Raphidiopsis raciborskii (formerly Cylindrospermopsis raciborskii) is a freshwater cyanobacterium potentially producing saxitoxins (STX) and cylindrospermopsin. Its ecophysiological versatility enables it to form blooms in the most diverse types of environments, from tropical to temperate, and from relatively pristine to polluted. In Peri Lake, located in the subtropical south of Brazil, growing populations of STX-producing R. raciborskii have been detected since 1994, posing risks to the use of its waters that supply a population of about 100,000 inhabitants. Despite the existence of a monitoring system for the presence and toxicity of cyanobacteria in Peri Lake water, no assessment has been made in the coastal region, downstream of outflowing lake water, thereby potentially making available a toxic biomass to natural and cultivated shellfish populations in the salt water ecosystem. To address this problem, the present study evaluated environmental variables and STX concentration by profiling the outflowing waters between Peri Lake and the adjacent coastal zone. Laboratory experiments were carried out with three strains of R. raciborskii in order to confirm the effect of salinity on STX production and verify if Perna Perna mussels fed with R. raciborskii cultures would absorb and accumulate STX. Results showed that environmental concentrations of STX reach high levels (up to 6.31 µg L⁻¹ STX eq.), especially in the warmer months, reaching the coastal zone. In laboratory tests, it was found that the strains tolerate salinities between 4 and 6 and that salinity influences the production of STX. In addition, mussels fed with R. raciborskii effectively absorb and accumulate STX, even in typically marine salinities (22 to 30), suggesting that R. raciborskii biomass remains available and toxic despite salinity shock. These results draw attention to the ecological and health risk associated with R. raciborskii blooms, both in the lake environment and in the adjacent marine environment, calling attention to the need to improve the monitoring and management systems for water and shellfish toxicity in the region of interest, as well as other places where toxic cyanobacteria of limnic origin can reach the coastal zone.

Raphidiopsis raciborskii（原称Cylindrospermopsis raciborskii）是一种淡水蓝藻，可能产生毒素（STX）和cylindrospermopsin。其生态生理学的多功能性使其可以在从热带到温带以及从相对原始到污染的最多样化的环境中形成花朵。在巴西亚热带南部的Peri湖中，生产STX的R. raciborskii的人口不断增长自1994年以来就已经检测到这种细菌，这给使用其大约10万居民的水域带来了风险。尽管在Peri湖水域中存在蓝细菌的存在和毒性监测系统，但尚未对沿海地区（湖水流出的下游）进行评估，因此有可能向该区域的自然和养殖贝类种群提供有毒生物质。盐水生态系统。为了解决这个问题，本研究通过对Peri湖和相邻沿海地区之间的流出水进行了剖析，评估了环境变量和STX浓度。为了确定盐度对STX产量的影响并验证Perna Perna是否对三株R. raciborskii菌株进行了实验室实验。喂食了R. raciborskii培养物的贻贝会吸收并积累STX。结果表明，STX的环境浓度达到很高的水平（高达6.31 µg L ^-1 STX当量），尤其是在温暖的月份，到达沿海地区。在实验室测试中，发现该菌株可耐受4至6之间的盐度，并且盐度会影响STX的产生。此外，即使在典型的海洋盐度下（22至30），饲喂罗氏疏螺旋体的贻贝也能有效吸收和积累STX，这表明尽管盐度震荡，罗氏疏螺旋体的生物量仍然有效且有毒。这些结果提请人们注意与R. raciborskii相关的生态和健康风险 在湖泊环境和邻近海洋环境中出现水华暴涨，呼吁人们注意需要改善目标地区以及其他可能接触到利姆蓝藻的有毒蓝细菌的地方的水和贝类毒性的监测和管理系统沿海地区。