The work is devoted to the structure and functioning of biocenoses in the open ocean water column. Based on the distribution of several hundred plankton species for the water column, the concepts of "population," "station," "biocenosis," "biotope" are determined for the first time, a new definition of the species range is given. In detail and specifically for all oceans, stations, populations, biotopes and biocenoses are described and their typing is given. A new biogeographic division of the World Ocean is presented. A holistic theory of life in a mobile biotope is proposed and a comparison is made with a fixed habitat on the bottom and on land. The monograph is designed for scientists in the field of general ecology and biogeography, oceanology, hydrobiology and ichthyology, workers in the fishing industry, graduate students and biophak students.