FISHERY BULLETIN: VOL. 70, NO. 4 



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PHAEO - PIGMENT / CHLOROPHYLL 



1.4 



Figure 5. — Median ammonium concentrations and phaeo- 

 pigment/chlorophyll ratios for Period A, Period B, and 

 Period C. 



to a lesser degree for ammonium but was not 

 the case for urea. 



Table 2 shows that the slopes for nitrate, ni- 

 trite, and ammonium regression equations con- 

 trasting the two stations sampled on any one day 

 are positive and are significantly different from 

 zero for each period. This implies that the val- 

 ues observed at each depth at one station on a 

 particular day are positively correlated with 

 those at corresponding depths at the other sta- 

 tion. This resulted because the nitrate and ni- 

 trite profiles were nearly identical for the two 

 stations on a single day and the ammonium pro- 

 files generally resembled each other. The re- 

 gression slopes for the nitrate and nitrite data 

 were all similar to 1.0, but the ammonium and 

 urea slopes were occasionally far from unity. 

 The regression slopes for the urea data were not 

 significantly different from zero for either Pe- 



riod B or Period C. This analysis indicates that 

 the patch structure of urea distribution is prob- 

 ably of a smaller horizontal scale than that of 

 nitrate, nitrite, or ammonium. In comparing 

 a particular depth at one station with the cor- 

 responding depth at another station, the two 

 urea values are less likely to be similar than the 

 ammonium values and considerably less than the 

 nitrate or nitrite values. 



The similarity of median values for the sta- 

 tion pairs sampled on the same day (Table 3) 

 suggests, on the other hand, a homogenous dis- 

 tribution for each nutrient over the sampling 

 area; however, the stations showed markedly 

 more resemblance in nitrate, nitrite, and ammo- 

 nium than in urea. Comparisons also showed 

 that within each period the median at Stations I 

 and III were not different. This further sup- 

 ports the hypothesis of a smaller patch structure 

 for urea since there was no persistent difference 

 between stations with respect to urea, even 

 though on any one day the stations may have 

 differed significantly. 



The three periods were based on the timing 



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PHAEO-PIGMENT / CHLOROPHYLL 



1,4 



Figure 6. — Median urea concentrations and phaeo-pig- 

 ment/chlorophyll ratios for Period A, Period B, and 

 Period C. 



1270 



