Transitional Zones of Freshwater Ecosystems and Principles of the Zoning of the Mouth Areas of Tributaries of Reservoirs

The diversity of transition zones is considered, the main features of ecotones are indicated, and the degree of knowledge of the mouth areas of tributaries of reservoirs is analyzed. A review and analysis of the concept of the estuary region and approaches to zoning the estuarine regions of rivers carrying water to the seas and oceans is provided. Based on the high biological potential, the great role in the life of receiving reservoirs, significant areas and extremely scarce data, the task is set of detailed comprehensive studies of the mixing zones of river and reservoir waters, as well as areas of bordering water bodies, that is, the tributary itself and the reservoir. The principles of identifying different types of zones in the mouth areas of tributaries of lowland reservoirs based on the electrical conductivity of water are presented, and the names of the selected areas are given.