PHYSICAL OCEANOGRAPHIC , BIOLOGICAL, AND CHEMICAL DATA 



SOUTH ATLANTIC COAST OF THE UNITED STATES 



M/V THEODORE N. GILL CRUISE 6 



This is the sixth 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). Biological methods 

 and procedures were the same as those modi- 

 fied on Cruise 3 (Anderson and Gehringer, 

 1957). The basic station plan is shown in 

 figure 1. 



NARRATIVE ACCOUNT OF CRUISE 6 



The Gill departed from Brunswick, 

 Georgia, on April 14, 1954 to commence the 

 southern leg of the cruise. Special sta- 

 tions 5, 6, 7, and 8 were occupied on April 

 15 and 16 and the vessel proceeded to the 

 standard station, arriving on April 17. 

 The vessel remained on standard station for 

 about 40 hours on April 17 to 19, during 

 which time 13 hydrographic casts were com- 

 pleted — one cast going to 2500 meters. 

 Bathythermograph observations, routine 

 meteorological observations, and special 

 plankton tows for deep scattering layer and 

 other studies were also accomplished. 



Damage to the ship's rudder necessi- 

 tated drydocking the vessel at Nassau, 

 B.W.I,, for repairs, and occupation of the 

 regular stations began on April 25. Good 

 weather prevailed, and from April 25 to 28 

 the vessel occupied regular stations 1 

 through 17 aind special station 9. Enroute 

 to station 18 one of the main reduction 

 gears on the main engine was abadly damaged, 

 requiring cancellation of the remainder of 

 the cruise. The Gill arrived back in 

 Brunswick on April 29. The cruise track is 

 shown in figure 2. 



During this short cruise a total of 

 35 hydrographic and 48 bathythermograph 

 casts were made. Oblique plankton tows were 

 taken at each station with the Gulf III 



all-metal planton sampler, the Gulf lA 

 high-speed plankton sampler was towed be- 

 tween stations, and 8 runs of 8 hours each 

 with the continuous plankton sampler. A 

 bottom sample was obtained at most of the 

 stations by means of a modified orange-peel 

 dredge, aind Secchi disc readings were taken 

 whenever conditions permitted. A complete 

 set of water samples for shore analysis on 

 salinity, inorganic phosphate, total phos- 

 phorus, nitrate-nitrite, carbohydrates, and 

 proteins were obtained from all stations 

 and all levels. Oxygen determinations were 

 run aboard vessel for all stations and all 

 levels. Dip-net fishing was conducted dur- 

 ing the day and at night, yielding a con- 

 siderable amount of material. 



Twelve drift bottles were released for 

 the Woods Hole Oceanographic Institution on 

 each of regular stations 3, 4, 5, 10, 11, 

 12, and 13. The bottles used were 8-ounce, 

 clear glass soda bottles approximately 22 

 cm. high and 6 cm. in diameter. To reduce 

 wind drift the bottles were ballasted with 

 clean dry sand, so that they floated ver- 

 tically at or near the surface. Tabulated 

 results are given in table 16. 



Scientific personnel participating in 

 the cruise were: 



I . Southern Leg 



U. S. Fish and Wildlife Service and 



Cooperators : 



William W. Anderson 

 Edward Cohen 

 Vibert L. Strock 



Charles P. Goodwin 



Chief Scientist 



Chemist 



Administrative 



Assistant 

 Chemical Aid 



Navy Hydrographic Office: 

 Melvin Light Senior Oceanographer 

 Richard Williams Oceanographer 

 Charles W. Backus Technician 



Office of Naval Research: 



James Carpenter Chemist (Chesapeake 



Bay Institute) 



