Nutrient Analysis 



At the beginning of the cruise, phosphates, 

 nitrates, and silicates were determined aboard 

 ship using the methods described by Strickland 

 and Parsons (1965). Unfortunately, the spec- 

 trophotometer purchased for the ship became 

 inoperative. The spare instrument from the 

 U.S. Coast Guard Oceanographic Unit was also 

 inoperative owing to damage in shipment. 

 Consequently, the samples were frozen for the 

 remainder of the cruise. Frozen samples were 

 returned to the U.S. Coast Guard Oceano- 

 graphic Unit to determine nitrates, nitrites, 

 silicates, phosphates and ammonia. Some of 

 these samples were ruined by freezer malfunc- 

 tion. Consequently, nitrite determinations from 

 stations 030 to 060 and all nutrient data from 

 stations 043 to 060 were invalid. 



Oxygen 



The amount of dissolved oxygen was deter- 

 mined on all samples using a modified (Strick- 

 land and Parsons, 1965) Winkler method. 



Salinity-Temperuture-Depth System (STD) 



The STD was used at the major stations to 

 obtain a continuous profile of temperature and 

 salinity with depth. When deep STD and Nan- 

 sen casts were taken at the same station, the 

 STD cast was usually terminated at about 2000 

 meters depth. This saved time, yet allowed 

 all the important inflection points (except any 

 that occurred very near the bottom) to be 

 observed. A single Nansen bottle was attached 

 to the STD cable just above the underwater 

 unit so that quality control and calibration of 

 the STD data could be accomplished. 



Bottom Cores 



Bottom cores were obtained by using two 

 gravity corers attached to a bridle to permit 

 simultaneous lowering. The arrangement 

 worked quite well. Core lengths averaged about 

 three feet. The cores were retained in the plas- 

 tic core liners and were then coated with wax 

 and stored upright in cold storage. 



Bottom Photography 



A Thorndike (1959) type bottom contact 

 camera was used for bottom photographs. 

 Both Plus-X black and white film and high 

 speed color film were used. The camera system 

 was set so that a photograph was taken with 

 the camera lens about three feet above the bot- 

 tom and at an angle of approximately sixty 

 degrees from the vertical. The strobe light was 

 attached beneath the camera and oriented at 

 about the same angle as the camera. This re- 

 sulted in a close-up of the bottom at an oblique 

 angle which gave somewhat of a three-dimen- 

 sional effect because of shadows. The ship's 

 photographer was able to develop both types 

 of film. The results of the bottom photography 

 are presented in a paper by Hollister and Elder 

 (1969). 



Vertical Plankton Tow 



Two 1/4 meter nets were used simultaneously 

 to obtain plankton samples. One of the nets 

 had a mesh size suitable for zooplankton and 

 the other a mesh size suitable for phytoplank- 

 ton. These were lowered to 200 meters. Lower- 

 ing and retrieving rates were approximately 

 20 meters per minute. 



Productivity and Chlorophyll 



Although chlorophyll content was not mea- 

 sured continuously, as was originally planned, 

 it was measured frequently by obtaining sam- 

 ples With a bucket. Samples at depths gov- 

 erned by various levels of incident radiation 

 were obtained using Van Dorn bottles. Because 

 of loss of bottles through damage, two casts 

 were required to obtain six near-surface sam- 

 ples. These were obtained at local apparent 

 noon at depths of 100, 60, 23, 11 and 2 percent 

 of incident light penetration plus two other 

 depths selected for other reasons. A secchi disc 

 was used to determine light extinction. A sub- 

 marine photometer was also used from time 

 to time as a further measurement of light pene- 

 tration. 



Results of Analysis 



Sixty-one oceanographic stations were taken 

 by USCGC GLACIER during IWSOE '68. Four 

 sections through these stations were selected 

 for analysis (fig. 3). Vertical distribution of 



sigma-t, temperature, salinity and oxygen con- 

 tent were determined for these sections and 

 are reproduced in Figures 4-19. 



Analysis of the data indicate that two main 



