collect water in exactly the same stratum on 

 successive casts. 



The significance of phaeophytin a and 

 phaeophorbide and their influence upon 

 "chlorophyll a" concentrations was discussed 

 but could not be satisfactorily resolved with 

 the available data. 



4. The technique and equipment used to 

 measure primary production with C-'-'' are 

 discussed in some detail. They follow rather 

 closely those used by Steemann-Nielsen ( 195Z). 

 Between 1 and 2,0 iic, per ml. of sterile C^^ 

 was stored in 5- to 15-ml. glass ampules. One 

 or more ampules of appropriate Ci-^ strength 

 was used at each station; about 1 nnl. of the 

 C-'-'* solution was added to the 125-ml. sea 

 water sample with a constant delivery syringe. 

 The activity of the C^'* solution was measured 

 by barium precipitation of the radioactive 

 carbonate on tared Millipore filters. The 

 standards, samples, and background were 

 counted until at least 1,280 disintegrations 

 had been obtained. 



One of the main difficulties encountered 

 during these investigations was the relatively 

 frequent occurrence of high dark-bottle up- 

 take. No completely satisfactory explanation 

 could be found. 



The following methods of sample incubation 

 were employed: an artificially illuminated 

 incubator maintained at temperatures slightly 

 above sea surface temperatures; deck incu- 

 bators; trailing incubators; and finally in situ 

 incubations. Because two different techniques 

 were generally used simultaneously, compari- 

 sons of the rates of C-'-'^ uptake between dif- 

 ferent methods could be made. Non-parametric 

 statistical methods were used to show that the 

 results of the different paired incubation tech- 

 niques were significantly correlated. This 

 correlation demonstrated that the different 

 incubation techniques yielded unbiased esti- 

 mates of in situ productivity. However, be- 

 cause the degree of correlation, even though 

 statistically significant, varied appreciably, 

 the accuracy of the extrapolation from in- 

 cubator measurements to in situ productivity 

 can be expected to vary with the method of 

 incubation. 



LITERATURE CITED 



BERGE, GRIM. 



1958. The primary production in the Nor- 

 wegian Sea in June 1954, measured by 

 an adapted C -'■'^ technique. In measure- 

 ments of primary production, Cons. 

 Perm. Int. Explor. Mer, Rapp, Proc.- 

 Verb. Re'un. 144: 85-91. 



BLACK, J. N. 



1956, The distribution of solar radiation 

 over the earth's surface. Arch. Mete- 

 orol. Geophys. Bioklimatol. 7, Ser. B: 

 165-189. 



BLACKBURN, MAURICE, RAYMOND C. 

 GRIFFITHS, ROBERT W. HOLMES, and 

 WILLIAM H. THOMAS. 

 1962. Physical, chemical, and biological 

 observations in the eastern tropical 

 Pacific Ocean: three cruises to the 

 Gulf of Tehuantepec, 1958-59. U.S. Fish 

 Wildl. Serv., Spec. Sci. Rep. Fish. 420, 

 iii + 170 pp. 

 BORTKOVSKII, R. S. 



1961. K metodike raschetov elementov 

 teplovogo balansa poverkhnosti okeanov. 

 (Concerning the method of calculating 

 the constituents of the heat bal- 

 lance in the surface of the oceans.) 

 Okeanologiia, 1(3): 512-521. [English 

 translation in Deep-Sea Res. 9: 

 362-370.] 

 BUDYKO, M. I. 



1956. Teplovoi balans zemnoi poverkhnosti. 

 (The heat balance of the earth's 

 s u r f a c e.) Gidrometeorologicheskoe 

 Izdatel'stvo, Leningrad, 255 pp. [English 

 translation by U.S. Departnnent of Com- 

 merce, Weather Bureau, Washington, 

 D.C., 1959.] 



BURDECKI, F. 



1958. Remarks on the distribution of solar 



radiation over the surface of the earth. 



Arch, Meteorol., Geophys. Bioklimatol., 



8, Ser. B: 326-335. 

 DOTY, MAXWELL S., and MIKIHIKO OGURI. 



1957. Evidence for a photosynthetic daily 

 periodicity. Limnol. Oceanogr. 2(1): 

 37-40. 



DRUMMOND, A, J, 



1961. Current developnnents in pyrhelio- 

 metric techniques. Solar Energy 5(1): 

 19-23. 

 FOSTER, NORMAN B. 



1951. A recording daylight illuminometer. 

 Ilium. Eng. 46(2): 59-62. 

 HOLMES, ROBERT W., and MAURICE BLACK- 

 BURN. 



1960. Physical, chemical, and biological 

 observations in the eastern tropical 

 Pacific Ocean, SCOT Expedition, April- 

 June 1958. U.S. Fish Wildl. Serv., Spec. 

 Sci. Rep. Fish. 345, iii + 106 pp. 



HOLMES, ROBERT W., and ROBERT J. LINN. 



1961. A modified Beckman Model DU spec- 

 trophotometer for seagoing use. U.S. 

 Fish Wildl. Serv., Spec. Sci. Rep. Fish. 

 382, iv + 4 pp. 



HOLMES, ROBERT W., MILNER B, 

 SCHAEFER, and BELL M. SHIMADA. 

 1957. Primary production, chlorophyll, and 

 zooplankton volumes in the tropical 

 eastern Pacific Ocean. Inter-Amer. 

 Trop. Tuna Comm., Bull. 2(4): 128-169. 

 [English and Spanish.] 

 HOLMES, ROBERT W., and JAMES M. 

 SNODGRASS. 

 1961. A multiple -detector irradiance meter 

 and electronic depth-sensing unit for 



29 



