Arabian Sea Upwelling
49
b) Biological Events
The distributions of dissolved inorganic P0 4 3 - -P, chlorophyll a and zooplankton
biomass on the Somali coast are shown in Fig. 12 in a manner similar to the data from
the SE Arabian coast. The lower diagramm (section III) (Stns. 5533 - 42) lay in the more
.li'I
m
~
1.0
-'",_ ..
1.5
1.0
;'~
" . .-.. -
0.5~
O~----~----~----~~
o
100
200
MILES OffSHOR.E
-
PIOSPHATE Img-atm-31
---- ZOOPLANKTON Imt m-31
_ .. · ...... CHLOROPHYllll. Imgm -31
Fig. 12. Data on the average concentration of dissolved inorganic phosphate, chlorophyll a and
zooplankton off the Somali coast in 1964. The observations are plotted in a manner similar to Fig. 9.
Positions of the sections are described in the text
southerly part of the Somali Current, section IV (Stns. 5542 - 53) lay at the point where
the current leaves the coast (in about 08
0
30' N, with the section more or less normal to
the current) and sections V (Stns. 5554- 60) and VI (Stns. 5565 - 61) progressively
farther north across the cold water region and the area where it meets the warmer Gulf
of Aden water. In the southerly part of the Somali Current all values were consistently
low, but at the point of its departure from the coast (the inshore end of section IV) a
marked increase in the levels of POl- -P and chlorophyll a was recorded. Section V