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Glossary: dacriform

February 15th, 2012 — 3:29pm


Glossary: Dahomey Gap

April 16th, 2013 — 1:19pm

Dry corridor of savanna interrupting the West African rain forest and separating it into two parts known as the western Guinea and Central African Congo zones and reaching the Atlantic coast in Togo and Benin. Due to the separation, the resident flora and fauna of the Guinea and Congo zones differs to a significant extent. In terms of […]

Glossary: Daphnia

February 15th, 2012 — 3:29pm

Any representative of the genus Daphnia; small, planktonic crustaceans commonly referred to as ‘water fleas’ and often used as food for ornamental fishes. They’re members of the order Cladocera and reproduce by parthenogenesis.

Glossary: Darwinism

February 15th, 2012 — 3:29pm

Used here on SF in reference to the theory of biological evolution whereby evolution occurs by a process of natural selection thus ensuring survival of the fittest. Includes some theories unconnected with the work of Charles Darwin and has been applied to a range of different philosophies over time, however.

Glossary: decapod

February 15th, 2012 — 3:29pm

Any member of the crustacean order Decapoda, comprising species possessing 5 pairs of jointed, thorassic limbs such as crabs, crayfish, lobsters and shrimp. Also used historically in reference to molluscs of the Cephalopod superorder Decapodiformes, members of which have 8 short limbs plus 2 longer tentacles and include cuttlefish and squid.

Glossary: decomposer

February 15th, 2012 — 3:29pm

Organism feeding on dead or decaying material aiding the natural process of decomposition by breaking down organic substances which subsequently become nutrients.

Glossary: decomposition

February 15th, 2012 — 3:29pm

Natural, ecological process in which organic material is broken down into simpler substances which may then be used by other organisms. Typically biotic and carried out by microbes, worms, and other organisms but can also be abiotic and occur via chemical or physical processes such as oxidation or hydrolysis.

Glossary: decurved

February 15th, 2012 — 3:29pm

Curved downwards. Sometimes used in reference to the lateral line of certain fishes.

Glossary: deep sand bed

February 15th, 2012 — 3:29pm

Method of filtration, mostly used in marine aquaria, whereby the increased depth of the sand substrate facilitates formation of an anaerobic layer where nitrate can be converted into nitrogen gas. Also known as “Jaubert” or “plenum” system and often associated with live sand.

Glossary: defecate

February 15th, 2012 — 3:29pm

To discharge waste from the body via the anus.

Glossary: deionisation

February 23rd, 2012 — 1:29pm

Purification process, often abbrevaited to DI, by which mineral ions are removed from water, usually via ion exchange over a specialised type of resin. The process does not remove non-ionic molecules thus organic cells such as bacteria tend to remain. Often used in conjunction with reverse osmosis to produce more-or-less pure water which normally requires […]

Glossary: deionising unit

February 23rd, 2012 — 1:40pm

Device used to purify water via the process of deionisation. Some units combine both reverse osomosis and deionisation functions.

Glossary: deleterious

February 15th, 2012 — 3:29pm

Having an adverse effect.

Glossary: demersal

February 15th, 2012 — 3:29pm

Living, occurring close to, deposited or sinking onto the bottom of a water body.

Glossary: denitrification

February 15th, 2012 — 3:29pm

Reduction of nitrates to nitrites and ammonia by the breakdown of nitrogenous compounds, or conversion of nitrates into nitrogen-containing gases. Usually carried out by microorganisms.

Glossary: denitrify

February 15th, 2012 — 3:29pm

To reduce nitrates to nitrites and ammonia by the breakdown of nitrogenous compounds, or convert such compounds into nitrogen-containing gases.

Glossary: dentary

February 15th, 2012 — 3:29pm

Anterior, largest and usually only tooth-bearing bone in the mandible.

Glossary: dentate

February 15th, 2012 — 3:29pm

Possessing a serrated or tooth-like edge or margin.

Glossary: denticle

February 15th, 2012 — 3:29pm

A small tooth or toothlike projection, also see dermal denticle.

Glossary: dentigerous

February 15th, 2012 — 3:29pm

Possessing teeth or tooth-like structures.