cycle of the dominant species. A bicyclic annual course of development of 

 plankton is characteristic for the entire zone; the specifics of develop- 

 ment of plankton is characteristic for the entire zone; the specifics of 

 development of phytoplankton and zooplankton in the waters of the North 

 Atlantic and North Pacific differ somewhat. In the North Atlantic, with 

 domination of Calanus finmarchicus , the annual maximum of zooplankton 

 biomass follows the spring annual maximum of phytoplankton with some delay, 

 while the autumn, smaller, maximum of phytoplankton is followed by a small 

 autumn rise in the biomass of zooplankton. Significant consumption of 

 phytoplankton by zooplankton begins a few weeks after the beginning of 

 development of the phytoplankton and coincides with the appearance of the 

 II and III copepodites--soon after the massive spawn of C^. finmarchicus 

 having survived the winter (Gushing, 1975). It is characteristic of the 

 temperate waters of the North Atlantic on the whole that the spring peak of 

 development of phytoplankton is greater than the fall peak, and that the 

 amplitude of the fall peak varies from yesr to year. 



In the northwest Pacific and the Bering Sea, where the common species 

 in zooplankton are C^. cristatus , C_. pacificus , C. p lumchrus and Eucalanus 

 bungii (the first three species are Pacific analogs of the North Atlantic), 

 the bicyclic development of phytoplankton, "normal" for temperate waters, 

 is observed only in the neritic regions. In the oceanic regions, only 

 a fall maximum of biomass of phytoplankton is observed, while the annual 

 maximum of zooplankton biomass occurs in the spring and summer, when the 

 phytoplankton is rather abundant (Heinrich, 1951a). 



The duration of the production cycle of plankton varies from one 

 month to one year, averaging three months for phytoplankton and six to 

 seven months for zooplankton. The fluctuations in production cycles of 

 plankton from year to year reach two or three orders of magnitude as to 

 population of algae and one or two orders for the biomass of animals. The 

 differences between the mean values for different years in the same regions 

 are less than between different seasons in the same year (Gushing, 1975). 



The mean value of annual production of planktonic phytophages in 

 productive regions, where they represent most of the biomass in the 0-500 m 

 layer, has been estimated as 200-300 mg/m3 (Greze, 1973a). 



We must note one important specific feature of the cold-temperate 

 regions of the northern hemisphere which is becoming more significant with 

 each passing year: the continuous increase in the effects of anthropogenic 

 factors on the plankton communities, particularly water pollution. These 

 waters wash the shores of the most industrially developed countries in the 

 world, and their coast sections are the most polluted portions of the world 

 ocean. Pollution has a significant and ever increasing effect on the biology 

 of plankton communities in most regions in this zone. To illustrate this 

 statement, it is sufficient to present two examples. In the northwestern 

 Atlantic, over the edge of the continental shelf and somewhat further out 

 to sea, lumps of tar floating on the surface now equal more than 20% of 

 the wet weight of all neuston (Morris, 1971). Between Hawaii and Japan for 

 mile after mile, one observes films of copepod remains, which have died as 



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