PARTICULATE ORGANIC MATTER I N SEA WATER
7
B. Visual exam,ination of non-living particulate matter
1, General appearance
Fig. 1 shows some common types of particles found in sea water.
The most obvious ones, particularly in the surface layer, are amorphous
masses of material, which will be familiar to everyone who has examined
sea water samples. They have commonly been called detritus, although
identifiable plant or animal remains are only occasionally evident, and
generally as small inclusions rather than constituting the main mass of
material. They appear to be flocculated masses of smaller particles
rather than decomposing bodies and are similar in general appearance
to bacterial slime films that are found growing on submerged surfaces.
Riley (1963) called this material organic aggregates, a term that was
purposely vague as to mode of origin but served to distinguish them
from detritus of identifiable structure.
As seen in this figure the aggregates have been flattened on the slide
and dried, and they appear more consolidated than they really are.
They have been observed in a free floating state in the chamber of an
inverted microscope, where they appear as more or less rounded masses.
They are delicate and tenuous, with internal spaces that harbour a
flora of bacteria, small algae and sometimes protozoa. Pomeroy and
Johannes (1968) have provided an excellent account of this assemblage
of organisms, which they designated as ultraplankton. One suspects
that these microcosms might have quite a different environment from
that of the free water, although the quantity of organisms is not large
enough to suggest a rich supply of nutrients.
The median diameter of these aggregates in most sea water samples
is of the order of 25-50 p. However, there is a wide spectrum of sizes.
Particles of one millimetre or more in diameter are not uncommon,
and on rare occasions sheets of material and slimey strings of the order
of centimetres long have been observed in tide rips.
Gordon (1970a) reported that the aggregates stain heavily with
Schiff reagent and apparently consist mainly of carbohydrate material.
There was virtually no reaction to lipid stains, and the protein reaction
(brom phenol blue reagent) was variable and generally light, except in
associated living organisms.
Fig. 1 also shows some small, semi-transparent flakes, which are
important components of the non-living particulate matter although
much less obvious than the aggregates, Indeed the writer has found no
reference to them in the literature prior to his account (Riley, 1963)
of their natural occurrence in sea water. They may have escaped the
notice of earlier workers or may have been regarded as inorganic
7
B. Visual exam,ination of non-living particulate matter
1, General appearance
Fig. 1 shows some common types of particles found in sea water.
The most obvious ones, particularly in the surface layer, are amorphous
masses of material, which will be familiar to everyone who has examined
sea water samples. They have commonly been called detritus, although
identifiable plant or animal remains are only occasionally evident, and
generally as small inclusions rather than constituting the main mass of
material. They appear to be flocculated masses of smaller particles
rather than decomposing bodies and are similar in general appearance
to bacterial slime films that are found growing on submerged surfaces.
Riley (1963) called this material organic aggregates, a term that was
purposely vague as to mode of origin but served to distinguish them
from detritus of identifiable structure.
As seen in this figure the aggregates have been flattened on the slide
and dried, and they appear more consolidated than they really are.
They have been observed in a free floating state in the chamber of an
inverted microscope, where they appear as more or less rounded masses.
They are delicate and tenuous, with internal spaces that harbour a
flora of bacteria, small algae and sometimes protozoa. Pomeroy and
Johannes (1968) have provided an excellent account of this assemblage
of organisms, which they designated as ultraplankton. One suspects
that these microcosms might have quite a different environment from
that of the free water, although the quantity of organisms is not large
enough to suggest a rich supply of nutrients.
The median diameter of these aggregates in most sea water samples
is of the order of 25-50 p. However, there is a wide spectrum of sizes.
Particles of one millimetre or more in diameter are not uncommon,
and on rare occasions sheets of material and slimey strings of the order
of centimetres long have been observed in tide rips.
Gordon (1970a) reported that the aggregates stain heavily with
Schiff reagent and apparently consist mainly of carbohydrate material.
There was virtually no reaction to lipid stains, and the protein reaction
(brom phenol blue reagent) was variable and generally light, except in
associated living organisms.
Fig. 1 also shows some small, semi-transparent flakes, which are
important components of the non-living particulate matter although
much less obvious than the aggregates, Indeed the writer has found no
reference to them in the literature prior to his account (Riley, 1963)
of their natural occurrence in sea water. They may have escaped the
notice of earlier workers or may have been regarded as inorganic