Organic matter and nutrients in Lake Glubokoe (Moscow region, Russia)

Abstract

According to monitoring data from 2019-2025, the current regime of organic matter and nutrient elements in the water of Lake Glubokoe is assessed. The lake is located in a nature reserve within the Moscow region and can be considered as a natural (background) water body for the region (the maximum nitrogen and phosphorus content is several times lower than in the Mozhaysk Reservoir and dozens of times lower than in Lake Beloe in Moscow). Significant interannual variability in the ecological state of the lake was observed: in years with incomplete spring circulation, intensity of summer anoxia is the strongest, and approximately twice as much mineral nitrogen, phosphorus, and colored iron compounds accumulate at the bottom than in other years. At the same time, no monotonous trend is observed in the regime of nutrient elements throughout the history of research, and no long-term changes occur in the organic matter content since the 1960s, when its content in the lake decreased by about half as a result of reclamation work in the catchment area. This calls into question the existing hypothesis of gradual eutrophication of Lake Glubokoe.