Cyanobacteria inhabiting lotic environments have been poorly studied and characterized in Mexico, despite their potential risks from cyanotoxin production. This article aims to fill this knowledge gap by assessing the importance of benthic cyanobacteria as potential cyanotoxin producers in central Mexican rivers through: (i) the taxonomic identification of cyanobacteria found in these rivers, (ii) the environmental characterization of their habitats, and (iii) testing for the presence of toxin producing genes in the encountered taxa. Additionally, we introduce and discuss the use of the term “CyanoHAMs” for lotic water environments. Populations of cyanobacteria were collected from ten mountain rivers and identified using molecular techniques. Subsequently, these taxa were evaluated for genes producing anatoxins and microcystins via PCR. Through RDA analyses, the collected cyanobacteria were grouped into one of three categories based on their environmental preferences for the following: (1) waters with high ionic concentrations, (2) cold-temperate waters, or (3) waters with high nutrient enrichment. Populations from six locations were identified to genus level: Ancylothrix sp., Cyanoplacoma sp., and Oxynema sp. The latter was found to contain the gene that produces anatoxins and microcystins in siliceous rivers, while Oxynema tested positive for the gene that produces microcystins in calcareous rivers. Our results suggest that eutrophic environments are not necessarily required for toxin-producing cyanobacteria. Our records of Compactonostoc, Oxynema, and Ancylothrix represent the first for Mexico. Four taxa were identified to species level: Wilmottia aff. murrayi, Nostoc tlalocii, Nostoc montejanii, and Dichothrix aff. willei, with only the first testing positive using PCR for anatoxin and microcystin-producing genes in siliceous rivers. Due to the differences between benthic growths with respect to planktonic ones, we propose the adoption of the term Cyanobacterial Harmful Algal Mats (CyanoHAMs) as a more precise descriptor for future studies.

尽管蓝藻产生蓝藻毒素具有潜在风险，但在墨西哥，对栖息在海水环境中的蓝藻的研究和特征分析却很少。本文旨在通过以下方式评估底栖蓝藻作为墨西哥中部河流潜在蓝藻毒素生产者的重要性，从而填补这一知识空白：（i）这些河流中发现的蓝藻的分类学鉴定，（ii）其栖息地的环境特征，以及（ iii) 测试遇到的类群中是否存在产生毒素的基因。此外，我们还介绍并讨论了术语“CyanoHAM”在流动水环境中的使用。从十条山区河流中收集了蓝藻种群，并使用分子技术进行了鉴定。随后，通过 PCR 评估这些类群中产生毒素和微囊藻毒素的基因。通过 RDA 分析，收集的蓝藻根据其对以下环境的偏好分为三类之一：（1）高离子浓度的水，（2）冷温带水，或（3）营养丰富的水。来自六个地点的种群被鉴定到属水平：Ancylothrix sp.、Cyanoplacoma sp. 和Oxynema sp.。后者被发现含有在硅质河流中产生赤藻毒素和微囊藻毒素的基因，而Oxynema在钙质河流中产生微囊藻毒素的基因检测呈阳性。我们的结果表明，富营养化环境不一定是产生毒素的蓝藻所必需的。我们对Compactonostoc、Oxynema和Ancylothrix的记录在墨西哥尚属首次。四个类群被鉴定到物种水平：Wilmottia aff。Murrayi、Nostoc tlalocii、Nostoc montejanii和Dichothrix aff。willei，只有第一个使用 PCR 对硅质河流中的虾毒素和微囊藻毒素产生基因进行检测呈阳性。由于底栖生长与浮游生长之间的差异，我们建议采用术语蓝藻有害藻垫（CyanoHAM）作为未来研究的更精确的描述符。