PARTICULATE ORGANIC MATTER IN S E A WATER
35
gen may be used for co-ordinative purposes. The molecular structure
of urea . . . easily renders itself for such molecular work assignments. . . .
“ Aside of arrangements involving peptides or urea condensates,
oxygen may also be organized in the form of chlathrates. Thus phenols,
quinones, amino acids, amines, sugars, fatty acids, alcohols, and their
respective polymers may coexist within the same polymer by virtue
of their oxygen functions. Further molecular stabilisation can be
achieved by metal ions involving ion co-ordination polyhedra.”
Degens’ paper also contains information on CI3/Cl2 ratios in particulate and dissolved organic matter and in sediments. Evidence is
presented of isotopic fractionation associated with metabolic use of the
organic matter, and these data will be discussed in a later section
which deals with biological transformations.
The use of histochemical stains by Gordon (1970a) has beel mentioned earlier. The mercuric bromphenol blue method (Mazia et al.,
1953) combines directly with free amino groups and by coupling with
mercury to sulphydryl, aromatic and free carboxyl groups. Thus all
classes of proteins are stained, and staining of non-proteins is reported
to be virtually negligible. The Schiff reagent is specific for 1,2-glycol
groups and therefore is a generalized carbohydrate stain. These stsins
have been useful in determining general classes of components in
different kinds of particles. As indicated earlier, flakes and many
smaller particles stsin heavily with the protein stsin as well as with
the Schiff reagent. Amorphous aggregates chiefly take the carbohydrate stain. Any protein staining in the latter, aside from bacteria
and other small inclusions, tends to be a light greenish blue rather than
the intense reds and blues that characterize the staining reactions of
flakes. Thus the protein reaction of aggregates is either quantitatively
small, or, as suggested by Gordon, it may indicate a qualitative difference in the type of protein.
The further question of availability to biological attack was studied
by Gordon (1970a) under simplified laboratory conditions by treating
collections of naturally occurring particulate matter with digestive
enzymes. Duplicate samples were prepared by simultaneous filtration
of measured amounts of a water sample through paired silver filters.
One filter was used for determination of organic carbon content before
treatment. The second filter was treated with a mixture of trypsin,
chymotrypsin and a-amylase. The filters were then washed to remove
hydrolyzed materials and analyzed for carbon, and the difference
between controls and the residue after hydrolysis provided an indication
of the amount of digestible organic matter.
35
gen may be used for co-ordinative purposes. The molecular structure
of urea . . . easily renders itself for such molecular work assignments. . . .
“ Aside of arrangements involving peptides or urea condensates,
oxygen may also be organized in the form of chlathrates. Thus phenols,
quinones, amino acids, amines, sugars, fatty acids, alcohols, and their
respective polymers may coexist within the same polymer by virtue
of their oxygen functions. Further molecular stabilisation can be
achieved by metal ions involving ion co-ordination polyhedra.”
Degens’ paper also contains information on CI3/Cl2 ratios in particulate and dissolved organic matter and in sediments. Evidence is
presented of isotopic fractionation associated with metabolic use of the
organic matter, and these data will be discussed in a later section
which deals with biological transformations.
The use of histochemical stains by Gordon (1970a) has beel mentioned earlier. The mercuric bromphenol blue method (Mazia et al.,
1953) combines directly with free amino groups and by coupling with
mercury to sulphydryl, aromatic and free carboxyl groups. Thus all
classes of proteins are stained, and staining of non-proteins is reported
to be virtually negligible. The Schiff reagent is specific for 1,2-glycol
groups and therefore is a generalized carbohydrate stain. These stsins
have been useful in determining general classes of components in
different kinds of particles. As indicated earlier, flakes and many
smaller particles stsin heavily with the protein stsin as well as with
the Schiff reagent. Amorphous aggregates chiefly take the carbohydrate stain. Any protein staining in the latter, aside from bacteria
and other small inclusions, tends to be a light greenish blue rather than
the intense reds and blues that characterize the staining reactions of
flakes. Thus the protein reaction of aggregates is either quantitatively
small, or, as suggested by Gordon, it may indicate a qualitative difference in the type of protein.
The further question of availability to biological attack was studied
by Gordon (1970a) under simplified laboratory conditions by treating
collections of naturally occurring particulate matter with digestive
enzymes. Duplicate samples were prepared by simultaneous filtration
of measured amounts of a water sample through paired silver filters.
One filter was used for determination of organic carbon content before
treatment. The second filter was treated with a mixture of trypsin,
chymotrypsin and a-amylase. The filters were then washed to remove
hydrolyzed materials and analyzed for carbon, and the difference
between controls and the residue after hydrolysis provided an indication
of the amount of digestible organic matter.