the Detroit, Michigan, meetings of the Society 

 of American Bacteriologists in April-May 1957 

 which included information obtained on SCOPE. 



PROCEDURES AT NOON STATIONS 



At approximately local noon of each day, 

 weather permitting, a station was occupied. 

 The general procedure at these stations was 

 as follows: 



1. 900 ft. - BT lowering and general 

 weather observations including barome- 

 ter reading, dry- and wet-bulb air temp- 

 eratures, wind direction and speed, sea 

 and swell observations, and sky condition. 



2. Collection of surface water sample for 

 trailing bottle productivity studies. 



3. Submarine photometer lowering. 



h. 50 m. - Surface, vertical phytoplankton 

 net haul using a i+O-cm. truncate net, 

 with a mesh size of 32^. 



5. Plastic sampler cast to 100 m. - Water 

 samples collected were used in photo- 

 synthetic studies in the shipboard 

 incubator and for the determination 



of chlorophyll "a" concentrations. A 

 small aliquot from each depth was 

 also preserved for subsequent phytoplank- 

 ton analysis. 



6. J-Z sampler cast for bacterial abundance 

 studies. 



7- Nansen bottle cast to approximately 700 m.- 

 The water samples were employed for oxygen, 

 salinity, alkalinity, inorganic phosphorus, 

 pH, and nitrite determinations. 



8. Oblique zooplankton meter-net tow to a 

 depth of approximately 300 m. 



PROCEDURE AT IN SITU PRODUCTIVITY STATIONS 

 (S-9 SERIES, S-20, S-25A, and S-25B) 



Shortly after arrival at these stations a 



surface parachute drogue was released and 

 all subsequent observations were taken along- 

 side the drogue. 



The sampling program was rather variable but 

 consisted of a series of observations, casts, 

 etc., similar to those taken at each noon 

 station. At the S-9 stations several hydro- 

 graphic casts were made with the Nansen 

 bottles very closely spaced. 



The area in which the S-9 station series 

 were located is referred to in this report 

 as "the Dome" or as the thermal anticline 

 region. This is a large region lying off 

 the west coast of Costa Rica characterized by 

 an intense, shallow thermocline. This is 

 an area of high productivity in which the 

 characteristics of upwelled water are absent. 



. PROCEDURES BETWEEN STATIONS 



While underway, between noon stations, 900-ft . 

 BT lowerings were made every three hours 

 (0000, 0300, 0600, 0900, 1200, 1500, l800, 

 and 2100 hours) accompanied by routine 

 weather observations. Surface chlorophyll 

 "a" and inorganic phosphorus determinations 

 were frequently made at 0600 which was also the 

 usual time that the morning trailing bottle 

 productivity experiment began. 



CONTINUOUS OBSERVATIONS 



1. Sea-surface temperature was continuously 

 recorded with a Taylor thermograph. 



2. Incident solar radiation was measured 

 by a 10-junction Eppley pyrheliometer 

 combined with a Speedomax 0-10 mv recorder. 



METHODS 



1. Incident solar radiation: 



A gimbals-mounted Eppley 10-junction 

 pyrheliometer was placed above all super- 

 structure on the afterma6t of the m/v 

 Stranger . The signal from the pyrheliometer 

 was fed into a 0-10 mv Speedomax recorder 

 and was recorded on chart paper travelling at 



