This study investigated the genetic diversity of phytoplankton communities in six shallow lagoons located on the French coast of the northwestern Mediterranean Sea that represented a trophic gradient ranging from oligotrophic to hypereutrophic. The phytoplankton communities were sampled once a month from spring (May) to the beginning of autumn (September/early October) in 2012 and fractionated by size. Metabarcodes were generated from cDNAs by targeting the D1-D2 region of the 28S rRNA gene and pyrosequenced using Roche 454 technology. Examination of the annotated barcodes revealed harmful algal species not previously documented in these lagoons. Three ichthyotoxic species belonging to Pfiesteriaceae were detected: Luciella masanensis was relatively widespread and abundant in many samples, whereas Pfiesteria piscicida and Stoeckeria changwonensis were found as single barcode sequences. Furthermore, a phylogenetic analysis of barcodes annotated as belonging to Pfiesteriaceae suggested the existence of two previously undescribed clades. The other toxic or potentially harmful dinoflagellates detected through rare barcodes were Dinophysis acuminata, Vulcanodinium rugosum, Alexandrium andersonii and A. ostenfeldii. The two most abundant dinoflagellate taxa were Gymnodinium litoralis and Akashiwo sanguinea with respect to sequence numbers. Four diatom species from the genus Pseudo-nitzschia that potentially produce domoic acid were identified (P. galaxiae, P. delicatissima, P. brasiliana and P. calliantha). These observations are discussed in terms of the literature and monitoring records related to the identified taxa in this Mediterranean area.

这项研究调查了位于西北地中海法国海岸的六个浅泻湖中浮游植物群落的遗传多样性，这些泻湖代表了从贫营养到富营养化的营养梯度。从2012年春季（5月）到秋季初（9月/ 10月上旬），每月对浮游植物群落进行一次采样，并按大小进行了划分。通过靶向28S rRNA基因的D1-D2区，从cDNA中生成元条形码，并使用Roche 454技术进行焦磷酸测序。检查带注释的条形码发现了这些泻湖中以前没有记录到的有害藻类。检出了3个属于费氏菌科的鱼鳞毒素：马氏Luciella masanensis在许多样品中相对较广泛分布，而结果发现，Pfiesteria piscicida和Stoeckeria changwonensis为单个条形码序列。此外，对被注释为肺藻科的条形码的系统发育分析表明存在两个先前未描述的进化枝。通过稀有条形码检测到的其他有毒或潜在有害的鞭毛藻有Dinophysis acuminata，Vulcanodinium rugosum，Alexandrium andersonii和A. ostenfeldii。就序列号而言，两个最丰富的鞭毛藻类群是裸子草和赤裸几内亚。从该属四个硅藻拟菱形藻潜在地产生软骨藻酸被鉴定（P. galaxiae，P.柔弱，P. Brasiliana公司和P.衔）。这些观察结果是根据与该地中海地区已识别分类单元有关的文献和监测记录进行讨论的。