Figure 3. — Geometric means and (in parentheses) num- 

 bers of observations of zooplankton in milliliters per 

 1,000 m.3 at to 300 m., for each of the areas 1 to 14, 

 In July to December. Day and night data; asterisk indi- 

 cates < 10 observations; for further explanation see text. 



but the order is different. Other values 

 were lower; the lowest was again in area 14 

 (1.5). 



The means for zooplauikton (fig. 3) were high- 

 est in the same areas in which the other two 

 properties were highest (no acceptable data for 

 area 13), but the order is again slightly differ- 

 ent (5 = 1 2 > 9 r= ! 0). Other values were lower; 

 area 2, not area 14, had the smallest mean. 



Figures 4, 5, and 6 summarize the somewhat 

 scantier data, corresponding to those in figures 

 1, 2, and 3, for January to June. Observations 

 are lacking for areas 12, 13, and 14. 



The highest means of chlorophyll a (fig. 4)-- 

 0.28, 0.26, 0.21, and 0.20 mg./m.3 ..were in 

 areas 9, 11, 5, and 3. Upwelling is more pro- 

 nounced in area 3 at this time of year than in 

 July to December. The reason forthe high mean 

 in area 11 is not clear. Useful data are un- 

 available for area 10. Means for other areas 

 declined more or less as before, to a minimum 

 (0.08) in area 1 which is the northern-hemis- 

 phere equivalent of area 14. 



Only four area means of primary productivity 

 were adequately based (fig. 5); the order ofthe 

 areas was 3>'/>l>Z. The mean for area 3 

 (27.8 mg.C/m.3/day) is comparable with that 



Figure 4. — Geometric msans and (in parentheses) num- 

 bers of observations of surface chlorophyll a in milli- 

 grams per cubic meter, for each of the areas 1 to 14, 

 in January to June. Daylight data only; asterisk indi- 

 cates<10 observations; for further explanation see text. 



for the corresponding time-space situation in 

 the southern hemisphere (area 12 in July to 

 December) . 



The order of areas according to zooplankton 

 means (fig, 6) differed substantially from the 

 order according to chlorophyll a. Area 10 had 

 the highest zooplankton mean, but data on 

 chlorophyll a. were not available for that area; 

 adequate zooplankton data were lacking for 

 areas 8 and 1. The main similarities between 

 area means for chlorophyll a and zooplankton 

 were that means for areas 5 ajid 9 were high 

 for both properties, and those for areas 7 and 

 2 low for both. Area 11 had a high chlorophyll 

 a mean but a low one for zooplankton, perhaps 

 because each was based on fewer than 20 ob- 

 servations. 



Apart from these dubious means for area 1 1 

 in January to June, the distribution of means 

 in all the figures (1-6) shows that all three 

 biological properties tended to be highest in 

 situations of coastal upwelling (areas 12, 3, 

 13), offshore equatorial upwelling (9) , and shoal 

 thermoclines (5, 10). Means were lowest in 

 anticyclonic current gyrals where thermo- 

 clines lie deep (14, 1, 2) and intermediate in 

 other situations (means tending to lessen with 



10 



