Station 2. 



10 20 30 40 % 



Station 11. 



1000 



_] I I I I I 1 L 



2000 3000 ind/r 



10 



20 



30 



I 



40 



3000 8000 

 J 1 I I 



- number of necrozooplankton (ind/m ) 



^^H - percentage of necrozooplankton in total 

 zooplankton community (%) 



Fig. 1. Vertical distribution of necrozooplankton at Station 2. 



vertical distribution of necrozooplankton coincided with depth. 

 At Stations 5, 1 l.and 15, dead organisms were concentrated in 

 the warm upper layer and upper layer of the thermocline ( 10 

 and 25 m). Here, their numbers reach 7,500 ind/m' which 

 constitutes 34% of the zooplankton (Fig. 2), and biomass was 

 100 mg/m' or 40% of the total. The vertical structure of 

 necrozooplankton at Stations 7, 9, and 13 were characterized 

 by maxima in the cold intermediate layer (70-100 m; Fig. 3). 

 The accumulation of dead animals numbered 1,100 ind/m' 

 (39%), and biomass. 31 mg/m' (38%). 



The vertical distribution of necrozooplankton in the shelf 

 regions of the Bering and Chukchi Seas was similar to those 

 found in the deep-water regions. Accumulation of dead 

 organisms, as a rule, was located either at the surface to the 

 discontinuous layer at a depth of 25— 45 m (which divided warm 

 upper and intermediate cold water masses) or to the 70 m layer 

 (where there was a boundary of distribution for intermediate 

 cold and near-bottom warm layers, as at Station 24). In the 

 absence of stratification of water masses (homothennal -and 

 homosalinal) — for example, at Station 96 — necrozooplankton 

 were concentrated in large amounts at the near-bottom horizon, 

 5,400 ind/m', forming 44% of the total number, and 27 mg/m', 

 comprising 35% of the total biomass. In most cases, significant 

 high absolute numbers coincided in depth with peak percentages 

 of the dead fractions. 



Analysis of the variability in the levels of quantitative 

 indices for necrozooplankton distribution under a square meter 

 of surface to the layer of 0-100 m enabled the identification of 

 zones with increased concentrations in the Bering and Chukchi 



- number of necrozooplankton (ind/m ) 



^^H - percentage of necrozooplankton in total 

 zooplankton community (%) 



Fig. 2. Vertical distribution of necrozooplankton at Station 1 1 . 



10 



Station 13. 



20 30 



40 % 



2000 3000 



J I I I I I I L. 



ind/m 



- number of necrozooplankton (ind/m') 



- percentage of necrozooplankton in total 

 zooplankton community (%) 



Fig. .1. Vertical dislnhulion of necrozooplankton at Station 13. 



174 



