PARTICULATE ORGANIC MATTER IN SEA WATER
9
inclusions. I n fact the writer did not include them in routine counts
until it became apparent that they were visually indistinguishable
from experimentally produced organic particles of the type which
Baylor and Sutcliffe (1963) demonstrated to be adequate food for the
growth of Artemia.
Later Gordon (1970a) showed that they react intensely to protein
and carbohydrate stains. His counts of stained material were invariably
larger than those of unstained aliquots. Some of this material is so
nearly transparent that it eludes detection except by staining treatment.
The median size of the flakes is about 25 p in their longest dimension.
The size range is not large, and few of them are more than 50 p. Gordon
categorized two types of larger particles that are found occasionally,
which exhibited the same kind of staining reactions as flakes but otherwise were somewhat different in appearance. One type was long and
narrow; the other resembled a clump of smaller flakes. It is still an
open question as to whether they are different in any really significant
way and whether the clumping is a natural phenomenon or an artifact
of preparation.
Aside from the aggregates and flakes, most samples contain a number of minor organic components such as more or less recognizable
remains of phytoplankton and zooplankton, fibres, occasional faecal
pellets, and starch grains. Bursa (1968) has described the starch grains
that he has found in sea water and plankton samples, sometimes in
great abundance at Arctic stations, with which he was particularly
concerned. Similar material was found at inshore locations in tropical
and subtropical waters. The writer has occasionally seen identifiable
starch grains in offshore water although never in abundance. However,
some of Bursa’s photographs of semi-hydrolyzed grains suggest that
there might be difficulty in distinguishing between starch and flakes in
some cases unless specific staining procedures are used. The problem
of identifying non-living particles is certainly not easy, and further
study is in order.
Small particles of the order of 5 p down t o the limits of visibility
are numerically more abundant than the larger particles. Many of
them show organic staining reactions, but visual examination gives
little clue as to their origin. Traditionally they have been regarded as
breakdown products of larger remains. However, Sheldon et al. (1967)
documented spontaneous formation by aggregation of smaller entities,
and Chave (1965) has detected coatings of adsorbed organic matter on
particles of calcium carbonate. Conceivably other minerals could be
similarly coated. Thus the small particles probably are of diverse
9
inclusions. I n fact the writer did not include them in routine counts
until it became apparent that they were visually indistinguishable
from experimentally produced organic particles of the type which
Baylor and Sutcliffe (1963) demonstrated to be adequate food for the
growth of Artemia.
Later Gordon (1970a) showed that they react intensely to protein
and carbohydrate stains. His counts of stained material were invariably
larger than those of unstained aliquots. Some of this material is so
nearly transparent that it eludes detection except by staining treatment.
The median size of the flakes is about 25 p in their longest dimension.
The size range is not large, and few of them are more than 50 p. Gordon
categorized two types of larger particles that are found occasionally,
which exhibited the same kind of staining reactions as flakes but otherwise were somewhat different in appearance. One type was long and
narrow; the other resembled a clump of smaller flakes. It is still an
open question as to whether they are different in any really significant
way and whether the clumping is a natural phenomenon or an artifact
of preparation.
Aside from the aggregates and flakes, most samples contain a number of minor organic components such as more or less recognizable
remains of phytoplankton and zooplankton, fibres, occasional faecal
pellets, and starch grains. Bursa (1968) has described the starch grains
that he has found in sea water and plankton samples, sometimes in
great abundance at Arctic stations, with which he was particularly
concerned. Similar material was found at inshore locations in tropical
and subtropical waters. The writer has occasionally seen identifiable
starch grains in offshore water although never in abundance. However,
some of Bursa’s photographs of semi-hydrolyzed grains suggest that
there might be difficulty in distinguishing between starch and flakes in
some cases unless specific staining procedures are used. The problem
of identifying non-living particles is certainly not easy, and further
study is in order.
Small particles of the order of 5 p down t o the limits of visibility
are numerically more abundant than the larger particles. Many of
them show organic staining reactions, but visual examination gives
little clue as to their origin. Traditionally they have been regarded as
breakdown products of larger remains. However, Sheldon et al. (1967)
documented spontaneous formation by aggregation of smaller entities,
and Chave (1965) has detected coatings of adsorbed organic matter on
particles of calcium carbonate. Conceivably other minerals could be
similarly coated. Thus the small particles probably are of diverse