Located in the Amur watershed, Lake Kenon is an urban reservoir that hosts recreational and commercial fishery activity. The current status of the lake is connected with the Chita Thermal Power Plant No 1, the basin’s human population, and the density of railways as well as highways within the basin. From the start of the thermal power plant’s operation, the reservoir’s ion composition significantly changed from largely sodium and bicarbonate species to sulfate, bicarbonate, chloride, sodium, calcium, and magnesium chemical species. Additionally, heavy metals have been accumulating in Kenon’s sediment. The results presented in this article are based on field measurements and comparative analysis with previous studies. Primary production was calculated using a light-dark bottle method. During the study period, current evidence corroborated previous investigations that respiration and decomposition rates generally tend to exceed photosynthesis rates. As noted in June 2015, in the cent of the lake where complete mixing occurs, primary production as well as respiration decreases with depth in the water column. With increased warming since August 2015, primary production exceeded respiration in upper layers. Considering the lake’s relatively small area for thermal fluxes (10% of the lake’s surface area), production-respiration processes are within Lake Kenon’s ecological capacities. The observed photosynthesis-respiration ratios from long-term study suggest that the system is resilient to the current anthropogenic load.