Abstract

The trophic state and water quality of Lake Onegо have been assessed under climate warming and changes in anthropogenic load over the past 30 years. The water body retains its natural oligotrophic state during the summer stratification according to the concentration of Chl a. A small amount of readily mineralizable organic matter in water determines the low level of development of saprophytic bacteria, corresponding to xenosaprobic and β-oligosaprobic waters. Only Kondopogskaya Bay in Lake Onego is characterized by a higher trophic level (mesotrophic) and water saprobity (β-mesosaprobic) due to pollution by wastewater from the PPM and waste from trout farms. The local bloom of cyanobacteria in the open area of the lake was observed during the anomalous heating of the epilimnion in the summer of 2022 for the first time in the 50-year history of research. The increase in the concentration of humic substances in the water of the bays as a result of climate warming at this stage did not lead to a change in the level of saprophytic bacteria.

中文翻译：

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奥涅戈湖当前的营养状况和水质

摘要

奥涅戈湖的营养状况和水质已根据过去 30 年的气候变暖和人为负荷变化进行了评估。根据叶绿素浓度a，水体在夏季分层期间保持其自然贫营养状态。水中的少量易矿化有机物决定了腐生细菌的低水平发育，对应于异腐菌和β-寡腐菌水。由于受到 PPM 废水和鳟鱼养殖场废物的污染，只有奥涅戈湖的 Kondopogskaya 湾具有较高的营养级（中营养级）和水体腐败性（β-中腐级）。 2022年夏季，湖水异常升温期间，在50年的研究史上首次观察到了湖中开阔区域蓝藻的局部繁殖。现阶段气候变暖导致海湾水中腐殖质浓度增加，但并未导致腐生细菌水平发生变化。