Seasonal changes in the spectral and physico-chemical characteristics of water from the separating lakes of the Kandalaksha Bay of the White Seaтезисы докладаТезисы
Дата последнего поиска статьи во внешних источниках: 21 мая 2019 г.
Аннотация:The work is devoted to the investigation of seasonal variability of spectral characteristics of water
with green sulfur bacteria and its relationship with the distribution of water’s hydrological parameters (temperature, salinity, oxidation-reduction potential, hydrogen index). Water with microorganisms for the optical measurements was sampled from different depths in several lakes (the lagoon on cape Zeleny, Bolshie Khruslomeny, N. Ershovskoye and Trekhtzvetnoe lakes) during the expeditions carried out in the spring and winter in 2016-2018 years. In the work the optical density spectra were measured with the Solar PB 2201 spectrophotometer, and the fluorescence emission and excitation spectra were recorded by the Solar CM2203 luminescence spectrometer. The concentration of photosynthetic pigments of GSB, bacteriochlorophylls, was calculated using the Overmann-Tilzer formula for extracts of natural water samples. During the work it was shown that in the autumn-summer period the concentration of oxygen in the surface layers in all lakes was much higher than in winter. Moreover in September the water samples from different depths showed a much sharper decrease in oxygen concentration in contrast to the March samples from the same lakes. The main result of the work was the demonstration of the fluorescence quenching phenomenon in the upper layers of chemocline, which was more pronounced in summer (July) than in autumn (September) or winter (March). This fact can be explained by the high illumination of the upper layers of chemocline in the autumn-summer period and the presence of oxygen in these layers.
Based on the obtained results, it can be concluded that the separated reservoirs of the White Sea are selfregulating ecosystems whose microbial community is able to adapt to environmental conditions, including changing its physiological state (its photosynthetic activity) depending on external conditions.
