Cladophora spp. (Chlorophyta) modulate environment and create a habitat for microalgae in hypersaline waters

Cladophora spp. constantly or periodically form floating and benthic mats in Crimean hypersaline lakes and lagoons. In 2017–2018, characteristics of the Cladophora mats and the microalgae on Cladophora filaments were studied employing field research and microscopy. The whole Cladophora mat has a vertical structure, including the upper and lower layers of the floating mat and benthic mat. In total, 50 species of microalgae were found: 40 of them belonged to Bacillariophyta (Bacillariophyceae and Mediophyceae), two to Haptophyta (Coccolithophyceae), four to Miozoa (Dinophyceae), one to Chlorophyta (Zygnematophyceae) and three to Cyanobacteria (Cyanophyceae). Floating layers of the mat differed significantly in species composition from the benthic mat. The total abundance of microalgae and their biomass on Cladophora (per unit area of filaments) varied widely within sampling sites from 3.79 × 106 to 5.04 × 108 cells m–2 and 2.6 to 2197.8 mg m–2. The total mass of microalgae achieved more than 32% of the mass of Cladophora, averaging 7.7% (standard deviation = 13.3).刚毛藻属（Cladophora spp.）会持续或周期性地在克里米亚高盐湖与潟湖中形成漂浮垫与底栖垫。2017至2018年，研究团队通过野外调查与显微观测技术，对刚毛藻垫及其丝状体上附生微藻的相关特征展开了研究。完整的刚毛藻垫具有垂直分层结构，涵盖漂浮垫的上层、下层以及底栖垫。本研究共发现微藻50种：其中40种隶属于硅藻门（Bacillariophyta，包含硅藻纲Bacillariophyceae与中硅藻纲Mediophyceae），2种隶属于定鞭藻门（Haptophyta，颗石藻纲Coccolithophyceae），4种隶属于双鞭毛虫门（Miozoa，涡鞭毛藻纲Dinophyceae），1种隶属于绿藻门（Chlorophyta，接合藻纲Zygnematophyceae），3种隶属于蓝细菌门（Cyanobacteria，蓝藻纲Cyanophyceae）。漂浮垫层与底栖垫层的物种组成存在显著差异。附生于刚毛藻丝状体单位面积上的微藻总丰度与生物量在各采样点间差异显著，范围分别为3.79×10^6 至5.04×10^8 个·m^-2，以及2.6 至2197.8 mg·m^-2。微藻总生物量最高可达刚毛藻生物量的32%以上，平均占比为7.7%（标准差为13.3）。