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First report about toxic cyanobacterial bloom occurrence in Lake Sevan, Armenia
Author(s) -
Gevorgyan Gor,
Rinke Karsten,
Schultze Martin,
Mamyan Armine,
Kuzmin Anton,
Belykh Olga,
Sorokovikova Ekaterina,
Hayrapetyan Armine,
Hovsepyan Anahit,
Khachikyan Termine,
Aghayan Sargis,
Fedorova Galina,
Krasnopeev Andrey,
Potapov Sergey,
Tikhonova Irina
Publication year - 2020
Publication title -
international review of hydrobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.524
H-Index - 52
eISSN - 1522-2632
pISSN - 1434-2944
DOI - 10.1002/iroh.202002060
Subject(s) - eutrophication , bloom , cyanobacteria , microcystis , aphanizomenon , phytoplankton , environmental science , microcystin , algal bloom , ecology , limnology , biology , anabaena , nutrient , genetics , bacteria
Lake Sevan, Armenia, is the largest freshwater body in the Caucasus region. Cyanobacteria have become increasingly dominant in summer in Lake Sevan, reflecting the eutrophication of the lake and formed a massive bloom event in 2018. These recent observations mark the transition of this previously oligotrophic high mountain lake into an eutrophic lake with scum‐forming cyanobacterial blooms. A bloom of Dolichospermum in July caused a sudden increase in chlorophyll‐ a concentrations up to, on average, 20 µg/L and a strong decrease in water transparency. The cyanobacterial genera Dolichospermum , Aphanizomenon , Anabaena , Cyanobium , and Synechococcus were detected by metagenomic analysis of the lake bacterioplankton. A qualitative and quantitative assessment of peptide‐based secondary metabolites revealed the first detection of cyanotoxins in Lake Sevan. Ten types of microcystin congeners were found in Lake Sevan. The total concentration of microcystins in the phytoplankton varied from 0.34 to 2.49 µg/L. This first record of cyanotoxins in the largest lake in the Caucasus region calls for an urgent need for sustainable nutrient management and a systematic assessment of the ultimate causes that lead to the reoccurrence of scum‐forming Cyanobacteria in this large Alpine lake.