The researchers studied Lake Changhu in China to understand how pollution levels and nutrient capacity changed after removing pen aquaculture from the lake. They analyzed different areas of the lake over several years. In 2017, levels of nitrogen, organic matter, and other pollutants were highest. Sediment in the lake showed increased nitrogen and phosphorus content from 2013 to 2018. The lake's eutrophication level peaked in 2017. The calculations indicated that in 2015, the lake had excess nitrogen and phosphorus, but by 2018, it was closer to target water quality levels. This study gives important insights into how the lake's condition evolved over time, providing valuable information for managing water quality and ecosystem health.