THE BLACK SEA 381 



A more profound study of the invertebrate fauna of the Black Sea was 

 begun by the end of the 'sixties with the investigations of V. Tchernjavsky 

 (mainly of the crustaceans). 



In 1868 V. Uljanin, who later became the first director of the Sevastopol 

 Biological Station founded in Odessa in 1871-72 and was transferred to 

 Sevastopol in 1879, began his investigations of the Black Sea. As a result of 

 his work Uljanin produced for the Black Sea a list containing 380 species of 

 animals and proceeded to a zoogeographical appraisal of the Black Sea fauna 

 which remains basically correct to this day. The Black Sea fauna is mainly a 

 greatly impoverished Mediterranean fauna which has acquired only a feebly 

 marked independent character, and which shares some unimportant features 

 with the Aral-Caspian fauna. 



On the initiative of our greatest geologist, N. Andrussov, a composite 

 sounding expedition worked in the Black Sea, which included Andrussov and 

 O. Ostroumov, with the hydrologist I. Spindler as its director. During this 

 expedition the contamination of the deep layers of the Sea by hydrogen sul- 

 phide and the absence of life there was discovered for the first time. Later the 

 work of Ostroumov in 1892-94 in the Bosporus, the Sea of Marmora and 

 in some parts of the Black Sea and the Sea of Azov was of great importance. 

 Westward of the Bosporus were found shells of Caspian molluscs in a semi- 

 fossil state, an indication that the Sea of Marmora had formed part of the 

 Pontic basin. On the other hand, Ostroumov showed that the fauna of the 

 eastern part of the Sea of Azov and of the river mouths and inlets of the Black 

 Sea bore the greatest resemblance to that of the Caspian Sea. 



Thus the main ideas on the Black Sea fauna, its relation to the Caspian 

 and Mediterranean faunas, the history of its origin and development, were 

 formed by the beginning of the present century. The work of V. Sovinsky 

 (1902) who summed up all the information collected earlier on the Black Sea, 

 is an excellent conclusion to this stage of the investigation of its fauna and 

 zoogeography. 



Second period 



In the year of the publication of Sovinsky's monograph, S. Zernov began his 

 work on the Black Sea as the Director of the Sevastopol Biological Station ; 

 the second period of the investigation of the Black Sea fauna is linked with 

 his name. This ecological qualitative biocoenotic stage is characterized by a 

 comprehensive investigation of the distribution of life in the coastal zone and 

 of the main factors determining it (sea-bed, temperature, swell, etc.). Zer- 

 nov's ten years of work were concluded by the writing of his widely known 

 monograph On the Study of Life in the Black Sea (1913). 



Third period 



The great development of oceanographic investigation during the Soviet 

 epoch has also had its effect on the study of the Black Sea. Several research 

 institutes have been created and a series of expeditions has worked in the Sea. 

 Among the expeditions the most important were : the Azov and Black Seas 



