Use of Hydrooptical Characteristics in Monitoring the Status of the Reservoir Ecosystem

Abstract

Use of hydrooptical characteristics in monitoring the reservoir ecosystem is investigated. Two basic characteristics which are most commonly used for purposes of ecological monitoring having regard to information content and ease of measurements are considered: the beam attenuation coefficient ε, the and Secchi disc depth Z_SD. Theoretical analysis shows a relationship of ε and Z_SD with content of suspended matter and chlorophyll in water. It is concluded, however, that correct theoretical calculations of the content of these substances is not possible to correctly calculate these substances in a theoretical way from e and Z_SD. In this context, empirical relationships of suspended matter and chlorophyll concentrations with hydrooptical characteristics are used for monitoring purposes. These relationships are regional in character, which is accounted for by the regional composition of suspended matter and by the intracellular concentration of pigments in algae. Examples of empirical relationships of suspended matter and chlorophyll concentrations with the beam attenuation coefficient and the Secchi depth in Lake Baikal, the Black Bea and the tropical waters of the Atlantic waters are given. It is found that in addition to the content of suspended matter and chlorophyll in reservoirs, it is important, for biological purposes, to know the thickness of the euphotic layer for total quantum irradiation H_euph.quant. Examples of the determination of the euphotic layer thickness for total quantum irradiation H_euph.quant. using Secchi depth for different reservoirs are provided.