86
GORDON A. RILEY
table. This is about five times the earlier estimate, which considered
only the observed decrease with depth. These results will be discussed
later in relation t o biological problems in the transition zone. The
values that have been obtained suffer from all of the qualifications that
have been made about the difficulties of relating experimental determinations of sinking rates to the mean rate of sinking of total particulate
carbon. Examination of biological processes within this layer provides
an independent method of calculating carbon consumption which will
be useful for comparative purposes.
(c) The deep ocean. Data presented in earlier sections of this report
indicate that particulate matter in the deep ocean varies regionally in
a manner that is more or less in accord with the productivity of the
surface layer. Thus it would appear that the residence time of particulate organic matter in the deep ocean is short enough for the influence
of surface conditions at the point of formation to be more important
than later horizontal movements of deep water masses. However, the
latter can be important occasionally, as indicated by the fact that Dal
Pont and Newel1 (1963) found maxima and minima associated with
particular water mass characteristics of the south Pacific Ocean. More
commonly vertical variations appear to be of an essentially random
nature, although admittedly the sampling intervals have seldom been
close enough to delineate vertical gradients realistically.
The residence time of much of this material is fairly long, but McGill
(1964) has reported a similar pattern of distribution of organic phosphorus, most of which was present in the dissolved fraction and probably had an even longer residence time. Menzel and Ryther (1968b)
have reported similar regional variations in dissolved organic carbon.
The reason for the slow rate of horizontal dispersal in deep water
lies in the fact that the major transport systems in the deep ocean
are localized, to a degree that was not realized until recent years, and
further mixture of the main mass of deep water is a slow diffusion
process. This was clearly demonstrated in an analysis by Wiist (1955)
of currents in the South Atlantic Ocean based on Meteor data, in
which major north-south currents were concentrated along the eastern
slope of South America. Stommel and Arons (1960) applied the theory
of westward intensification of ocean currents to the deep ocean system,
and their conclusions indicate that this kind of localization is to be
expected in all of the major ocean basins.
Even non-conservative properties of an inorganic nature are somewhat localized in their distribution despite the fact that this distribution is developed during the entire residence time of the water itself.
Riley (1951) examined oxygen distribution in the Atlantic Ocean, based
GORDON A. RILEY
table. This is about five times the earlier estimate, which considered
only the observed decrease with depth. These results will be discussed
later in relation t o biological problems in the transition zone. The
values that have been obtained suffer from all of the qualifications that
have been made about the difficulties of relating experimental determinations of sinking rates to the mean rate of sinking of total particulate
carbon. Examination of biological processes within this layer provides
an independent method of calculating carbon consumption which will
be useful for comparative purposes.
(c) The deep ocean. Data presented in earlier sections of this report
indicate that particulate matter in the deep ocean varies regionally in
a manner that is more or less in accord with the productivity of the
surface layer. Thus it would appear that the residence time of particulate organic matter in the deep ocean is short enough for the influence
of surface conditions at the point of formation to be more important
than later horizontal movements of deep water masses. However, the
latter can be important occasionally, as indicated by the fact that Dal
Pont and Newel1 (1963) found maxima and minima associated with
particular water mass characteristics of the south Pacific Ocean. More
commonly vertical variations appear to be of an essentially random
nature, although admittedly the sampling intervals have seldom been
close enough to delineate vertical gradients realistically.
The residence time of much of this material is fairly long, but McGill
(1964) has reported a similar pattern of distribution of organic phosphorus, most of which was present in the dissolved fraction and probably had an even longer residence time. Menzel and Ryther (1968b)
have reported similar regional variations in dissolved organic carbon.
The reason for the slow rate of horizontal dispersal in deep water
lies in the fact that the major transport systems in the deep ocean
are localized, to a degree that was not realized until recent years, and
further mixture of the main mass of deep water is a slow diffusion
process. This was clearly demonstrated in an analysis by Wiist (1955)
of currents in the South Atlantic Ocean based on Meteor data, in
which major north-south currents were concentrated along the eastern
slope of South America. Stommel and Arons (1960) applied the theory
of westward intensification of ocean currents to the deep ocean system,
and their conclusions indicate that this kind of localization is to be
expected in all of the major ocean basins.
Even non-conservative properties of an inorganic nature are somewhat localized in their distribution despite the fact that this distribution is developed during the entire residence time of the water itself.
Riley (1951) examined oxygen distribution in the Atlantic Ocean, based