Species Composition and New Records of Epiphytic Diatoms on Seagrass Zostera marina from Qingdao Bay, China

Epiphytes significantly contribute to the overall primary productivity of seagrass beds. Among them, diatoms are the most diverse and important component of the epiphytic community in seagrass beds. However, studies on this group of diatoms are still limited in China. In this research, we investigated the epiphytic diatoms on Zostera marina Linnaeus from Qingdao Bay on the western coast of the Yellow Sea. A total of 112 taxa belonging to 31 families and 57 genera were morphologically identified, of which 16 taxa were newly recorded in China. Each taxon was illustrated with corresponding light micrographs. The most common genera were Navicula Bory with 12 taxa, Amphora (Ehrenberg) Kützing with 10 taxa, and Nitzschia Hassall with 10 taxa. Notably, species of Cocconeis Ehrenberg were ubiquitous and found in every sample. Based on our observations, the sediment is proposed as a likely source of these epiphytic communities. None of the newly recorded diatoms had been previously reported as epiphytes on seagrasses. Our results improve the understanding of species diversity and distribution of seagrass epiphytic diatoms along the coasts of China.