Growth of microcystin-producing cyanobacteria in Lake Okeechobee (Florida, USA) and surrounding waters has resulted in adverse health impacts for humans and endangered species, as well as significant economic losses. As these issues worsen, there is growing pressure for efficacious solutions to rapidly mitigate harmful algal blooms (HABs) and protect critical freshwater resources. Applications of USEPA-registered algaecides as management tactics meet many decision-making criteria often required by water resource managers (e.g., effective, scalable, selective), but have not yet been evaluated on a large scale within the Lake Okeechobee waterway. This study was conducted to bolster the peer-reviewed database for available management tactics against microcystin-producing cyanobacteria in waters of this region. Laboratory-scale experiments can be conducted first to minimize uncertainty at larger scales and improve confidence in decision-making. In this study, samples containing microcystin-producing cyanobacteria collected from Lake Okeechobee were exposed to several USEPA-registered algaecides in laboratory toxicity experiments. Responses of target cyanobacteria were measured 3 days after treatment (DAT) in terms of cell density, chlorophyll-a concentrations, and phycocyanin concentrations. Based on responses of the cyanobacteria, minimum effective exposure concentrations were identified for each algaecide. Microcystin release (i.e. proportion of total microcystins in the aqueous phase) was measured and compared 1 DAT among effective exposures. Total microcystin concentrations were measured in effective treatments at 1, 4, and 9 DAT to discern potential for microcystin persistence following exposures to the effective formulations and exposure concentrations. Overall, several formulations including GreenClean Liquid® 5.0, GreenClean Liquid® 5.0 combined with Hydrothol® 191, and the copper-based algaecides evaluated (Algimycin® PWF, Argos, Captain® XTR, Cutrine® Ultra, and SeClear®) achieved significant and similar effects on target cyanobacteria. The chelated copper-based formulations (Algimycin® PWF, Argos, Captain® XTR, and Cutrine® Ultra) resulted in relatively less microcystin release 1 DAT and lesser total microcystin concentrations 4 DAT. At 9 DAT, total microcystin concentrations were significantly lower than in untreated controls in all treatments evaluated. These results provide the necessary comparative performance data for preliminary decision-making and designing additional studies at larger scales. Importantly, the comparative toxicity data and approach provided in this study demonstrate the initial steps for development of site-specific management strategies for Lake Okeechobee and other areas impacted by harmful algal blooms with large spatial and temporal scales.

奥基乔比湖（美国佛罗里达州）和周围水域中产生微囊藻毒素的蓝细菌的生长已对人类和濒危物种造成不利的健康影响，并造成重大的经济损失。随着这些问题的恶化，有效解决方案的压力越来越大，它们需要迅速减轻有害藻华（HAB）并保护关键的淡水资源。以USEPA注册的除藻剂作为管理策略的应用符合水资源管理人员通常要求的许多决策标准（例如，有效，可扩展，选择性），但尚未在奥基乔比湖水道内得到大规模评估。进行这项研究是为了支持同行评审的数据库，以获取针对该地区水域中产生微囊藻毒素的蓝细菌的可用管理策略。首先可以进行实验室规模的实验，以最大程度地减少不确定性并提高决策的信心。在这项研究中，从奥基乔比湖收集的含有产生微囊藻毒素的蓝细菌的样品在实验室毒性实验中暴露于几种USEPA注册的除藻剂。处理后3天（DAT），根据细胞密度，叶绿素-一种浓度和藻蓝蛋白浓度。根据蓝细菌的反应，确定每种除藻剂的最低有效暴露浓度。测量了微囊藻毒素的释放量（即水相中微囊藻毒素总量的比例），并比较了有效暴露中的1 DAT。在1、4、9 DAT的有效治疗中测量总微囊藻毒素浓度，以识别暴露于有效制剂和浓度后微囊藻毒素持续存在的潜力。总体而言，包括GreenCleanLiquid®5.0，GreenCleanLiquid®5.0与Hydrothol®191组合以及经评估的铜基除藻剂（Algimycin®PWF，Argos，Captain®XTR，Cutrine®Ultra和SeClear®）的几种配方均取得了显着和相似的效果。对目标蓝细菌的影响。螯合的铜基配方（Algimycin®PWF，Argos，Captain®XTR和Cutrine®Ultra）产生的微囊藻毒素释放量相对较少（1 DAT），而总微囊藻毒素浓度较低（4 DAT）。在DAT为9时，在所有评估的处理中，总微囊藻毒素浓度均显着低于未处理的对照组。这些结果为初步决策和设计更大规模的附加研究提供了必要的比较性能数据。重要的是，本研究提供的比较毒性数据和方法证明了为奥基乔比湖及其他受时空大范围有害藻华侵袭的地区制定针对特定地点的管理策略的初步步骤。和Cutrine®Ultra）产生的微囊藻毒素释放量相对较少（1 DAT），而总的微囊藻毒素浓度较低（4 DAT）。在DAT为9时，在所有评估的处理中，总微囊藻毒素浓度均显着低于未处理的对照组。这些结果为初步决策和设计更大规模的附加研究提供了必要的比较性能数据。重要的是，本研究提供的比较毒性数据和方法证明了为奥基乔比湖及其他受时空大范围有害藻华侵袭的地区制定针对特定地点的管理策略的初步步骤。和Cutrine®Ultra）产生的微囊藻毒素释放量相对较少（1 DAT），而总的微囊藻毒素浓度较低（4 DAT）。在DAT为9时，在所有评估的处理中，总微囊藻毒素浓度均显着低于未处理的对照组。这些结果为初步决策和设计更大规模的附加研究提供了必要的比较性能数据。重要的是，本研究提供的比较毒性数据和方法证明了为奥基乔比湖及其他受时空大范围有害藻华侵袭的地区制定针对特定地点的管理策略的初步步骤。这些结果为初步决策和设计更大规模的附加研究提供了必要的比较性能数据。重要的是，本研究提供的比较毒性数据和方法证明了为奥基乔比湖及其他受时空大范围有害藻华侵袭的地区制定针对特定地点的管理策略的初步步骤。这些结果为初步决策和设计更大规模的附加研究提供了必要的比较性能数据。重要的是，本研究提供的比较毒性数据和方法证明了为奥基乔比湖及其他受时空大范围有害藻华侵袭的地区制定针对特定地点的管理策略的初步步骤。