Foreword 



In the last few years, an ever-growing anthropogenic 

 impact on different natural ecosystems and the adverse effects 

 resulting from this impact have led humanity to reali/e the real 

 threat of potential global ecological disasters and to give a high 

 priority to environmental protection. 



Natural factors cause the bulk of nearly all man-made 

 chemicals to eventually enter the World Ocean, which, owing 

 to this, can be considered a tremendous reservoir/accumulator 

 of contaminants. Elimination of these contaminants through 

 natural processes of the ocean (i. e.. self-purification) occurs 

 through a complex system of physical, chemical, and biological 

 processes taking place in the ocean. However, conditions 

 favorable for the existence of certain hydrobionts that were 

 established over whole geological epochs are being disturbed 

 by these anthropogenic impacts. For these reasons, it is 

 obvious that while studying ocean pollution and its ecological 

 consequences, it becomes necessary to have complex physical, 

 chemical, and biological investigations, which calls for 

 principally new, interdisciplinary approaches to the solution of 

 this problem. 



The protection of the marine environment against the 

 undesirable influence of anthropogenic factors are global 

 problems common to all mankind. They can, and must, be 

 solved by joint efforts of scientists from different countries. 

 For this reason, and taking into consideration that the Bering 

 and Chukchi Seas wash the US and USSR coasts (countries 

 equally interested in the further fate of these unique regions of 

 the World Ocean), it was considered appropriate that the efforts 

 and knowledge of scientists of both countries be joined to study 

 the state of the ecosystems of these seas. 



It is important to note that 1992 is the 20th anniversary of 

 the US-USSR Agreement on "Cooperation in the Field of the 

 Protection of the Environment" and the 1 5th anniversary of the 

 beginning of joint US-USSR research within the framework of 

 the special subproject "The Bering Sea." In 1977, 1984, and 

 1988, US-USSR integrated ecological expeditions aimed at 

 investigations of Bering Sea ecosystems were carried out 

 within the framework of the above agreement. These expeditions 

 enabled scientists of both countries to add to the volume of 

 knowledge of this poorly understood body of water. The 

 following are the major research thrusts: a more detailed study 

 of the oceanographic regime; accumulation of data on the 

 spatial (horizontal and vertical) variability of nutrient 

 concentrations; the study of the dynamics of arrival and 

 elimination of the most important pollutants; acquisition of 

 data on the structural and functional characteristics of planktonic 

 and benthic communities; a more detailed study of the 

 microbiological regime; and determination of the role of 

 microorganisms in the biogeochemical cycles of elements in 

 the destruction of organic pollutants. 



Long-term integrated investigations in the Bering Sea 

 began on the first US-USSR expedition on board the R/V 

 Volna in 1977. The scientific results of the expedition were 

 presented in joint monographs published in the US (US Fish 

 and Wildlife Service, 1982) and USSR (Izrael & Tsyban, 

 1 983 ). These investigations were further developed during the 

 expedition canied out by Soviet scientists in 1981 on board the 

 R/V Akademik Shirshov. New scientific data were obtained on 

 the characteristics of the state of the Bering Sea ecosystem, the 

 composition and physiological activity of bacterial populations, 

 quantitative and qualitative composition of microzooplankton, 

 and, investigated for the first time, the biogeochemical cycle 

 of polyaromatic hydrocarbons (using the benzo(a)pyrene as 

 the model compound). Scientific results of the expedition were 

 published in the monograph Comprehensive Analysis of the 

 Bering Seci Ecosystem (Izrael & Tsyban, 1987). 



The Second Joint US-USSR Bering Sea Expedition was 

 carried out on board the RA' Akademik Korolev in 1984. 

 During this expedition, a broad spectrum of questions were 

 studied; they are considered in joint monographs published in 

 the US (Roscigno, 1990) and the USSR (Izrael & Tsyban, 

 1990). 



The Third Joint US-USSR Bering & Chukchi Seas 

 Expedition also took place on board the R/V Akademik Korolev 

 in the summer of 1988. During the expedition, the Bering Sea 

 (already investigated in 1981 and 1984), the Gulf of Anadyr, 

 the Chirikov basin, and the southern Chukchi Sea were 

 investigated (see Protocol of the Third Joint US-USSR Bering 

 & Chukchi Seas Expedition . . . ). In the course of the third 

 expedition, comprehensive studies of the state of Bering Sea 

 ecosystems were continued and investigations in the Chukchi 

 Sea were initiated. The present monograph contains scientific 

 results obtained during the expedition and results which were 

 obtained through //( situ laboratory experiments on samples 

 collected during this expedition. 



The scope of problems elucidated in the monograph is 

 wide: it includes the study of oceanographic aspects, 

 hydrochemical conditions, variability of the spatial structure of 

 planktonic biocenoses, microbial oxidation of organic 

 pollutants, effect of toxic substances on the state of planktonic 

 communities in conditions near to in situ, assessment of the 

 elements of the ecosystem biotic balance, determination of the 

 ratio between the processes of new formation and destruction 

 of organic matter in the Bering Sea ecosystem, and determination 

 of the elements of the biogeochemical cycles of organic 

 pollutants in the Bering and Chukchi Seas. 



The investigations made it possible to conclude that, at 

 present, the ecosystems of the Bering and Chukchi Seas are in 

 a relatively favorable state. However, to maintain this state 

 under conditions of ever-growing anthropogenic impacts from 



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