Our calculations showed that in the Bering and Chukchi Seas 

 the correlation factor between C^ and the residence time of 

 "■"Th, T-^ in various water layers was high, r = 0.86 (n = 26). 

 The data gathered for -'*U and -'""Th concentrations in 

 seawater made it possible to estimate the following 

 biosedimentation parameters: 



— rate of biosedimentation at specific depths; 



— the POM concentrations; and 



— the residence time of POM in the water column. 

 These results are presented in Tables 4 and 5, and in Fig. 1. The 

 biosedimentation parameters varied considerably within the 

 region studied. This was due both to the specific hydrody namic 

 conditions found and to the structural and functional features of 

 the ecological systems under study. 



In the Bering Sea, the biosedimentation rate was 



46.5 ± 5.3 mg dry weight m ' d ' with an average POM 



concentration of 0.98 ± 0.04 mg dry weight m \ The average 



residence time of POM in the water column was about one 



month (29.7 ± 2.9 days). 



Within the Bering Sea, different regions had highly varied 

 biosedimentation rates. In the Gulf of Anadyr, the 

 biosedimentation parameters had the lowest values. The rate 

 of biosedimentation ranged from 12.0 to 

 30.0 mg dry wt m' d '. POM concentration averaged 

 0.86 ± 0.05 g dry wt m ' (n = 9) and, as a rule, did not exceed 

 l.Ogdry wt/m'. The residence time of POM ranged from 16.5 

 to 26. 1 days at 80-1 20 m depth, and up to 53.3-65.2 days in the 

 euphotic zone. 



In the region north of St. Lawrence Island, the 

 biosedimentation parameters featured a relative evenness in 

 their vertical profiles. The biosedimentation rate amounted to 

 110.4mgdry wtm'd' at some depths and high concentrations 

 of POM, more than 1 .0 g dry wt m \ were found throughout the 

 water column. These are approximately the same values 

 observed in the open sea. However, in this region significant 

 changes in the vertical profiles of the biosedimentation 

 parameters were noted. The maximum rates of POM removal 

 were noted above the thermocline at 20-m depth. 



TABLE 4 



Biosedimentation parameters in the Bering Sea. 



228 



