deposit feeders
90
m- 3 , one often uses the so-called density excess, a = p -1000 kg m-3• In older
literature the density anomaly a was used, being a = (p -1) 1000, whereby p
was given in g cm- 3 (cgs units), using the now obsolete equation of state of
seawater according to Knudsen; (2) (bioI.) --7abundance and --7concentration.
deposit feeders animals that are deposit feeding, i.e. feeding on bottom material
with the food value being determined by its organic content. Particles may
be swallowed indiscriminately or sorted for size prior to ingestion.
desalination the process of removing salts from seawater or sea sediment. It is
accomplished by (vacuum) distillation or by high pressure, reverse osmosis
for large-scale production of potable water in oceanic regions with insufficient freshwater resources.
desorption the reverse process of sorption, which itself can be divided into
adsorption and absorption (--7sorption). The speed of desorption is generally
different from that of adsorption (rapid) and absorption (slow). This is
because the adsorption layer will quickly establish a new equilibrium
between the sorbed material on the solid and that in the solution.
Consequently, the release of the absorbed material will determine the desorption speed. For practical use the term half-time of desorption (time of
50 % loss) gives a qualitative indication of the strength of the sorption.
detergents group of alkali-organic compounds with surface-tension reductive
properties, applied for cleaning solid surfaces and cleansing oil-contaminated waters. Detergents with, if possible, nontoxic properties are applied to
solubilize oil slicks and thus increase the bacterial decomposition of the pollutants. Various compounds are poisonous in concentrations of over 0.1 mg
dm- 3 • This is mainly because the change in the surface tension of water
influences the transfer of substances in and out of organisms.
detrital sediments (geol.) sediments consisting of fragments of pre-existing
rocks, produced by weathering and erosion, and in general transported from
another location. --7sediment classification.
detritivores organisms feeding on detritus.
detritus (1) (bioI.) remains (debris) of dead organisms, more or less decomposed
so that the origin cannot easily be traced. It is often mixed with fine inorganic material. If it originates from plants/algae, it is called phytodetritus. Animals,
microbial organisms, or fungi may consume detritus and are then called
detritivores; (2) (geol.) a collective term for loose rock and mineral material
(debris) produced by the desintegration and weathering of rocks and removed
from its site of origin; esp. fragmental material, such as sand, silt, and clay.
90
m- 3 , one often uses the so-called density excess, a = p -1000 kg m-3• In older
literature the density anomaly a was used, being a = (p -1) 1000, whereby p
was given in g cm- 3 (cgs units), using the now obsolete equation of state of
seawater according to Knudsen; (2) (bioI.) --7abundance and --7concentration.
deposit feeders animals that are deposit feeding, i.e. feeding on bottom material
with the food value being determined by its organic content. Particles may
be swallowed indiscriminately or sorted for size prior to ingestion.
desalination the process of removing salts from seawater or sea sediment. It is
accomplished by (vacuum) distillation or by high pressure, reverse osmosis
for large-scale production of potable water in oceanic regions with insufficient freshwater resources.
desorption the reverse process of sorption, which itself can be divided into
adsorption and absorption (--7sorption). The speed of desorption is generally
different from that of adsorption (rapid) and absorption (slow). This is
because the adsorption layer will quickly establish a new equilibrium
between the sorbed material on the solid and that in the solution.
Consequently, the release of the absorbed material will determine the desorption speed. For practical use the term half-time of desorption (time of
50 % loss) gives a qualitative indication of the strength of the sorption.
detergents group of alkali-organic compounds with surface-tension reductive
properties, applied for cleaning solid surfaces and cleansing oil-contaminated waters. Detergents with, if possible, nontoxic properties are applied to
solubilize oil slicks and thus increase the bacterial decomposition of the pollutants. Various compounds are poisonous in concentrations of over 0.1 mg
dm- 3 • This is mainly because the change in the surface tension of water
influences the transfer of substances in and out of organisms.
detrital sediments (geol.) sediments consisting of fragments of pre-existing
rocks, produced by weathering and erosion, and in general transported from
another location. --7sediment classification.
detritivores organisms feeding on detritus.
detritus (1) (bioI.) remains (debris) of dead organisms, more or less decomposed
so that the origin cannot easily be traced. It is often mixed with fine inorganic material. If it originates from plants/algae, it is called phytodetritus. Animals,
microbial organisms, or fungi may consume detritus and are then called
detritivores; (2) (geol.) a collective term for loose rock and mineral material
(debris) produced by the desintegration and weathering of rocks and removed
from its site of origin; esp. fragmental material, such as sand, silt, and clay.