Peculiarities of Thermal Regime Formation of Near-Bottom Lake Water

Abstract

Our paper presents data on the annual course of the temperatures of surface sediments in deep bottom areas of a lake that has been assigned a "moderately-warm" designation. It is shown that the highest temperatures of those sediments are reached in autumn when near-bottom waters are involved with the processes of the gravitational mixing of the water column. Mixing conditions of the water column were estimated using additional information on the vertical profiles of standard water variables (pH, oxygen concentration, and conductivity). It is shown that depending on the amount of heat stored in the sediments of the deep bottom areas and the thermodynamic processes of its redistribution, the lake may be designated "super-warm" or "moderately-warm. " This implies that existing thermal classification of lakes is too formal and does not account for the complexity of thermodynamic processes of heat redistribution. Measurement data is evidence of the implication of the inflows from the bottom-feeding sources in the formation of the highly mineralized near-bottom water layer in those bottom areas.

Peculiarities of the Vertical Thermal Regime of Lake Tapeliai

“…The sediment layer forms a separate, important, independent part of Lake Tapeliai. We support numerous authors who devote special attention to sediments and even suggest distinguishing a separate group of lakes with sediments (see, e.g., [24] and references there).…”

“…Complex bathymetric measurements of Lake Tapeliai associated with sediments have been published [24]. In the present work, we will use at the same time our obtained experimental results concerning the temperature dependence on depth.…”

Mathematical Modelling as a Tool for the Assessment of Impact of Thermodynamics on the Algal Growth in Dam Reservoirs – Case Study of the Goczalkowice Reservoir

“…Changes in water temperature in lakes and reservoirs is one of the key processes affecting the spatial and temporal distribution of chemical compounds and biological elements such as plankton and fish [Elci 2008;Genova et al 2010;Yu et al 2010]. The water temperature depends on geographic conditions (e.g., bathymetry, elevation, latitude and interactions with groundwater) and seasonal changes in meteorological conditions (e.g., solar radiation, cloud cover, wind speed and direction) [Lee et al 2013;Tuan et al 2009;Tarasiuk et al 2015]. The temperaturebiochemistry interdependences are often bidirectional, and the concentration of suspended solids or plankton inhibiting the penetration of solar radiation, for example, may impact the water temperature [Kumagai et al 2000;Mazumder et al 1990].…”