The knowledge on the composition and spatial distribution of marine benthic diatoms around the coast of South Africa remains limited. Epilithic diatom assemblages from natural intertidal rocky substrate and physico-chemical variables were investigated during July–August in 2016 and 2017 along the South African coastline. A total of 85 diatom taxa from 31 genera were observed at 15 sites along the coast. Taxa with the highest contribution included Nitzschia (9 species), Cocconeis (7 species) and Achnanthes (6 species) and the observed Shannon–Wiener diversity (H’) during the study varied from 0.44 (Kraalbaai) to 2.09 (Bird Island). Non-metric multidimensional scaling ordination (nMDS) separated the diatom assemblages into three groups with 20% similarity among sites (grouped according to coastal sections) and PERMANOVA analysis revealed a significant difference between the coastal sections. The observed diatom composition was shown to be influenced by both nutrient concentrations along the west coast and temperature along the east coast. This study provides insights on the abundance and distribution patterns of marine littoral diatoms along the coastline and the potential environmental drivers. The observed variations in diatom composition and distribution warrant further investigations if they are to be considered as potential indicator species of change.

关于南非沿海海洋底栖硅藻的组成和空间分布的知识仍然有限。在2016年和2017年的7月至8月之间，研究了沿南非海岸线的天然潮间带岩石基质的上石硅藻组合和理化变量。在沿海的15个地点共观察到31个属的85个硅藻类群。分类单元具有最高贡献包括菱形藻（9种），Cocconeis（7种）和Achnanthes（6种）和研究期间观察到的Shannon-Wiener多样性（H'）从0.44（Kraalbaai）到2.09（Bird Island）不等。非度量多维标度排序（nMDS）将硅藻组件分成三组，各站点之间有20％的相似度（按沿海地区分组），PERMANOVA分析显示沿海地区之间存在显着差异。观察到的硅藻组成受西海岸养分浓度和东海岸温度的影响。这项研究提供了关于沿海岸线的海洋沿海硅藻的丰度和分布模式以及潜在环境驱动因素的见解。