Diversity of Cyanobacteria and Microalgae in the Shallow Mountain Lake Paučko, Konjuh Mountain

Shallow mountain lakes are highly sensitive to eutrophication. Cyanobacteria and microalgae in planktonic communities are the main producers in lake ecosystems, but stability of its communities is impacted by numerous factors. The aim of this study is to analyze seasonal diversity and community structure of cyanobacteria and microalgae in plankton and periphyton of the lake Paučko, physical and chemical properties of water and evaluate trophic status. The mountain lake Paučko is the shallow natural lake in Protected landscape Konjuh in northeastern Bosnia and Herzegovina. Sampling of net – phytoplankton, periphyton and water for physical and chemical analysis was caried in two seasons in 2018. Light microscopes and immersion objective (magnification 1000x) were used for the identification and quantification of microalgae. Non metric multimensional scaling and Simper analysis were used to describe communities in periphytic and planktic samples. In total, 70 taxa were identified. The most numerous were Bacillariophyta with 52, and Chlorophyta with 7 taxa. Seasonal dynamics in plankton communities were observed in the direction of shift of abundant Cyclotella meneghiniana, Dinobryon divergens, Peridinum cinctum and Ankistrodesmus fusiformus in spring season to Rabdoderma lineare and Pantocsekiella comensis in summer sampling season. Physical and chemical analysis of water revealed high values of total phosphorus, which correspond to the evaluated meso to eutrophic status of the lake calculated by Rott Trophic Index. The lake Paučko is under high pressure caused by the influx and retention of nutrients, which makes it susceptible to eutrophication. The results of the study provide the first insight into the diversity of cyanobacteria and microalgae for this lake and can be useful in planning of restoration measures in the context of ecological monitoring.