Due to eutrophication, many lakes require periodic management and restoration, which becomes unpredictable due to internal nutrient loading. To provide better lake management and restoration strategies, a deterministic, one-dimensional water quality model MINLAKE2020 was modified from daily MINLAKE2012 by incorporating chlorophyll-a, nutrients, and biochemical oxygen demand models into the regional year-around temperature and dissolved oxygen (DO) model. MINLAKE2020 was applied to six lakes (varying depth and trophic status) in Minnesota focusing on studying the internal nutrient dynamics. The average root-mean-square errors (RMSEs) of simulated water temperature and DO in six lakes are 1.51 °C and 2.33 mg/L, respectively, when compared with profile data over 2–4 years. The average RMSE of DO simulation decreased by 24.2% when compared to the MINLAKE2012 model. The internal nutrient dynamics was studied by analyzing time series of phosphorus, chlorophyll-a, and DO over several years and by performing a sensitivity analysis of model parameters. A long-term simulation (20 years) of Lake Elmo shows that the simulated phosphorus release from sediment under the anoxic condition results in surface phosphorus increase, which matches with the observed trends. An average internal phosphorus loading increase of 92.3 kg/year increased the average daily phosphorus concentration by 0.0087 mg/L.

中文翻译：

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模拟湖泊中的营养物质和浮游植物动力学：模型开发和应用

由于富营养化，许多湖泊需要定期管理和恢复，由于内部养分负荷而变得不可预测。为了提供更好的湖泊管理和恢复策略，确定性的一维水质模型 MINLAKE2020 从每日 MINLAKE2012 修改而来，将叶绿素 a、营养素和生化需​​氧量模型纳入区域全年温度和溶解氧 (DO)模型。MINLAKE2020 应用于明尼苏达州的六个湖泊（不同深度和营养状态），重点研究内部营养动态。与 2-4 年的剖面数据相比，六个湖泊的模拟水温和 DO 的平均均方根误差 (RMSE) 分别为 1.51 °C 和 2.33 mg/L。DO 模拟的平均 RMSE 降低了 24。与 MINLAKE2012 模型相比为 2%。通过分析多年来磷、叶绿素 a 和 DO 的时间序列并对模型参数进行敏感性分析，研究了内部养分动态。埃尔莫湖的长期模拟（20 年）表明，在缺氧条件下模拟的沉积物磷释放导致地表磷增加，这与观察到的趋势相符。平均内部磷负荷增加 92.3 公斤/年，平均每日磷浓度增加了 0.0087 毫克/升。埃尔莫湖的长期模拟（20 年）表明，在缺氧条件下模拟的沉积物磷释放导致地表磷增加，这与观察到的趋势相符。平均内部磷负荷增加 92.3 公斤/年，平均每日磷浓度增加了 0.0087 毫克/升。埃尔莫湖的长期模拟（20 年）表明，在缺氧条件下模拟的沉积物磷释放导致地表磷增加，这与观察到的趋势相符。平均内部磷负荷增加 92.3 公斤/年，平均每日磷浓度增加了 0.0087 毫克/升。