tration of total phosphorus in the water column at the 20-fathom line 

 (Station 6) was only 0.28 ug-at/L (see table h) . Thus, this upwelling did 

 not produce very high concentrations of phosphorus in the coastal waters. 



In November with slightly colder weather and drop in surface tempera- 

 ture, convection extended to 5>0 meters at Station 8. The normally low con- 

 cent-rations of phosphorus in the upper layers occurred at the offshore sta- 

 tions to a depth of about 80 meters as in October. There was only a slight 

 indication of upward movement of water at Station 7. 



In December with a marked drop in surface temperature, convection 

 extended to 75 meters below which there \-ias a thermocline at Station 8. 

 There was no indication of upwelling at this time. The total phosphor.; 

 content In the upper layers was low from Station 5 outward and to a dep^n 

 of 80 meters. 



From January through April 195>0 no observations were made at Station 8 

 but Station 7 was occupied in all but one of these months. In January the 

 surface temperature was unchanged over December and the wind-stirrea layer 

 extended to J>0 meters at Station 7. However, the bottom temperature was 

 slightly lower than in December indicating a movement of water to this point 

 from another area. 



In winter the inshore waters are colder than the offshore so that 

 from a consideration of temperature alone one cannot arrive at the or.i in 

 of the colder water at the bottom at Station 7. Either upwelling f i . . 

 offshore or a transport from inshore would lower the bottom temperatjit 

 there. However, the inshore waters are less saline and an examination of 

 the salinity records shows that the colder bottom water at Station 7 in 

 January could not have originated inshore. It is interesting to note that 

 the slight upwelling that occurred at this time was not reflected in unusual 

 phosphorus values. 



In February observations did not extend beyond Station 6 but in March 

 all but Station 8 were visited. The thermal structure in March showed a 

 further decrease in temperature at the surface. The bottom temperature 

 was the same as in January but the low values extended up to 30 meters 

 depth. The phosphorus content was very low at all offshore stations. 



In April the surface water had the lowest surface temperature recorded 

 during the first 16 months of the survey, and the wind-stirred layer at 

 Station 7 extended to 5>0 meters. The bottom temperature showed a sharp 

 decrease over the previous month. This time the drop in temperature at 

 the bottom was accompanied by much higher phosphorus content. The phos- 

 phorus found was principally inorganic. In this case the evidence of up- 

 welling was very definite. The temperature, salinity and phosphorus con- 

 tent all indicated a movement of water from a depth of 135 meters offshore. 

 Again it should be noted that this upwelling did not result in high phos- 

 phorus values throughout the water column at the 20-fathom line. The mean 



37 



