Equilibrium simulation and driving factors of dissolved oxygen in a shallow eutrophic Inner Mongolian lake (UL) during open-water period

Water quality monitoring buoy installed in the center of the eutrophic shallow lake Ulansuhai was used to explore the dissolved oxygen balance. A revised dissolved oxygen model for shallow eutrophic lakes was applied to identify trends in the lake's dissolved oxygen content during the non-frozen period and determine the equilibrium relationship of dissolved oxygen in the water body. The coefficient of determination and the Nash efficiency of the model proved the feasibility of the model. The main drivers affecting the dissolved oxygen balance of the lake were photosynthesis, aeration and the lateral movements of oxygen rich water, which accounted for 49.28, 14.72 and 36%, respectively, whereas respiration and sediment oxygen consumption, on the other hand, accounted for 1.56 and 98.44%, respectively. These findings suggest that photosynthesis and sediment oxygen consumption dominate the dissolved oxygen balance in eutrophic shallow lakes. A trend analysis of the average oxygen production and consumption rates indicated a maximum of 0.22 mg/L center dot h for photosynthesis and 0.20 mg/L center dot h for sediment oxygen consumption. A correlation analysis showed that water temperature was involved in changing the dissolved oxygen level of the lake mainly by affecting the oxygen consumption process. ; Peer reviewed