Abstract

A study of the horizontal and vertical distribution of phytoplankton in Lake Sevan was conducted in mid-July 2018 during the maximum Cyanoprokaryota blooms. The summer biomass of algae in the pelagic zone of the lake corresponded to values of mesatrophic waters. The Cyanoprokaryota biomass in Lake Sevan has horizontal and vertical heterogeneity and is related to the depth, morphometry of the lake parts, distribution of currents, transparency, temperature, and biomass of Cladocera. The specific number of phytoplankton species and water transparency decreases in areas where water blooms occur. The following factors contribute to the increase in the average phytoplankton biomass when compared to 2013–2017: (1) increased water temperature, (2) weakening of zooplankton grazing pressure due to the disappearance of Daphnia magna, and (3) increased phosphorus load due to increased contribution of D. longispina and Diaphanosoma lacustris to the zooplankton biomass.

中文翻译：

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夏季蓝藻原水生藻在高山塞凡湖（亚美尼亚）中浮游植物的水平和垂直分布

摘要

2018年7月中旬，在蓝藻原花最大开花期间，对塞凡湖浮游植物的水平和垂直分布进行了研究。湖中上层带藻类的夏季生物量与中营养水的值相对应。塞凡湖的蓝原核生物量具有水平和垂直的异质性，与深度，湖泊部分的形态，水流的分布，透明度，温度和克拉多菌的生物量有关。在发生水华的地区，浮游植物的特定数量和水透明度降低。与2013-2017年相比，以下因素促成浮游植物平均生物量的增加：（1）水温升高，（2）由于大型蚤（Daphnia magna）的消失，浮游动物的放牧压力减弱。（3）由于D. longispina和Diaphanosoma lacustris对浮游动物生物量的贡献增加，磷负荷增加。