Physical Oceanographic , Biological, and Chemical Data 



South Atlantic Coast of the United States 



M/V Theodore N. Gill Cruise k 



This is the fourth 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, Gehrin- 

 ger, and Cohen, 1956). Modifications to 

 the biological methods and procedures were 

 presented in the report for Cruise 3 (Ander- 

 son and Gehringer, 1957) --operations on 

 Cruise h were the same as for Cruise 3- 

 The basic station plan is shown in figure 1. 



NARRATIVE ACCOUNT OF CRUISE k 



The vessel departed from Brunswick, 

 Georgia, on October 1, 1953 > on the southern 

 leg of the cruise. Very rough seas pre- 

 vented occupation of the series of special 

 stations 5 through 8 and the standard sta- 

 tion. 



On October 5 special equipment was 

 installed on the Gill in Nassau, B.W.I. , 

 and on October 7 and 8 special research in 

 the "Tongue of the Ocean" south of New 

 Providence Island was carried out by scien- 

 tists from the Columbia University Physics 

 Department. Sonic soundings were made to 

 and from Nassau and between stations. 

 Hurricane warnings caused a reduction in 

 the number of stations planned for the spe- 

 cial work. 



Good weather prevailed after regular 

 station work was begun and all but one of 

 the 3^ southern leg stations were occupied. 

 The Gill returned to Brunswick on October 

 17, terminating the southern leg of the 

 cruise. 



Departure from Brunswick to begin the 

 northern leg of the cruise was made on 

 October 21. This leg was characterized by 

 high winds and heavy seas, and the vessel 

 was forced into Charleston, S. C, and 

 Morehead City, N. C, a total of 3 times. 

 Loss of the ship's rudder off Cape Fear, 



N. C, caused a week's delay. Despite the 

 adverse weather conditions and breakdown, 

 only 6 regular stations and the k special 

 stations were omitted. The Gill returned 

 to Brunswick on November Ik, terminating 

 the cruise. The cruise track is shown in 

 figure 2. 



Hydrographic casts were accomplished 

 on each station together with meteorologi- 

 cal observations. Only a few bathythermo- 

 graph lowerings were made due to breakdown 

 of the winch and to loss of instruments. 

 Oxygen determinations were run aboard ves- 

 sel for all stations and all levels (fig. 

 3)' Water samples for analysis ashore on 

 salinity were obtained for all stations, 

 and on every other station for inorganic 

 phosphate, carbohydrates, and proteins (a 

 backlog of samples caused by absence of a 

 chemist for several months resulted in lack 

 of enough containers to sample completely) . 

 An oblique plankton tow with the Gulf III 

 all-metal plankton sampler was made on 68 

 of the regular stations, and an oblique tow 

 with the half -meter silk net was taken on 

 5 stations. The Gulf IA high-speed sampler 

 and the continuous plankton sampler were 

 operated over much of the cruise route. 

 Trolling with feather and bone jigs between 

 stations for larger fish (fig. k) , and dip- 

 netting, both during the day and at night 

 under spotlights, were conducted. Bottom 

 sediment samples were obtained on many of 

 the stations with the modified orange-peel 

 dredge. Secchi disc readings were taken on 

 3tation during daylight hours. 



Scientific personnel participating in the 

 cruise were: 



I. Southern Leg 



U. S. Fish and Wildlife Service and 

 Cooperators: 



Jack W. Gehringer Chief Scientist 

 Frank T. Khapp Biologist (Georgia 



Game and Fish Comm. ) 

 J. E. Moore Chemist (Georgia 



Game and Fish Comm. ) 

 Clyde C. Bryant Chemical Aid 

 Charles P. Goodwin Chemical Aid 



