Spectral and optical characteristics of dissolved organic matter in meromictic reservoirs of the White Sea coast
Yu.G. Sokolovskaya1, E.D. Krasnova1, D.A. Voronov2, S.V. Patsaeva1
1Lomonosov Moscow State University, Moscow, Russia
2Institute for Information Transmission Problems of the Russian Academy of Sciences (Kharkevich Institute), Moscow, Russia
Keywords: dissolved organic matter (DOM), chromophoric fraction of DOM (CDOM), meromictic reservoir, White Sea, absorption spectra, excitation wavelength, fluorescence quantum yield
Abstract
Natural water contains dissolved organic matter (DOM), which plays an important role in biogeochemical processes and affects the functioning of aquatic ecosystems. The paper analyzes the spectral and luminescent characteristics (optical indices, difference absorption spectra, fluorescence quantum yield, and protein-like fluorescence) of DOM chromophoric fraction (CDOM) in two meromictic reservoirs on the coast of the Kandalaksha Bay of the White Sea, lakes Elovoe and Trekhtzvetnoe based on the results of expeditionary work in 2025. The difference in optical indices in different layers of the reservoirs (the surface fresh layer, the intermediate brackish aerobic layer, the chemocline, and saline bottom hydrogen sulfide zone) and their relationship with hydrochemical parameters are shown. An increase in the quantum yield of CDOM fluorescence in the chemocline of the Lake Elovoe and its decrease in the Lake Trekhtzvetnoe are explained. The results are of importance for ecological monitoring of aquatic ecosystems, as well as for understanding the processes that influence optical characteristics of natural CDOM.
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