1961b) and 0. B. Fbkiyevskiy (1960, 1964, 1967) have shown that this 

 impoverishment may be true only of algae, whereas only a few species of 

 animals descend in the tropics, and the indices of quantitative develop- 

 ment of species and biocenoses are almost equal to those of the 

 temperate latitudes, and in many cases even higher. The rule of domina- 

 tion of one or a few species is retained in the tropical biocenoses, but 

 at a lower quantitative level (Mokiyevskiy , 1964). As we move toward 

 the tropics, the specific variety of Rhodophyta and most groups of 

 animals increases, particularly for the crabs, sea urchins, 

 sipunculoids, polychaetes, gastropods and bivalves, etc. Furthermore, a 

 number of systematic groups of high rank, such as Pennatularia, 

 Scl eractinia , Alcyonaria, Zoantharia, hingeless Brachiopoda, Xiphosura, 

 Stomatopoda and Crinoidea inhabit the intertidal zone only in the 

 tropics. Conversely, some large systematic groups which inhabit only 

 the temperate zones Are absent (Mokiyevskiy, 1962). Only a few groups 

 of animals, such as the amphipods and isopods, are present more richly 

 in the temperate waters than in the tropics. In the opinion of 0. B. 

 Mokiyevskiy, the combination of conditions present in the tropical 

 intertidal zone results in a complex interweaving of biocenotic 

 connections between organisms, preventing the realization of short and, 

 consequently, energetically more effective food chains such as are 

 inherent in the biocenoses of the boreal and, particularly, high boreal 

 intertidal zone. 



As we move toward the Arctic and Antarctic, gradual qualitative and 

 quantitative impoverishment of the littoral biota occurs, to the point 

 of complete disappearance in the high Arctic and along a large portion 

 of the coast of Antarctica. Since the harmful, wearing effect of 

 long-term ice cover is particularly strongly felt in the intertidal zone 

 with its surf, the impoverishment in the Subarctic is more strongly seen 

 in intertidal zone areas with surf than in areas with little or no 

 surf. This is clearly seen in the example of Anadyrskiy Bay. Whereas 

 on the rocky intertidal zone with heavy surf the biomass of plants 

 varies from 0.2 g/m^ in a community of Urospora penicilliformis to 3.8 

 kg/m^ in a community of Halosaccion compressum , while the biomass of 

 animals is only 0.5-40 g/m^ in the intertidal zone of Provideniye Bay 

 and Krest Bay, which are protected from the surf, the biomass of plants 

 varies from 88 g/m^ to 11.2 kg/m^, while the biomass of animals may 

 reach 13.5 kg/m^. The clear impoverishment of the littoral biota in 

 Subarctic-type surf habitats occurs primarily due to the complete 

 disappearance of perennial plants and sessile animals. That moving ice 

 is the culprit in this impoverishment is demonstrated by the fact that 

 in summer, stands of fucus or barnacles less than one year old 

 frequently appear here, but mature individuals remain only in clefts and 

 other protected habitats. Seasonal species of algae predominate in the 

 intertidal zone (apparently, the green filamentous algae and diatoms 

 extend furthest north), along with small, mobile animals, capable of 

 concealing themselves in the mats formed by these plants--amphi pods , 

 ol igochaetes, small polychaetes, nematodes, acarines, ostracods, 

 harpacticoids. The mobile multiannual forms of macrobenthos also 

 continue to play some role (Testudinal ia , littorines, nudibranchs, 

 sometimes sea stars, sea urchins and hermit crabs), which winter in the 

 sublittoral or in concealed places. Still closer to the Bering Straits, 

 the population is severely depressed, even in areas protected from the 



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