Ice cover significantly alters lake ecology, most directly affecting photosynthesis and dissolved oxygen. Accurate, rapid, and continuous in-situ monitoring of key ecological indicators (e.g., dissolved oxygen and chlorophyll) beneath the ice is crucial for protecting river and lake ecosystems. Using high-frequency sensors, the responses of chlorophyll-fluorescence and dissolved oxygen production to irradiance and thermal conditions were explored during the ice-covered period in Lake Wuliangsuhai, a shallow lake in Inner Mongolia, China. Based on the dissolved oxygen results, we estimated net ecosystem production and ecosystem respiration in January-February 2018. Our results showed that the photosynthetic activity of plankton was tightly controlled by photosynthetically active radiation. The penetration depth of photosynthetically active radiation was 90 cm (including 50 cm of ice). Oxygen production occurred mainly within the photic zone, while at greater water depths, oxygen consumption by respiration was greater than its production by photosynthesis. When irradiance was low (<35 mu molm(-2)s(-1)), chlorophyll-fluorescence and irradiance were positively correlated; however, with increasing radiation intensities, chlorophyll-fluorescence decreased, causing a decrease in net ecosystem production. Ecosystem respiration increased in parallel with water temperature. Although the metabolic processes showed a certain degree of lag (3-4 h) relative to the key physical drivers, the rapid changes in chlorophyll-fluorescence and dissolved oxygen concentration clearly proved that photosynthesis was primarily controlled by irradiance. The results reveal the metabolic characteristics of plankton and their physical driving mechanisms during the ice-covered period in shallow lakes, supporting the protection of lake ecosystems in cold and arid regions under climate warming.