).


Build up or accumulation of sediment.


Plural of 'acontium'.


Thread-like nematocyst bearing organ attached to lower end of a mesentery or septal filament in the gastrovascular cavity in some Actinaria (Anemones). The acontia my be protruded through perforations (cinclides) of the body wall (adapted from Manuel, 1988 and Stachowitsch, 1992).

adambulacral plates

Of Echinodermata (echinoderms); a series of calcareous plates on either side of the ambulacral furrow (Southward & Campbell, 2006).

adambulacral spines

Of Echinodermata (echinoderms); spines on adambulacral plates (Southward & Campbell, 2006).


Organisms (usually referring to of the same species) living closely together, but not physically connected (cf. 'colony').

algal gravel

See 'maerl'.

algal mat

A dense mass of green or other algae (e.g. Enteromorpha spp., Ulva spp.) which blankets the substratum in a littoral or shallow-water environment, often in areas of freshwater influence or where eutrophication occurs.

alien species

A non-established introduced species (q.v.), which is incapable of establishing self-sustaining or self-propagating populations in the new area without human interference (cf. 'introduced species'; 'non-native').


Exogenous, originating outside and transported into a given system or area (Lincoln et al., 1998).


Plural of 'ambulacrum'.


Adjective of 'ambulacrum'.

ambulacral furrow

Of Echinodermata (echinoderms); groove or furrow in the oral side of the arm holding the tube feet (Southward & Campbell, 2006).

ambulacral furrows

Plural of 'ambulacral furrow'.


Of Echinodermata (echinoderms); radially arranged regions of the body of Echinoderms that bear the tube feet (Southward & Campbell, 2006).

amphidromic point

The central point of a cyclonic tidal system, at which the vertical astronomical tidal range is nil, or very small, increasing progressively with increasing distance from this central point (from Ministry of Defence, 1987.)


A crustacean belonging the Order Amphipoda (cf. Amphipoda).


An group of crustaceans recognized by their laterally compressed bodies, lack of a carapace, and numerous, differently modified legs (Hayward et al., 1996).


Of fish - upward-running: spending part of their life in the sea and migrating up rivers in order to breed (e.g. salmon) (cf. 'catadromous').


An environment in which the partial pressure of oxygen is significantly below normal atmospheric levels; deoxygenated (Lincoln et al., 1998).


Relating to or near the anus, or the posterior opening of the alimentary canal (Abercrombie et al., 1973).


Reproductive strategy in which individuals are either strictly males or hermaphrodites.


Having flagellate gametes of different size, shape or behaviour (from Bold, 1977 and Lincoln et al., 1998).


Where the external surface is divided into a chain of rings or 'annuli' by furrows giving the appearance of segments (Barnes et al., 1993).


Devoid of oxygen.


Second and typically longer of a pair of antennae, sensory appendages originating on the head of Crustacea.


First and typically shorter of a pair of antennae, sensory appendages originating on the head of Crustacea.


Produced by human activity.


The cultivation of aquatic organisms by human effort for commercial purposes. For the cultivation of marine organisms in seawater, the term 'mariculture' is also used. (Based on Baretta-Bekker et al., 1992).


Having the shape or characteristics of a tree.


Having the shape or characteristics of a tree.


Referring to a biogeographical region centred north of the British Isles and influencing the extreme north of the British Isles.


Marked by or consisting of areolae, small areas, islands or circular spots of tissue. Used to describe the thallus of lichens (adapted from Dobson, 2000).

Aristotle's lantern

The mouthparts of sea urchins. A complex chewing apparatus made up of five calcareous teeth or jaws used at scraping food from the substratum.


Jointed, arthrous (Holmes, 1979).


Sac-like hydrostatic organ in ascophoran Cheilostomatida Bryozoa. Also termed the 'compensation sac' (Hayward & Ryland, 1998).


A generic term used chiefly by some British marine ecologists which does not assume interdependence within a community or association, but appears to have the same broad definition as 'community' (based on Hiscock & Connor, 1991).


1) The evaluation of marine natural heritage importance through an orderly process of gathering information about biotopes and species in an area and comparing their attributes by a standard protocol (as in 'conservation assessment'). 2) The evaluation of the likely impact of a development on the environment (as in 'Environmental Impact Assessment').


A term used by botanists to refer to an assemblage of plants with a definite floristic composition, considered by many workers to be synonymous or very similar to the zoological concept of 'community' (from Hiscock & Connor, 1991).

astronomical tide

The periodic rise and fall of the ocean water masses, produced by gravitational effects of the moon and sun on the earth (from Lincoln & Boxshall 1987). Cf. lunar tide


A characteristic of a habitat, biotope, community or population of a species which most economically provides an indication of the condition of the interest feature to which it applies (CSMR).


The ecology of individual organisms or species (Lincoln et al., 1998) (cf. 'synecology').


Produced within the given habitat, community or system (Lincoln et al., 1998), often used to describe organic matter produced in situ (cf. 'endogenous', 'allochthonous').


Self-feeding, producing organic matter through photosynthesis (Prescott, 1969).


Feeding zooid in Bryozoa (cf. 'zooid') (Hayward & Ryland, 1998).


Plural of 'avicularium'.


Specialized zooid in Cheilostomatida Bryozoa, with reduced polypide but strong muscles which operate a mandible-like operculum (Hayward & Ryland, 1998).


Devoid of animal life.


An organism without 'zooxanthellae'