Physical Oceanographic , Biological, and Chemical Data 



South Atlantic Coast of the United States 



M/V Theodore N. Gill Cruise 5 



This is the fifth in a series of 

 reports presenting basic data from cruises 

 of the Theodore N. Gill in waters off the 

 South Atlantic coast of the United States. 



Background of the investigations; 

 objectives; procedures on station; and 

 chemical, biological and oceanographic 

 methods and procedures were presented in 

 the report for Cruise 1 (Anderson, Geh- 

 ringer, and Cohen, 1956). Biological 

 methods and procedures were the same as 

 those used on Cruises 3 and k (Anderson 

 and Gehringer, 1957a and 1957b). The 

 basic station plan is shown in figure 1. 



NARRATIVE ACCOUNT OF CRUISE 5 



The Gill sailed from Brunswick, Georgia 

 on January 20, 195 1 *-, to begin the southern 

 leg of the cruise. Special stations 5, b, 

 and 7 were occupied on January 21 and 22, 

 but heavy seas prevented the taking of spe- 

 cial station 8. The standard station was 

 occupied for a period of about k2 hours 

 from January 23 to 25, during which time 

 Ik hydrographic casts were completed. 

 Routine meteorological observations, bathy- 

 thermograph observations, and special 

 plankton tows for deep scattering layer 

 and other studies were also taken. 



The vessel proceeded to Nassau, B. W. I, 

 and special equipment was installed by 

 Columbia University personnel. On January 

 27-28 a special ambient station was conducted 

 east of Eleuthera Island. Very strong winds 

 caused the work to be terminated and the 

 special equipment was unloaded at Nassau on 

 January 29. 



Occupation of the regular stations 

 began on January 30. Workable weather con- 

 ditions were encountered most of the remain- 

 der of the southern leg, and all but 5 of 

 the regular stations were worked. The 

 vessel returned to Brunswick on February 6 

 for supplies. 



The northern leg of the cruise commenced 

 on February 9 and adverse weather conditions 



plagued most of this part of the cruise-- 

 only a day or day and a half of workable 

 weather being available at a stretch. In 

 spite of this handicap the coverage was as 

 complete as could be expected during win- 

 ter- -9 regular and k special stations were 

 omitted. The vessel occupied the last 

 station on February 23 and arrived back in 

 Brunswick on February 25 to terminate the 

 cruise . The cruise track is shown in 

 figure 2. 



Approximately 3>000 miles were trav- 

 eled in accomplishing this cruise, 83 

 oceanographic stations were occupied (in- 

 cluding regular, special and standard), 

 and a total of 97 bathythermograph casts 

 and 83 Nansen casts (fig. 3) were made. 

 Bottom samples were obtained on many 

 stations (fig. k) , and Secchi disk readings 

 were taken during daylight hours when con- 

 ditions permitted. Oxygen determinations 

 were made aboard vessel for all stations 

 and all levels. Water samples were collect- 

 ed from all stations and levels for shore 

 analysis on salinity, total phosphorus, 

 inorganic phosphate, carbohydrates, pro- 

 teins, and nitrate. An oblique plankton 

 tow was made with the Gulf III all-metal 

 plankton sampler on all but a few of the 

 stations--a standard half -meter silk net 

 was utilized on a few stations where heavy- 

 seas made use of the all-metal sampler 

 impractical. In addition, kk runs with the 

 Gulf IA high-speed sampler between stations, 

 and 31 runs with the continuous plankton 

 sampler were obtained. Dip-net fishing was 

 carried out both during the day and at 

 night under lights whenever possible. Col- 

 lections of material by dip net were not 

 as fruitful as on some previous cruises — 

 this because of rough sea conditions as 

 well as an apparent scarcity of young fish 

 at the surface over much of the area. 



Scientific personnel participating in the 

 cruise were: 



I. Southern Leg 



U. S. Fish and Wildlife Service and 

 Cooperators : 



W. W. Anderson Chief Scientist 



