Of all the systematic errors of the radiocarbon method, the most 

 important are errors in determination of the stock activity of the 

 solution and in filtration. Differences in methods of determination of 

 the stock activity are particularly significant when window- type 

 counters are used, amounting to 10-20% or even 30% (Jitts, Scott, 1961; 

 Sorokin, 1963; Steemann Nielsen, 1965). Recently, most researchers have 

 begun using scintillators; therefore, this source of error has become 

 less significant. 



The basic criticism of the radiocarbon method concerns the loss of 

 a portion of the synthesized organic matter by filtration, acid 

 treatment, storage, and drying of filters. Filtration causes a loss of 

 dissolved assimilates and organic matter formed by Flagellata and other 

 algae which pass through the filters either whole or in damaged form, 

 acid treatment results in loss of easily hydrolyzed carbohydrates, while 

 drying and storage results in loss of volatile compounds such as 

 volatile acids and ketones. Most numerous are works dedicated to the 

 losses of dissolved organic matter by filtration. After summarizing the 

 data of a number of authors, we have come to the conclusion that these 

 losses, in the surface layer and throughout the entire euphotic layer, 

 are usually as follows: with primary production of <150 mg Cm'^ per 

 day— 5-50%: with production of 150-250 mg C/m^ per day— 5-30%; at 250- 

 500 mg C/m^ per day --20%, at >500 mg C/m^ per day— < 10%. 



Pigments . In addition to the primary production determinations, 

 productivity is frequently evaluated using the data on quantity of 

 nutrient salts, phytoplankton, the content of suspended matter, ATP or 

 photosynthetic pigments. The later (usually chlorophyll a) is 

 particularly frequently used. At the present time, a quantitative 

 relationship has been obtained between the concentration of chlorophyll 

 and primary production. It is still more important to note that the 

 content of pigments allows us to relate the results of determination of 

 photosynthesis to their quantity, and thus perform the physiological 

 analysis of the production process. 



Determination of pigments in a sample of sea water can be conducted 

 chromatographically, fluorometrically, or by standard spectrophotometric 

 methods, the latter being used in most investigations. Its principle 

 were developed by Richards and Thompson (1952), then further improved 

 (Parson, Strickland, 1963; SCOR UNESCO, 1966). A comparison of the data 

 obtained using the formulas of Richards and Thompson (taken as unity) 

 and derived on the basis of the new specific coefficients of extinction 

 of chlorophylls, the equations of SCOR UNESCO, and Parsons and 

 Strickland is presented below. 



Author 



Chloro- 

 phyll a 



Chloro- 

 phyll b 



Chloro- 

 phyll c 



Richards, Thompson, 1952 

 Parsons, Strickland, 1963 

 SCOR UNESCO, 1966 



1.00 

 0.76 

 0.74 



00 

 05 

 36 



1.00 

 0.57 

 0.53 



231 



