station Numbers 



o 



M 

 111 



3 

 _l 

 < 

 > 



0.90- 



085- 



075- 



70- 



060- 



©®®®@®®0®©©®®© 



Fig. 



21. Dendrogram of J^^ values (as for qualitative data) at stations in the 

 Chukchi Sea. 



in this pelagic zone is characterized by mass conglomerations 

 of furcilia of euphaussiids. Their share in the total biomass of 

 zoocenosis averaged 33%. 



The community of waters of central stations (Stations 55 

 and 64) was inhabited by meroplankton organisms (45% of 

 number and 30% of biomass ). It is believed essential to note a 

 relatively high amount of appendiculariansfnf(7/aWa borealis, 

 whose biomass exceeded the biomass of another mass species 

 of appendicularians, Oikopleura labradohensis, which 

 dominated in the northwest region of the sea. 



Discussion 



Comparison of the study data and materials obtained 

 during previous multipurpose ecologic expeditions of LAM in 

 the Bering Sea in June 1981 and July 1984 (Kosolova et al, 

 1987; Kulikov, 1990) testifies to an insufficient variability of 

 qualitative and quantitative parameters of mesozooplankton 

 communities as a result of their seasonal development. At the 

 East Polygon (1988, August), the Oithona similis population 

 reached its maximum leading to a 1.5-2.0 increase of 

 mesozooplankton abundance. Total biomass values showed 

 the same rate of decrease due to seasonal migration of older 

 copepodite stages of Calanus plumchrus and C. cristatus. To 

 the west of St. Lawrence Island, in the region of sampling 

 stations of eadier expeditions, at the North Polygon (1988, 

 August — Stations 32, 35, 36, and 4 1 ), we defined a zone with 

 a high level of zooplankton biomass that was formed due to 

 transport of a great amount of large oceanic species of copepods 

 with the Anadyr Current. Compared to July of 1981, the 

 situation has changed. The abundance level decreased three 

 times, while the biomass increased two times. In the southern 

 part of the sampling area there was a similar pattern of variation 

 of organism abundance; still, their peak value was three times 

 larger. Total biomass of community in this region remained 

 relatively the same between the years. 



5.2.3 Some Characteristic Features of Epipelagic 

 Necrozooplankton Distribution 



ANDREY S. KULIKOV 



Institute of Global Climate and Ecology, State Committee for Hydrometeorology and Academy of Sciences. Moscow. USSR 



Introduction 



One of the most important indices of the biological 

 component state of marine ecosystems at the organismic 

 population and community level is biological characteristics, 

 including ecological mortality (Odum, 1975). Ecological or 



realizational mortality is considered to be the destruction of 

 organisms; in particular, the conditions of the environment and 

 its changing characteristics, in accordance with the firm 

 conditions of habitat and state of affected populations and 

 communities (Koval, 1984). Mortality is expressed both by the 



172 



