40
GORDON A. RlLEY
would expect a tracer experiment to give a low yield, and a high yield
could not be expected unless both naturally occurring and added cation
are present in such low concentxation that a significant fraction of the
total would be adsorbed during the bubbling period.
IV. EXPERIMENTAL STUDIES OF NON-LIVING PARTICULATE
MATTER
A. Adsorption on bubbles
Earlier sections have mentioned the experiment31 finding of Baylor
et al. (1962) and Sutcliffe et al. (1963) that particles can be produced
by adsorption on bubble surfaces, and this process will now be considered in some detail.
Their experimental work was not the first indication that this
process might occur, but for the first time attention was focused on
the possibility that such substances might be biologically important.
Their work had been preceded by about forty years of study of atmospheric sea salt nuclei, a subject that has been ably reviewed by Blanchard (1963) and is mentioned here only as background information.
These nuclei are formed and flung into the air by bubbles breaking at
the surface, and there have been indications that they contain adsorbed
organic materials and organisms as well as sea salts (Woodcock, 1948 ;
Wilson, 1959, and others). Fox and Herzfeld (1955) suggested that
bubbles in the water column could be stabilized by the presence of a
skin of adsorbed organic matter. Moore (1953) found that sea foam
was stabilized by an organic skin of protein.
Baylor et al. (1962) called attention to a peculiar distribution of
phosphate which has often been noted in near surface waters, in which
the concentration in the immediate surface layer is slightly higher than
in the underlying mixed layer. A biological explanation for the observed
negative gradient seems unlikely although not impossible. Baylor
et al. (1962) developed a more sophisticated hypothesis which probably
was suggested by the work on sea salt nuclei and certainly drew
supporting evidence from those studies. They made an experimental
examination of the proposition that phosphate is transported toward
the surface by adsorption on rising bubbles. Their evidence supported
the hypothesis and they further found that organic matter was associated with the adsorption process. The experimental apparatus consisted of a sea water column with a stream of air bubbles entering at
the bottom and a sloping glass surface above the liquid which collected
droplets of aerosol produced by bursting bubbles and allowed them to
accumulate and flow off by gravity into a catchment flask. With this
GORDON A. RlLEY
would expect a tracer experiment to give a low yield, and a high yield
could not be expected unless both naturally occurring and added cation
are present in such low concentxation that a significant fraction of the
total would be adsorbed during the bubbling period.
IV. EXPERIMENTAL STUDIES OF NON-LIVING PARTICULATE
MATTER
A. Adsorption on bubbles
Earlier sections have mentioned the experiment31 finding of Baylor
et al. (1962) and Sutcliffe et al. (1963) that particles can be produced
by adsorption on bubble surfaces, and this process will now be considered in some detail.
Their experimental work was not the first indication that this
process might occur, but for the first time attention was focused on
the possibility that such substances might be biologically important.
Their work had been preceded by about forty years of study of atmospheric sea salt nuclei, a subject that has been ably reviewed by Blanchard (1963) and is mentioned here only as background information.
These nuclei are formed and flung into the air by bubbles breaking at
the surface, and there have been indications that they contain adsorbed
organic materials and organisms as well as sea salts (Woodcock, 1948 ;
Wilson, 1959, and others). Fox and Herzfeld (1955) suggested that
bubbles in the water column could be stabilized by the presence of a
skin of adsorbed organic matter. Moore (1953) found that sea foam
was stabilized by an organic skin of protein.
Baylor et al. (1962) called attention to a peculiar distribution of
phosphate which has often been noted in near surface waters, in which
the concentration in the immediate surface layer is slightly higher than
in the underlying mixed layer. A biological explanation for the observed
negative gradient seems unlikely although not impossible. Baylor
et al. (1962) developed a more sophisticated hypothesis which probably
was suggested by the work on sea salt nuclei and certainly drew
supporting evidence from those studies. They made an experimental
examination of the proposition that phosphate is transported toward
the surface by adsorption on rising bubbles. Their evidence supported
the hypothesis and they further found that organic matter was associated with the adsorption process. The experimental apparatus consisted of a sea water column with a stream of air bubbles entering at
the bottom and a sloping glass surface above the liquid which collected
droplets of aerosol produced by bursting bubbles and allowed them to
accumulate and flow off by gravity into a catchment flask. With this