Chukchi Sea 



Fig. 1. Distribution of primary production in the Bering and Chukchi Seas 

 (July-August, 1988). Values are represented in mg C/m- day. 



was 980 and 290 mg C m- d ', respectively (Table 1). The 

 level of primary production at stations located in the gulf itself 

 varied from 470 mg C m- d' at Station 19 to 

 3,200 mg C m - d ' at Station 32 (Table 1). 



The average value of primary production in the Gulf of 

 Anadyr was 1,850 mg C m - d ', and the average value of the 

 P/B coefficient was 0.8. It should be noted that the highest 

 values of phytoplankton production were obtained in the western 

 part of the gulf (Tables 1.2). In the eastern part of the gulf, the 

 production of phytoplankton was considerably less (Fig. 1 ). 



The research on determination of primary production of 

 phytoplankton in the Chirikov Basin showed that in the middle 

 of August, the value of primary production was approximately 

 1,800 mg C m' d ' in the western part of the gulf, 

 600 mg C m- d ' in the central part, and only 

 320 mg C m - d ' in the eastern part of the gulf (Table 1 ). 



It should be noted that the peculiarities of the distribution 

 of primary organic production in the northwestern and northern 

 regions of the Bering Sea observed during the expedition are 

 very closely correlated with the quantity of nutrients and the 

 quantity of phytoplankton in these regions of the sea. 



Thus, according to the results obtained by the American 

 research workers who participated in the expedition on board 

 the RTW Akademik Korolev, the stations richest in nutrients and 

 chlorophyll a were situated in the western part of the research 

 area. An especially high concentration of chlorophyll a 

 (55 mg Chi m') was discovered in the Gulf of Anadyr. High 

 productivity of the Gulf of Anadyr waters can be explained by 

 the topographically induced rise of deep waters. These waters 



are rich in nutrients and are brought into the photosynthetic 

 zone by the transverse current along the shelf The same 

 current, which provides high productivity of the Gulf of 

 Anadyr, moves further on to the north, along the eastern Soviet 

 coast and Saint Lawrence Island into the Chirikov basin. 

 Situated between Saint Lawrence Island and the Bering Strait, 

 the Chirikov Basin differs significantly from the Gulf of 

 Anadyr. Cold waters, rich with nutrients, are located along the 

 Chukchi coast. Alongthecoastof Alaska, however, there are 

 low- salinity, low-nutrient shelf waters, which result from 

 runoff from the coast. According to the data obtained by the 

 American specialists, the concentration of chlorophyll a in this 

 area was only 1-5 mg m - at that time. 



The investigations in the southern part of the Bering Sea 

 were performed at the end of August, in the region called South 

 Polygon. The amounts of phytoplankton production at stations 

 in this region were comparatively small, 40-105 mg C m - d ', 

 which seems to be typical for the period of biological autumn. 

 During the expeditions on the RA"s Shirshov and Akademik 

 Korolev, in 1981 and 1984, this region was investigated one 

 month earl ier in the period of the middle of biological summer. 

 Naturally, the values of primary production measured at that 

 time were a bit higher for this region: on average, 

 190-320 mgCm-d'(Tsybanf/ a/., 1985). At the same time, 

 the values of P/B coefficient were 0.11-0.71. This indicates 

 relatively high intensity of photosynthesis, which is an important 

 characteristic for the period of biological summer. The values 

 of P/B coefficient during the third ecological expeditions on 

 the stations of this region were 0.40-0.56. 



Concerning vertical distribution of primary production in 

 the Bering Sea, it should be noted that, similar to the research 

 of 1981 and 1984, the depth of the euphotic zone during this 

 time did not exceed 45 m (Tables 1,2). As a rule, the vertical 

 profiles of primary production had a maximum located within 

 the area of optimal light conditions at 5- 1 m or more seldomly 

 in the surface layer. The values of primary production below 

 this maximum decreased monotonically (Tables 1 ,2). 



Consider that the average of the primary production of 

 phytoplankton at the stations in the Bering sea was about 

 2,200 mg C m- d ', according to our data. Furthermore, 

 according to the data obtained by V. M. Kudryatsev (Subchapter 

 4. 1 .2, this volume), the average of bacterial degradation in the 

 photic zone of the Bering Sea during the period of our research 

 work was 6, 1 00 mg C m - d ' . The value of the P/D - coefficient, 

 which was used as an indicator of the balance between the 

 processes of synthesis and destruction of organic substances in 

 the Bering Sea ecosystem, was 0.36 during the period of the end 

 of biological summer to the beginning of biological autumn. 



Besides the studies of the Bering Sea ecosystem during the 

 course of the expedition on board the R/V Akademik Korolev, 

 we pert'ormed ecological pelagic research of the eastern sector 

 of the Arctic basin, that is, the Chukchi Sea. The average value 

 of primary production in the southern part of this sea was 

 1,700 mg C m - d '. This fact indicates that the productivity of 

 this area of the Chukchi Sea is very high (Table 2). The highest 

 rates of photosynthesis were discovered in the central part of 

 the basin, at Station 55 (Table 2). The minimum values of 

 phytoplankton production were obtained in the course of 



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