Cyanobacteria are known to produce a wide variety of bioactive, toxic secondary metabolites generally described as hepatotoxins, neurotoxins, cytotoxins, or dermatoxins. In Brazil, the regular monitoring of cyanobacterial toxins has intensified after the death of 65 patients in a hemodialysis clinic in Caruaru in the state of Pernambuco due to microcystin exposure. The primary objective of this study was to use multivariate statistics that incorporated environmental parameters (both biotic and abiotic) to forecast blooms of cyanobacteria and their toxic secondary metabolites in 20 drinking water reservoirs managed by the Water Treatment Company of Ceará (CAGECE) in the semi-arid region of Ceará, Brazil. Across four years (January 2013 to January 2017), 114 different phytoplankton taxa were identified, including 24 cyanobacterial taxa. In general, Ceará reservoirs were dominated by cyanobacteria due to eutrophication but also because of the dry and warm climate found throughout the region. Interestingly, specific cyanobacterial taxa were influenced by different biotic and abiotic factors. For example, nitrogen-to-phosphorus (N:P) and evaporation were positively related to saxitoxin-producing taxa, especially Raphidiopsis raciborskii, while temperature, electrical conductivity, total phosphorus, and transparency (measured as Secchi depth) were positively associated with microcystin-producing taxa, such as Microcystis aeruginosa. Climate forecasts predict higher evaporation and temperatures in the semi-arid Ceará region, which will likely magnify droughts and water scarcity as well as promote toxic cyanobacterial blooms in reservoirs in the future. Therefore, understanding the factors associated with algal blooms dominated by specific taxa is paramount for water resource management.

众所周知，蓝细菌会产生多种生物活性，有毒的次级代谢产物，通常被描述为肝毒素，神经毒素，细胞毒素或皮肤毒素。在巴西，由于微囊藻毒素暴露，在伯南布哥州卡鲁阿鲁的血液透析诊所死亡的65名患者死亡后，加强了对蓝细菌毒素的常规监测。这项研究的主要目的是利用多变量统计数据，结合环境参数（生物和非生物参数）来预测由塞阿拉州水处理公司（CAGECE）所管理的20个饮用水水库中的蓝藻繁殖及其有毒次生代谢产物。巴西塞阿拉的干旱地区。在四年（2013年1月至2017年1月）中，确定了114种不同的浮游植物类群，包括24种蓝细菌类群。一般来说，塞阿拉的水库由于富营养化而被蓝细菌所控制，也因为整个地区都处于干燥温暖的气候。有趣的是，特定的蓝细菌类群受不同的生物和非生物因素影响。例如，氮磷（N：P）和蒸发与产生毒素的分类单元呈正相关，特别是Raphidiopsis raciborskii，而温度，电导率，总磷和透明度（以Secchi深度测量）与产生微囊藻毒素的类群（如铜绿微囊藻）呈正相关。气候预测预测，半干旱塞阿拉地区的蒸发量和温度会更高，这可能会加剧干旱和缺水，并在将来促进水库中有毒的蓝细菌繁殖。因此，了解与以特定分类单元为主的藻华有关的因素对于水资源管理至关重要。