Abstract Long-term changes in hydrochemistry and community structure of phytoplankton and macrophytes were analyzed in the Sestroretskiy Razliv reservoir (northwestern Russia). The average content of total phosphorus (TP) in May–October increased from 73 μg P l−1 in 1980 to 163 μg P l−1 in 2000. A significant increase in average chlorophyll a content from 16.6 μg l−1 in 1980 to 84.7 μg l−1 in 2000 and a shift in phytoplankton composition to the dominance of cyanobacteria over diatoms indicated a change in the trophic status of the reservoir from meso-eutrophic to hypertrophic. In 2016 and 2018, average TP was 96 and 101 μg P l−1, respectively. The average content of chlorophyll a was 43.6 μg l−1 in 2016 and 66.6 μg l−1 in warmer 2018, indicating persistent eutrophic conditions. Diatoms dominated both in 2016 and 2018, especially in 2016 characterized by unfavorable weather conditions. Cyanobacteria were more abundant in 2018 with higher summer temperatures. The decline of the total area covered by aquatic vegetation from 157 ha in 1980 to 76 ha in 2016 likely resulted from an increase in phytoplankton biomass and water turbidity. Based on the results of our observations, in addition to further reduction in nutrient loading, biomanipulation by introducing predatory fish as a restoration measure was proposed to improve the ecological status of the reservoir.

中文翻译：

---

富营养化浅水库浮游植物和大型植物群落的长期变化及其恢复前景

摘要 对Sestroretskiy Razliv 水库（俄罗斯西北部）中浮游植物和大型植物的水化学和群落结构的长期变化进行了分析。5-10月全磷（TP）平均含量从1980年的73 μg P l-1增加到2000年的163 μg P l-1。平均叶绿素a含量从1980年的16.6 μg l-1显着增加到2000 年为 84.7 μg l-1，浮游植物组成转变为蓝藻在硅藻上占主导地位，表明水库的营养状态从中富营养变为肥厚。2016 年和 2018 年，平均 TP 分别为 96 和 101 μg P l-1。2016 年叶绿素 a 的平均含量为 43.6 μg l-1，2018 年温暖时为 66.6 μg l-1，表明富营养化条件持续存在。硅藻在 2016 年和 2018 年均占主导地位，尤其是在 2016 年，天气条件不利。2018 年，随着夏季温度的升高，蓝藻更加丰富。水生植被覆盖的总面积从 1980 年的 157 公顷下降到 2016 年的 76 公顷，可能是由于浮游植物生物量和水浊度的增加。根据我们的观察结果，除了进一步减少养分负荷外，还提出了通过引入捕食性鱼类的生物操纵作为恢复措施，以改善水库的生态状况。