Interconnection of bacterial and phytoplanktonic communities with hydrochemical parameters from ice and under-ice water in coastal zone of Lake Baikal

Abstract The role of light pollution in aquatic ecosystems functioning has increased in recent times. In addition, the effect of such pollution has mostly been studied in coastal marine ecosystems, leaving freshwater ecosystems much less studied. In the p resent work, we investigated the effect of light pollution on the coastal zone of the ancient Lake Baikal ecosystem. Both a laboratory experiment and field research were conducted. The results of the experiment showed the presence of statistically significant differences (р =0.009) between fish feeding on amphipods with and without daylight conditions, while there were no such differences between daylight and artificial light conditions. At the same time, video recordings revealed both a low number of specimens and a low species diversity of amphipods near to the village with a developed system of street lights, while in the village with a nearly nonexistent light system, the species diversity and a number of amphipods were much higher. One plausible explanation for such influence of light pollution on the quality and quantity of Baikal amphipod fauna might be the sum of several factors such as high water transparency and daily vertical migrations of amphipods.

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Influence of breeze circulation on variations of ground ozone and other small gas impurities near the coastal zone of Lake Baikal

25th International Symposium on Atmospheric and Ocean Optics: Atmospheric Physics ◽

10.1117/12.2539199 ◽

2019 ◽

Cited By ~ 1

Author(s):

Alexander S. Zayakhanov ◽

Galina S. Zhamsueva ◽

Vadim V. Tsydypov ◽

Tumen S. Balzhanov

Keyword(s):

Coastal Zone ◽

Lake Baikal ◽

Breeze Circulation

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A new similarity model for the stratified under-ice boundary layer in lakes and its application to ice-covered Lake Baikal

10.5194/egusphere-egu2020-7478 ◽

2020 ◽

Author(s):

Georgiy Kirillin ◽

Ilya Aslamov ◽

Nikolai Granin ◽

Roman Zdorovennov

Keyword(s):

Boundary Layer ◽

Heat Flux ◽

Lake Baikal ◽

Strong Dependence ◽

Shear Velocity ◽

Ice Cover ◽

Heat Fluxes ◽

Solid Boundary ◽

Buoyancy Frequency ◽

Ice Water

<p>Seasonal ice cover on lakes and polar seas creates seasonally developing boundary layer at the ice base with specific features: fixed temperature at the solid boundary and stable density stratification beneath. Turbulent transport in the boundary layer determines the ice growth and melting conditions at the ice-water interface, especially in large lakes and marginal seas, where large-scale water circulation can produce highly variable mixing conditions. Since the boundary mixing under ice is difficult to measure, existing models of ice cover dynamics usually neglect or parameterize it in a very simplistic form. We propose a model of the turbulent energy budget in the stably stratified boundary layer under ice, based on the length scale incorporating the dissipation rate and the buoyancy frequency (Dougherty-Ozmidov scaling). The model was verified on fine-scale measurements in Lake Baikal and demonstrated a good agreement with data. The measured ice-water heat fluxes in were among the largest reported in lakes (up to 40&#8201;W&#8201;m<sup>&#8722;2</sup>) and scaled well against the proposed relationship. The model yields a scaling relationship for the ice-water heat flux as a function of the shear velocity squared that suggests the traditional bulk parameterizations may significantly underestimate the ice-water heat flux, especially at strong under-ice current velocities. The ultimate result consists in a strong dependence of the water-ice heat flux on the shear velocity under ice.&#160;</p>

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Turbulence in the stratified boundary layer under ice: observations from Lake Baikal and a new similarity model

Hydrology and Earth System Sciences ◽

10.5194/hess-24-1691-2020 ◽

2020 ◽

Vol 24 (4) ◽

pp. 1691-1708 ◽

Cited By ~ 2

Author(s):

Georgiy Kirillin ◽

Ilya Aslamov ◽

Vladimir Kozlov ◽

Roman Zdorovennov ◽

Nikolai Granin

Keyword(s):

Boundary Layer ◽

Heat Flux ◽

Lake Baikal ◽

Dissipation Rate ◽

Large Scale ◽

Shear Velocity ◽

Ice Cover ◽

Solid Boundary ◽

Buoyancy Frequency ◽

Ice Water

Abstract. Seasonal ice cover on lakes and polar seas creates seasonally developing boundary layer at the ice base with specific features: fixed temperature at the solid boundary and stable density stratification beneath. Turbulent transport in the boundary layer determines the ice growth and melting conditions at the ice–water interface, especially in large lakes and marginal seas, where large-scale water circulation can produce highly variable mixing conditions. Since the boundary mixing under ice is difficult to measure, existing models of ice cover dynamics usually neglect or parameterize it in a very simplistic form. We present the first detailed observations on mixing under ice of Lake Baikal, obtained with the help of advanced acoustic methods. The dissipation rate of the turbulent kinetic energy (TKE) was derived from correlations (structure functions) of current velocities within the boundary layer. The range of the dissipation rate variability covered 2 orders of magnitude, demonstrating strongly turbulent conditions. Intensity of mixing was closely connected to the mean speeds of the large-scale under-ice currents. Mixing developed on the background of stable density (temperature) stratification, which affected the vertical structure of the boundary layer. To account for stratification effects, we propose a model of the turbulent energy budget based on the length scale incorporating the dissipation rate and the buoyancy frequency (Dougherty–Ozmidov scaling). The model agrees well with the observations and yields a scaling relationship for the ice–water heat flux as a function of the shear velocity squared. The ice–water heat fluxes in the field were the largest among all reported in lakes (up to 40 W m−2) and scaled well against the proposed relationship. The ultimate finding is that of a strong dependence of the water–ice heat flux on the shear velocity under ice. The result suggests large errors in the heat flux estimations when the traditional “bulk” approach is applied to stratified boundary layers. It also implies that under-ice currents may have much stronger effect on the ice melt than estimated by traditional models.

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