winches aboard the R/V ALBATROSS IV, the 

 rosette multi-sampler was clamped to the protec- 

 tive cage of the STD "fish", rather than directly 

 to the STD cable immediately above the "fish". 

 This arrangement allowed a maximum of 9 

 sample bottles to be used. Since this device 

 could be triggered to collect water samples for 

 chemical analyses from selected depths, tlie need 

 for separate Nansen casts was eliminated. 



Nutrient Analyses 



Water samples collected during ICNAF Cruise 

 69-1 for nutrient determination were frozen and 

 stored aboard ship for later analyses ashore. The 

 samples were analyzed at the U.S. Coast Guard 

 Academy, using a Beckman DU-2 si^ectropho- 

 tometer. Inorganic phosphorous was determined 

 by the method of Murphy and Riley (1962), 

 using an ascorbic acid single-solution reagent. 

 Inorganic nitrate-nitrogen was analyzed by re- 

 duction with cadmium-mercury amalgam and the 

 development of an azo dye complex with sulfa- 

 nilamide (Morris and Riley, 1963). Silicate- 

 silicon was determined by the method of Grass- 

 hoff (1965). 



The nutrient data are included in the oceano- 

 graphic data listings in appendix A. 



Shipboard Operational Summary 



DATA PRESENTATION 



Data listings for ICNAF cruises 68-1 and 

 69-1 are contained in Tables I and II of Ap- 

 pendix A. Surface isotherms, isohalines and 

 isopycnals are presented in figures 9 through 14. 

 Profiles of temperature, salinity, sigma-t. oxygen, 

 and chlorophyll are depicted in figures 15 through 

 79. 



RESULTS 



Temperature Distribution 



Gulf of Maine Basin: 

 Surface Layer (0-100 meters) 



Surface waters in the Gulf of Maine Basin 

 (that region north of the 50 fathom (91.4 m.) 

 isobath along the Eastern and South Channel 

 slopes) tended to be slightly warmer in 1969 than 

 in 1968. In 1968 surface isotherms ranged from 

 3°-^° C' whereas in 1969 they ranged from 4°- 

 5° C. This 1.0° C. difference (in surface waters) 

 was also evident in the upper 100 meters in the 

 same region as shown by temperature profiles 

 (figs. 15-17 and 47-49). Both years were char- 

 acterized by weak temperature gradients. How- 

 ever, the gradients in 1968 tended to be vertical, 

 wliereas in 1969. they were more horizontal. On 

 ICNAF 68-1, a pocket of very cold water (2.0° 

 C.) was observed at station 8, extending from 

 the surface down to 50 meters. Other than this 

 small pocket, waters in this region appeared to 

 be very well mixed. 



The temperature of the upper 100 meters of 

 water is governed mainly by local climatic influ- 

 ences. "The gulf owes the particular tempera- 

 tures proper to it, and especially the wide seasonal 

 range of temperature, chiefly to its geographic 

 location to the leeward of the continent and to 

 the rigorous land climate. Only to a much smaller 

 degree is it influenced by warm or cold currents 

 flowing into it," (Bigelow, 1927). Weather 

 records (Local Climatological Data Annual Sum- 

 maries 1967, 1968, 1969, Mariners Weather Logs, 

 and U.S. Coast Guard Weather Observation 

 Logs for various light vessels and light stations) 

 were examined for months preceding and during 

 both cruises. These records show that the 1969 

 winter season was l°-2° C. warmer than that of 



1968. The l°-2° C. deviation is significant in 

 view of the ninety day observation period, the 

 temperature diff'erence between the two years 

 being reflected by the surface water temperatures. 

 Table 1 summarizes air temperatures, wind data, 

 and precipitation observed at selected inland, 

 coastal, and offshore stations. 



The surface radiates out very large amounts 

 of heat from September on, whenever the air is 

 colder than the water. The coldest winter winds 

 of the region blow from land out over the gulf, 

 and tliese cold westerly winds predominate in the 

 western side of the gulf during the three winter 

 months (Bigelow, 1927). 



