review of temperature profiles is given in Appendix B. For those areas where nutrient data 

 are lacking, a qualitative estimate of the depth from which artificial pumping will be neces- 

 sary can be made by determining the depth of the bottom of the thermocline. 



The nutrient profiles in Appendix A are divided into four seasons, winter (Jan-Mar), 

 spring (Apr-Jun), summer (Jul-Sep), and fall (Oct-Dec). Table 2 gives the depth range at 

 which a concentration of 30jUg-at/hter NO3 can be expected for the survey area given. In 



the northern sector of the study area (area 12, Fig. 1), surface nutrients are relatively high 

 (1-6 jug-at/liter) in the winter, probably caused by heavy wind mixing and low biological 

 utilization. At 100 meters of depth, nitrate concentration varies from about 12 to 25 Mg-at/ 

 hter, and this increases gradually to 20-35 /ug-at/liter at 300 meters of depth (Fig. A. 3*). 

 During the other seasons, particularly summer, the near-surface nitrate concentrations (up- 

 per 50 meters) are consistently low, being generally below 1 /zg-at/liter. This fact is proba- 

 bly caused by the increased biological productivity found in the mixed surface layer 



In Figures A. 3 to A. 6 the reduced nitrate values (all from a single research cruise) which form an astatistical profile to the 

 left of the main profile appear to be incorrect data and should be ignored. 



Table 2. Depth range at which a concentration of 30 jug-at/liter 

 nitrate can be expected for seasons in the areas surveyed. 







Depth in meters o 



f30/ig-at/liter 





AREA+ 



WINTER 



SPRING 



SUMMER 



FALL 



1-9 



200-300 



200-300 



200-300 



200-300 



10 



N 



250-350 



N 



N 



11 



N 



150-250 



N 



N 



12 



100-200 



100-250 



150-300 



100-250 



13 



*450 



N 



N 



N 



14 



*325 



*500 



*475 



N 



15 



N 



N 



N 



N 



16 



*325-450 



*500 



*475 



N 



17 



100 



N 



N 



N 



18 



N 



*250-300 



N 



N 



19 



100-500 



120->500 



100->500 



>300 



20 



225-350 



200->500 



100->500 



250-350 



* Data sparse 



N Data not available 



+ A reas defined in Fig. 1. 



17 



