dispersion
94
North Atlantic. ].W.S. Marr investigated the biology and distribution of krill
(Euphausia superba), the main food of the whales. Whales were studied
mainly at the whaling station at Grytviken, South Georgia, but also a tagging
program was carried out. The Discovery Reports published the excellent
results of the expeditions, A.C. Hardy's Great Waters (I967) is a well-written
narrative of the first cruise as well as an introduction to the results of the
later cruises.
dispersion (I) (phys.) term used in oceanography in two different ways: in relation to the propagation of waves and in relation to the spreading of a property in different directions. In the first case it is applied to waves of different
frequency starting at the same location, or to the spreading of some local
disturbance that can be considered to be composed of such waves. After
some time the waves with the lower frequency are getting ahead because of
their higher group velocity. The relation between frequency and group velocity, or, more properly, between frequency and wave number (~wave characteristics) is therefore called the dispersion relation. In the second case dispersion
means the spreading of some dissolved or suspended substance because of
a combination of shear and turbulent diffusion at right angles; (2) (biol.) the
distribution pattern in a plant or animal population, ~distribution (1).
displacement experiments experiments in which benthic animals are displaced
from their original habitat to another, in order to study differences in various aspects of the behavior and bioenergetics of these animals in a new versus
a well-known surrounding; also used with birds in studying migration
mechanisms.
displacement volume rough measure of weight, used in plankton field work. The
plankton catch, or a size fraction of it obtained by sieving over a certain mesh
size, is dried on a filter by suction, and put in a known volume of seawater.
The volume increase gives the displacement volume, and, assuming a specific weight of roughly 1, an indication of the fresh weight.
dissolved organic matter ~particulate organic carbon, ~carbon, organic.
distal situated away from; especially from place of attachment; opposite of proximal.
distribution (1) the spatial dispersion or spatial pattern of a population. Three
classes of patterns are often distinguished: regular (there is a fixed distance
between the individuals of a population, which might be a consequence of
competition), random (each individual may occur anywhere in an area with
equal probability; so it is not affected by the occurrence of other individuals) and contagious (individuals occur in clusters or patches; within clusters
their distribution may be regular or random). Most populations in the
94
North Atlantic. ].W.S. Marr investigated the biology and distribution of krill
(Euphausia superba), the main food of the whales. Whales were studied
mainly at the whaling station at Grytviken, South Georgia, but also a tagging
program was carried out. The Discovery Reports published the excellent
results of the expeditions, A.C. Hardy's Great Waters (I967) is a well-written
narrative of the first cruise as well as an introduction to the results of the
later cruises.
dispersion (I) (phys.) term used in oceanography in two different ways: in relation to the propagation of waves and in relation to the spreading of a property in different directions. In the first case it is applied to waves of different
frequency starting at the same location, or to the spreading of some local
disturbance that can be considered to be composed of such waves. After
some time the waves with the lower frequency are getting ahead because of
their higher group velocity. The relation between frequency and group velocity, or, more properly, between frequency and wave number (~wave characteristics) is therefore called the dispersion relation. In the second case dispersion
means the spreading of some dissolved or suspended substance because of
a combination of shear and turbulent diffusion at right angles; (2) (biol.) the
distribution pattern in a plant or animal population, ~distribution (1).
displacement experiments experiments in which benthic animals are displaced
from their original habitat to another, in order to study differences in various aspects of the behavior and bioenergetics of these animals in a new versus
a well-known surrounding; also used with birds in studying migration
mechanisms.
displacement volume rough measure of weight, used in plankton field work. The
plankton catch, or a size fraction of it obtained by sieving over a certain mesh
size, is dried on a filter by suction, and put in a known volume of seawater.
The volume increase gives the displacement volume, and, assuming a specific weight of roughly 1, an indication of the fresh weight.
dissolved organic matter ~particulate organic carbon, ~carbon, organic.
distal situated away from; especially from place of attachment; opposite of proximal.
distribution (1) the spatial dispersion or spatial pattern of a population. Three
classes of patterns are often distinguished: regular (there is a fixed distance
between the individuals of a population, which might be a consequence of
competition), random (each individual may occur anywhere in an area with
equal probability; so it is not affected by the occurrence of other individuals) and contagious (individuals occur in clusters or patches; within clusters
their distribution may be regular or random). Most populations in the