Feeding selectivity of three fouling organisms and their relationship with phytoplankton community composition

Marine biofouling poses a significant influence on marine engineering equipment, and phytoplankton is the primary food source for fouling organisms, therefore, we investigated the feeding selectivity of three fouling organisms and their relationship with phytoplankton community composition using the 18S rDNA high-throughput sequencing technology. The results show that Bacillariophyta, Chlorophyta phyla, and Chaetoceros genus are dominant both in the guts of fouling organism and seawater. SourceTracker analysis reveal that fouling organisms' gut phytoplankton are largely derived from seawater and network analysis show predominantly positive co-occurrence pattern particularly within the guts of fouling organisms. Selectivity indices indicate all the fouling organisms preferential feeding on Chlorophyta and chaetoceros. Spearman correlation analysis reveal that dissolved oxygen (DO), salinity, and temperature are significantly correlated with most dominant phytoplankton genera in the gut of fouling organisms and seawater. The research, therefore, will highlight the fouling organisms have a selective regulatory effect on phytoplankton, and the phytoplankton communities that promote the growth of fouling organisms are the dominant species in the gut.