Differential ecological adaptation of diverse Chaetoceros species revealed by metabarcoding analysis

Chaetoceros is a species-rich genus of marine planktonic diatoms that play an important role in marine ecosystems both as primary producers and as species causing harmful algal blooms (HABs). In this study, we analyzed the composition and dynamic changes in Chaetoceros species in Jiaozhou Bay, China, using metabarcoding analysis of time-series samples for the first time. Through analyzing samples collected monthly from 12 sampling sites, 25 species of Chaetoceros were detected, including nine species that were not previously reported in this ocean region, highlighting the strength of metabarcoding analysis of Chaetoceros species. Many Chaetoceros species showed strong seasonal preferences, with some species dominating in winter and spring, while others showing prominence in summer and autumn, suggesting sophisticated differential ecological adaptation. With the construction of more comprehensive datasets of reference barcodes, metabarcoding analysis could be used as the next-generation method in ecological research on Chaetoceros species and phytoplankton species of other genera.