Harmful events associated with epibenthic dinoflagellates, have been reported more frequently over the last decades. Occurrence of potentially toxic benthic dinoflagellates, on the leaves of two magnoliophytes (Cymodocea nodosa and Zostera noltei) and thalli of the macroalgae (Ulva rigida), was monitored over one year (From May 2015 to April 2016) in the Bizerte Bay and Lagoon (North of Tunisia, Southern Mediterranean Sea). The investigated lagoon is known to be highly anthropized. This is the first report on the seasonal distribution of epibenthic dinoflagellates hosted by natural substrates, from two contrasted, adjacent coastal Mediterranean ecosystems. The environmental factors promoting the development of the harmful epibenthic dinoflagellates Ostreopsis spp., Prorocentrum lima and Coolia monotis were investigated. The highest cell densities were reached by Ostreopsis spp. (1.9 × 10³ cells g⁻¹ FW, in October 2015), P. lima (1.6 × 10³ cells g⁻¹ FW, in June 2015) and C. monotis (1.1 × 10³ cells g⁻¹ FW, in May 2015). C. nodosa and Z. noltei were the most favorable host macrophytes for C. monotis (in station L2) and Ostreopsis spp. (in station L3), respectively. Positive correlations were recorded between Ostreopsis spp. and temperature. Densities of the epibenthic dinoflagellates varied according to the collection site, and a great disparity was observed between the Bay and the Lagoon. Maximum concentrations were recorded on C. nodosa leaves from the Bizerte Bay, while low epiphytic cell abundances were associated with macrophytes sampled from the Bizerte Lagoon. The observed differences in dinoflagellate abundances between the two ecosystems (Bay-Lagoon) seemed not related to the nutrients, but rather to the poor environmental conditions in the lagoon.

在过去的几十年中，与上鞭毛鞭毛藻相关的有害事件的报道更为频繁。在比塞大湾和泻湖（2015年5月至2016年4月）的一年（2015年5月至2016年4月）中，对两个大型生植物（Cymodocea nodosa和Zostera noltei）和大型藻类（Ulva僵硬）的叶片上的潜在毒性底栖鞭毛鞭毛藻进行了监测突尼斯北部，地中海南部）。被调查的泻湖是高度人工的。这是关于来自两个相对的，相邻的沿海地中海生态系统的天然底物所携带的表皮甲藻基藻酸酯的季节性分布的第一份报告。促进有害表皮鞭毛藻发育的环境因素研究了骨质疏松症，利马原球菌和单眼小Cool虫。Ostreopsis spp达到了最高的细胞密度。（1.9×10 ^3个细胞g ^-1 FW，2015年10月），利马假单胞菌（1.6×10 ^3个细胞g ^-1 FW，2015年6月）和C. monotis（1.1×10 ^3个细胞g ^-1 FW，2015年6月）2015年5月）。C. nodosa和Z. noltei是C. monotis（在站L2）和Ostreopsis的最有利寄主植物spp。（分别在站点L3中）。Ostreopsis spp之间记录正相关。和温度。表皮鞭毛鞭毛虫的密度根据收集地点而变化，并且在海湾和泻湖之间观察到很大的差异。从比塞大湾的结节梭菌叶子上记录到最大浓度，而从比塞大泻湖采样的大型植物与低的附生细胞丰度有关。在两个生态系统（Bay-Lagoon）之间观察到的鞭毛丰富度差异似乎与养分无关，但与泻湖中恶劣的环境条件有关。