138
S. Z. EL·SAYED and H. R. JITIS:
o C E A N
1' •••••• '. 1 111111
}iii:::::
o
::::10>:::
{[ ::::0:::
· ~~~t~~~
ill
45'
Fig. 7. Distribution of primary production (gC m- 2 day-I) in the Indian Ocean based mainly on
"Eltanin" cruise 46 and" Anton Bruun" cruises 2, 3, 4 A, 5, 6, 7, and 8 (RYTHER et ai., 1966)
vessels are taken into consideration. For instance, the "Eltanin" primary productivity
data are based on the in situ experiments, while those of the "Anton Bruun" are the
results from incubation on board ship. The simulated in situ I4C uptake measurements
carried out during the "Eltanin" cruise gave consistently higher figures than those of the
in situ I4C uptake assimilation. Despite the significant differences between the productivity
data in both regions, it is surprising that our average primary production value (0.13 gC
m -2 day-I) is only slightly less than half the mean rate of production for the western
Indian Ocean (0.35 gC m- 2 day-I) reported by RYTHER et al. (1966).