detected in the coastal areas near the Chukchi Peninsula and 

 Alaska. The average values for the total number and biomass 

 of microorganisms for the whole of this sea amounted to 

 0.92 X 10" cells/ml and 20.7 |j.g C/1, making them higher than 

 in the Bering Sea. 



The values for bacterial destruction of organic matter in 

 the Bering Sea in 1988 varied over a two order of magnitude 

 range (4.8-435.5 [ig C/l/day). Maximum values of bacterial 

 destruction were found in the central and southern areas of the 

 sea ( 107.3 |ig C/l/day at the East Polygon and 7 1 .2 |ig C/l/day 

 at the South Polygon [see Frontispiece]). The production of 

 bacterial biomass in the Bering Sea varied over the range of 

 1.5-136 |ig C/l/day, averaging 17.3 |ig C/l/day for the entire 

 region. In the Chukchi Sea, bacterial production varied from 

 6.4-215 |ig C/l/day, averaging 20.2 |ig C/l/day. The highest 

 values were found in the open waters of the southern Chukchi 

 Sea and in the coastal zone of Chukchi Peninsula, which were 

 26.8 and 26.2 \ig CAl/day, respectively. 



The results of special microbiological observations 

 reflected a significant heterogeneity in the water column. 

 Bacterial production studies using cell division frequency and 

 thymidine incorporation varied over the range of 

 1-5 X lO^cells/hintheChirikovbasin. Comparison of data on 

 bacterial production versus phytoplankton production indicated 

 that phytoplankton accounted for 5-33% of the total amount of 

 carbon assimilated during primary production. 



The generic composition of heterotrophic saprophytic 

 microflora in the Bering Sea was as follows: Pseudomonas 

 (26.8%); Bacillus (23.4%); Pkmococcits (\1 .%%): and lesser 

 abundances of Xanthomonas, Alcaligenes, Halobaclehiim. 

 Flavobacterium, Micrococcus, Aerococcus, andArthrobacter. 

 The genera in the Chukchi Sea were not so diverse: Pseiidomomis 

 (45%); Bacillus (18.2%); Flavobacterium (9.1%); and 

 Staphylococcus (9.1%). Also species in the following genera 

 were frequently observed: Xanthomonas. Alcaligenes. 

 Klebsiella. Aeromonas, Micrococcus. Planococcus. and 

 Art/iro/7ac?cr. Thus, the taxonomic composition of the microbial 

 cenoses of the Bering Sea proved to be more diverse than the 

 Chukchi Sea. 



Laboratory experiments on isolated strains of bacteria 

 from these regions also possessed variable resistance toward 

 antibiotics and heavy metal salts. This reserve indicates the 

 presence of extrachromosomal genetic elements of the plasmid 

 type in their cells. Further experiments on some isolates from 

 the region showed that representatives of different taxonomic 

 groups possessed the ability to synthesize metabolites that had 

 mutagenic and genotoxic (RNA-damaging) potentials. The 

 RNA-damaging effect was strongest in certain pseudomonad 

 species that actively develop in conditions of marine pollution, 

 especially when dense populations ( lOto lOOx 10" cells/ml) of 

 these microorganisms are found. The predominance of 

 pseudomonads in impacted regions of the world oceans may be 

 an indicator of secondary pollution of the marine environment. 

 The absolute numbers of anthropogenic indicator microflora in 

 the Bering and Chukchi Seas are not large, but the observed 



trend toward an increase in their number and distribution 

 confirms the necessity for increased controls over man-made 

 pollutants and the need to continue to carry out systematic 

 observations aimed at the development of scientifically based 

 protection measures. 



The study of the phytoplankton abundance and productivity 

 constituted a major focus of this expedition. In the Chirikov 

 basin, cell counts ranged between 0.5 and 

 1.7 X 10" cells/1, while in the central Bering Sea, these were 

 0.1-2.4 X 10" cells/1. In the Gulf of Anadyr, the counts were 

 similar to those of the central Bering Sea. There was a general 

 trend for diatoms and peridinians to be numerically dominant 

 in more northern waters, while cyanophytes were most numerous 

 toward the south. Biomass dominance was maintained by the 

 diatoms and peridinians throughout the area. Quantitative 

 measures varied sharply from station to station and with depth. 

 The observed heterogeneity is due to the hydrographic 

 complexity of the region. The standing stock of phytoplankton 

 of the northern Bering Sea is dominated by small nanoflagellates 

 (<10 m). These represent about 63% of the biomass both in 

 terms of integrated carbon and cell numbers. 



Chlorophyll distribution measurements support the 

 hypotheses for advective flow of deep nutrient-rich oceanic 

 water moving northward. At the East Polygon, an area on the 

 shelf edge, elevated chlorophyll amounts were measured, 

 indicating that nutrient rich oceanic water was upwelling and 

 cycling into the Gulf of Anadyr. Large chlorophyll 

 concentrations observed in the Gulf of Anadyr and Anadyr 

 Strait merge as the Bering Shelf water flows northward toward 

 the western edge of the Bering Strait. Once into the Chukchi, 

 the flow travels initially in a northwesterly direction. High 

 chlorophyll concentrations were frequently observed throughout 

 the Chukchi basin; however, there was no obvious pattern. 



High Performance Liquid Chromatography analysis of 

 pigment samples from throughout the study area allowed 

 fractionation of several pigment types. These pigments served 

 as source markers for inferring distributions of major algal 

 groups in this region. The most abundant accessory pigments 

 detected were chlorophyll r, diadinoxanthin. and fucoxanthin, 

 which suggest the dominance of diatoms in the Gulf of Anadyr 

 and the Chukchi Sea. Green algae abundance was indicated by 

 the presence of chlorophyll b and peridian pigments in a band 

 extending from north of St. Lawrence Island through the 

 Bering Strait and into the Chukchi Sea. Chrysophytes and 

 pry manisiophytes were present in waters overlying the Chirikov 

 basin and the central and southern regions of the Bering Sea 

 (the unique pigments for these groups are 

 19'-hexanoyloxyfucoxanthinand 19'-butonoyloxyfucoxanthin). 



Optical measurement techniques for monitoring 

 particulates in the watercolumn were employed to intercompare 

 with the more conventional techniques. The findings in most 

 cases were in good agreement and served to validate each other. 

 Angular and integral light scattering were typical of diatomic 

 slurries in the Gulf of Anadyr and divergence zones in the 

 Chukchi Sea. Zonal charts of diatomic slurries identified by 



400 



