О.Б. Акулова, В.И. Букатый, К.В. Марусин.
Пространственная изменчивость гидрооптических характеристик Телецкого озера
Keywords: coefficients of light attenuation and absorption; Secchi disk transparency; dissolved organic matter; yellow substance; chlorophyll; suspended matter
The paper presents the results of studies of the spatial distribution of primary hydrooptical characteristics, in particular, light attenuation ε by lake water at a wavelength of 550 nm, light absorption by yellow substance κys at a wavelength of 450 nm, and relative transparency Z measured with Secchi disk. The data were obtained in summer 2018 during field surveys of the Laboratory of Hydrology and Geoinformatics of IWEP SB RAS on Lake Teletskoye (Altai Mountains). The values of ε for the study period were within 0.4–2.3 m–1, κys – 0.5–3.0 m–1 (calculated at natural logarithm base), Z – 1.0–11.7 m. The yellow substance concentration calculated by the measured transmittance of yellow substance, varied within 2.6–14.1 g/m3, the chlorophyll concentration – 0.4–1.8 mg/m3. According to the data from the chemical analytical center of IWEP, the average concentration of total phosphorus in the surface layer of the lake during the study period was 10.8 mg/m3, total nitrogen – 731.3 mg/m3, total carbon – 3.35∙103 mg/m3. Besides, the relative spectral contribution of major optically active components of lake water (purewater, yellow substance,suspended matter and chlorophyll) to light attenuation across the lake water area was estimated. It was found that yellow substance makes the largest contribution to ε at all sampling points (22) of the lake. It is shown that the optical structure of the lake and the spatial variability of hydro-optical characteristics are closely related to the hydrological regime of the lake, meteorological conditions in the region and various optically active water components, whose concentration changes both in time and space under the influence of processes inside the lake in association with the catchment. The analysis of the spatial distribution of the indices of light attenuation and absorption by yellow substance in the lake water showed that Lake Teletskoye stands out not only for its hydro-optical characteristics, but also its hydrobiological and hydrochemical characteristics. Hence, the total light attenuation by lake water can serve as an objective marker of the hydrophysical structure of the lake and its ecological state.
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