consumption, sediment mineralization, and resuspension by 

 benthic-feeding marine mammals inhibit fine sediment and 

 organic carbon accumulation in this region. 



In conclusion, the shallow continental shelfof the northern 

 Bering and Chukchi Seas exhibits a direct coupling of water 

 column primary production to secondary benthic production 

 and carbon cycling. The deposition of a high quantity and 

 quality of organic carbon to the western regions of this area 

 supports extremely high populations of benthic fauna, which in 

 turn provide a large food source for benthic-feeding marine 

 mammals. Shallow marine shelves in polar regions are important 

 sites for carbon cycling and are likely to be directly impacted 

 by global climate changes. 



Many thanks to the following people for assistance at sea during 

 the study; D. Adkison, D. Veidt, T. Whitledge, V. Koltun, and 



B. Sirenko. L. Cooper performed all of the required chemical 

 extractive procedures and vacuum line manipulations, while D. Winter 

 performed the mass spectrometric analyses. Thanks to D. Hammond 

 for suggestions and laboratory support during postdoctoral work at 

 the University of Southern California. C. R.Olsenandl. L. Larsenof 

 the Environmental Sciences Division, Oak Ridge National Laboratory, 

 provided valuable technical advice and additional radionuclide 

 analyses. Financial support was provided by NSF grants DPP 88- 

 13046, DMB 84-05003, DMB 88-96201. and DOE grant 

 87-ER606I5. This project was part of the Third Joint US-USSR 

 Bering & Chukchi Seas Expedition aboard the Soviet 

 research vessel Akademik Korolev. I express appreciation 

 to the US Fish and Wildlife Service, USA, and the 

 State Committee lor Hydrometeorology, USSR, who made 

 participation on the project possible. Finally, I thank the captain 

 and crew of the R/V Akademik Korolev for cooperation in the field. 



7.2 Characteristics of Benthic Biocenoses of the 

 Chukchi and Bering Seas 



BORIS I. SIRENKO and VLADIMIR M. KOLTUN 



Zoological Ii\stilHte. USSR Academy of Sciences, Leningrad. USSR 



Introduction 



Benthic fauna of the boreal and southern regions of arctic 

 waters of the World Ocean are characterized by relatively high 

 faunal diversity and biomass. Thus, the benthos plays a very 

 important role in the energy balance of the marine ecosystem. 

 At the same time most benthic organisms are quite sensitive to 

 various environmental effects. In recent years the most 

 prominent effect has been exerted by anthropogenic factors 

 that have been increasing annually. In this respect, global 

 ecological monitoring of the World Ocean is becoming more 

 and more vital (Izrael & Tsyban, 1985). 



The present article is a continuation of the work started in 

 1977 by the USSR Committee on Hydrometeorology and 

 Environmental Control in the Bering Sea. In 1988, the group 

 of scientists that studied problems of the benthos during the 

 47th cruise of the research vessel {RfV) Akademik Korolev put 

 forward the following tasks: J. definition of the structural 

 characteristics of benthic communities in the regions covered 

 by the expedition; 2. analysis of the quantitative distribution of 

 benthic fauna; and 3. determination of annual variations in the 

 structure of benthic ecosystems, if any, and reasons for these 

 variations. 



It should be noted that the regions studied were selected 

 based on data available from previous investigations. First 

 attempts to quantitatively study characteristics of the benthos 

 in the northern part of the Bering and Chukchi Seas were made 

 in 1 933 during the cruise of the R/V Krasnoanneyets (Deryugin 

 (felvanov, 1937;Makarov, 1937). Then, from 1950-52, more 

 detailed studies of qualitative and quantitative characteristics 



of the benthos of the northwestern part of the Bering Sea were 

 carried out during the cruise of the RA' Vityaz ( Vinogradova, 

 1954;Zenkevitch&Filatova, 1956;Belyaev, 1960;Filatova& 

 Barsanova, 1964). Eastern and central parts of the Bering Sea 

 were thoroughly studied during several cruises as part of Soviet 

 expeditions in 1958-1960 (Neiman, 1963) and by American 

 scientists in 1970-1974 (Alton, 1974;Stoker, 1981). In recent 

 years investigations of the Bering and Chukchi Seas benthos 

 were carried out by both Soviet (Sagaidachny & Chistikov, 

 1987) and American scientists (Grebmeier era/., 1988, 1989; 

 Grebmeier & McRoy, 1989). 



On the basis of prior research and the present study, we 

 investigated the annual variations of some benthic biocenoses 

 and their quantitative characteristics in the Bering and Chukchi 

 Seas. 



Material and Methods 



Samples of benthic fauna collected in 1988 during the 47th 

 cruise oiiheRN Akademik Korolev in the Bering and Chukchi 

 Seas were used as materials for the present study. A total of 1 59 

 macrobenthic samples from 86 stations were collected during 

 the cruise, including 48 samples collected with a trawl and 1 1 1 

 samples collected with a dredger. Of the dredger samples, 25 

 were tested for qualitative parameters, with the remainder 

 analyzed for quantitative parameters. In addition, meiobenthic 

 samples were obtained at 46 stations. 



Samples were collected in three main regions: the Gulf of 

 Anadyr and neighboring waters (14 trawl samples and 26 

 dredger samples); the northern Bering Sea from St. Lawrence 



251 



