PARTICULATE ORGANIC MATTER I N SEA WATER
17
There was a sharp increase in carbon t o a maximum of 150 pg/litre at
the level of the intermediate salinity minimum, which presumably
represents the core of the Antarctic Intermediate Water. Lower
values of 36-82 pg/litre were found between about 1 400 and 3 300 in.
The deep salinity maximum lies within this zone. This salinity maximum is believed t o be due t o the influence of North Atlantic Deep
Water which leaves the Atlantic Ocean around the southern tip of
Africa and traverses the southern part of the Indian and Pacific
Oceans as a northern component of the general Antarctic circumpolar
drift. Values at 3 763 and 4 210 m were respectively 207 and 106 pg
C/litre. Probably this is primarily Antarctic Circumpolar water.
Holm-Hansen et nl. (1966) described a station off California, which
also showed considerable vertical variation. There was a general increase at the depth of the oxygen minimum layer with a maximum
concentration of 100 pg C/litre. Most of the deepwater values were
between 20 and 6 0 p g C/litre, but here too there was evidence of
distinct layering. This station was taken in one of the deep basins off
the California coast, and in several respects it was not quite typical
of open oceanic conditions. There is a possibility that the unusual
amount of variability observed here was associated with peculiarities
of basin circulation. However, in the present state of our ignorance
an equal possibility exists that closer sampling intervals at oceanic
stations would reveal a similar degree of layering.
Hobson ( 1 967) reported the results of six cruises t o an area in the
North Pacific between 45" and 48"N and 135-140"W. There was a
large range in deep water values, from 8-110 pg C/litre, with considerable layering and with systematic seasonal variations, which appeared
to represent a movement through the profile of discrete parcels of
water with relatively high concentrations of 30-1 10 pg C/litre. Computed currents were more or less in accord with the concept of seasonal
transport of water masses through the area.
Menzel (1964) published figures for two stations in the Arabian Sea.
Individual analyses in waters of 200 m or more ranged from 17-80 pg
C/litre, and the average values for the two stations were 32 and 35 pg.
Menzel's work was primarily concerned with dissolved organic carbon
in the western Indian Ocean, and his data on particulate matter were
incidentaI t o the main purpose. Later work by Szekielda (1967) provided more extensive coverage of this region, including transects off
the Somali coast and one across the Gulf of Aden. I n general his values
were higher than those reported by Menzel. The lowest ones obtained
were of the order of 60 pg C/litre, and they ranged upward t o about
140pg in the core of the Red Sea outflow and in near-bottom waters
17
There was a sharp increase in carbon t o a maximum of 150 pg/litre at
the level of the intermediate salinity minimum, which presumably
represents the core of the Antarctic Intermediate Water. Lower
values of 36-82 pg/litre were found between about 1 400 and 3 300 in.
The deep salinity maximum lies within this zone. This salinity maximum is believed t o be due t o the influence of North Atlantic Deep
Water which leaves the Atlantic Ocean around the southern tip of
Africa and traverses the southern part of the Indian and Pacific
Oceans as a northern component of the general Antarctic circumpolar
drift. Values at 3 763 and 4 210 m were respectively 207 and 106 pg
C/litre. Probably this is primarily Antarctic Circumpolar water.
Holm-Hansen et nl. (1966) described a station off California, which
also showed considerable vertical variation. There was a general increase at the depth of the oxygen minimum layer with a maximum
concentration of 100 pg C/litre. Most of the deepwater values were
between 20 and 6 0 p g C/litre, but here too there was evidence of
distinct layering. This station was taken in one of the deep basins off
the California coast, and in several respects it was not quite typical
of open oceanic conditions. There is a possibility that the unusual
amount of variability observed here was associated with peculiarities
of basin circulation. However, in the present state of our ignorance
an equal possibility exists that closer sampling intervals at oceanic
stations would reveal a similar degree of layering.
Hobson ( 1 967) reported the results of six cruises t o an area in the
North Pacific between 45" and 48"N and 135-140"W. There was a
large range in deep water values, from 8-110 pg C/litre, with considerable layering and with systematic seasonal variations, which appeared
to represent a movement through the profile of discrete parcels of
water with relatively high concentrations of 30-1 10 pg C/litre. Computed currents were more or less in accord with the concept of seasonal
transport of water masses through the area.
Menzel (1964) published figures for two stations in the Arabian Sea.
Individual analyses in waters of 200 m or more ranged from 17-80 pg
C/litre, and the average values for the two stations were 32 and 35 pg.
Menzel's work was primarily concerned with dissolved organic carbon
in the western Indian Ocean, and his data on particulate matter were
incidentaI t o the main purpose. Later work by Szekielda (1967) provided more extensive coverage of this region, including transects off
the Somali coast and one across the Gulf of Aden. I n general his values
were higher than those reported by Menzel. The lowest ones obtained
were of the order of 60 pg C/litre, and they ranged upward t o about
140pg in the core of the Red Sea outflow and in near-bottom waters