GENERAL CHARACTERISTICS OF FAR EASTERN SEAS 681 



the bottom topography and the depths of the greatest ocean trenches, the 

 composition and distribution of marine deposits, the composition and distri- 

 bution of deep-water fauna, etc. (Figs. 321 and 322). 



Most of the papers on the survey of the Far Eastern Seas are published 

 in the Bulletin of the Pacific Institute of Fisheries and Oceanography, in the 

 Proceedings of the Institute of Oceanology of the Academy of Sciences of the 

 u.s.s.R. and in the series 'The Exploration of the Seas of the u.s.s.R. ', which 

 was first published by the State Hydrological Institute together with the 

 Pacific Institute of Fisheries and Oceanography. Since 1941 the papers have 

 been appearing under the title The Survey of the Far Eastern Seas of the 

 U.S.S.R., published by the Zoological Institute of the Academy of Sciences, 

 and in the periodicals The Survey of the Seas of the U.S.S.R., The Fauna of 

 the U.S.S.R., and The Proceedings of the Zoological Institute of the Academy 

 of Sciences of the U.S.S.R. published by the same institute. 



III. PHYSICAL GEOGRAPHY OF NORTHWESTERN PART 

 OF PACIFIC OCEAN 



Coastline and bottom topography 



The coastline, bottom topography, circulation of the water masses and some 

 phenomena of their geological past are the most characteristic features of 

 these Far Eastern Seas. 



The northwestern part of the Pacific Ocean is characterized by a rich 

 development of coastal features and by the presence of numerous islands 

 which form three great arcs — namely, the Japanese, Kuril and Aleutian, and 

 the Alaska and Kamchatka Peninsulas, which cut off the Seas of Japan and 

 of Okhotsk and the Bering Sea from the Ocean. The hydrology, chemistry and 

 biology of the three Seas bordering the northeast of Asia are greatly influenced 

 by the width and depth of the straits. The basin of the Sea of Japan is separated 

 from the Pacific by shallow straits (not deeper than 130 m) ; its depths, how- 

 ever, are well aerated, and its geological past has left a deep imprint on its 

 fauna. The straits connecting the Sea of Okhotsk with the Ocean are deep ; 

 they fall short of the greatest depth of the Sea by only 1,350 m (Table 283). 

 The huge masses of the deep waters of the Sea of Okhotsk suffer, however, 

 from a pronounced shortage of oxygen. The straits leading into the Bering 

 Sea offer little impediment to the exchange of its waters with those of the 

 Ocean, and therefore the Sea of Okhotsk, situated to the south of the Bering 

 Sea, has a much more severe climate. 



The present bottom topography of the Far Eastern Seas is characterized 

 by a small shelf and a large zone of great depths. The areas of the three zones 

 (the shelf, the bathyal and the abyssal) are about equal (Fig. 323). The three 

 Seas, however, differ greatly in this respect. The Sea of Japan has a small 

 shelf, and the abyssal zone is predominant in its bottom topgraphy. The Sea 

 of Okhotsk has a fairly limited abyssal zone, and its bathyal zone is greatly 

 developed, whereas the Bering Sea has an extremely limited bathyal zone and 

 a large shelf in its northeastern part. Its shelf and the abyssal zone occupy 

 practically equal areas (forming about 90 per cent of the total area of the S ea) 



