As producers of biomass, cyanobacteria are a major part of the phytoplankton in a large number of water basins. Due to the cyanobacterial blooms and cyanotoxins produced, these organisms are recognized as a threat and ecological risk for water bodies. Released cyanotoxins may cause death of many organisms including birds and fish. Vaya Lake is the largest natural lake in Bulgaria. It is located on the Via Pontica migration route of birds between Europe and Africa. Since 2003, the lake has been declared as a "Wetland of international importance” under the Ramsar Convention. According to the literature data from 2002-2006, the Lake is defined as highly eutrophied due to strong anthropogenic pressure, but regular monitoring of the cyanobacterial blooms and presence of cyanotoxins after this period is missing. Taking into account the importance of this unique, protected ecosystem, our aim was to make a complete ecological assessment of the present state of Lake Vaya by using the phytoplankton, with an emphasis on cyanobacterial blooms and the presence of cyanotoxins. As results of the study, we 1) characterized the phytoplankton composition qualitatively and quantitatively; 2) evaluated the ecological status of the western and eastern part of the Lake; 3) identified the potential producers of cyanotoxins; 4) observed cyanobacterial blooms and discussed the influence of macrophytes on their spread; 5) measured the concentrations of the cyanotoxins MCs, CYL and STXs in water samples from both parts of the Lake. Our results indicated the need for continued observation of cyanobacterial composition, blooming and the presence of cyanotoxins in Lake Vaya.

中文翻译：

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浮游植物的组成以蓝藻及其毒素为重点，可作为指示Vaya湖（保加利亚）生态状况的标志，这是Via Pontica迁移路线的一部分

作为生物质的生产者，蓝藻是许多流域中浮游植物的主要组成部分。由于产生了蓝藻水华和蓝藻毒素，这些生物被认为是对水体的威胁和生态风险。释放的氰毒素可能导致许多生物死亡，包括鸟类和鱼类。Vaya湖是保加利亚最大的天然湖泊。它位于鸟类在欧洲和非洲之间的Via Pontica迁徙路线上。自2003年以来，根据《拉姆萨尔公约》，该湖被宣布为“具有国际重要意义的湿地”，根据2002年至2006年的文献数据，由于人为压力强，该湖被定义为富营养化，但需定期监测蓝藻这段时间之后，花开并没有蓝藻毒素存在。考虑到这个独特的受保护生态系统的重要性，我们的目标是通过使用浮游植物对瓦亚湖的现状进行完整的生态评估，重点是蓝藻水华和蓝藻毒素的存在。作为研究结果，我们1）定性和定量地表征了浮游植物的组成；2）评估了湖的西部和东部的生态状况；3）确定了潜在的氰毒素生产者；4）观察蓝藻水华并讨论大型植物对其传播的影响；5）测量了湖两岸水样中氰毒素MC，CYL和STX的浓度。我们的结果表明，需要继续观察瓦亚湖中的蓝细菌组成，开花和蓝藻毒素的存在。