Microbial filtration by mussels Targeted loci environmental

The aim of this project was to assess the variations in the abundance and composition of the entire protistan community -before and after a biofiltration treatment in aquaculture tanks-, using a next-generation sequencing (NGS) methodology (Illumina Miseq). Expectations were that NGS would expand available information and describe the entire eukaryotic community by including ecologically important groups, such as parasites, degraders, and nanoheterotrophs, otherwise unverifiable by conventional microscopy. For this, samples were taken at six dates during a 35 day experiment from a Control and an Experimental tank (i.e before and after biofiltration by blue mussels). In total, 12 samples were sequenced and analyzed with bioinformatics tools. In this study, morphological analyses and sequencing were generally in accordance with capturing frequency shifts of phytoplankton reported in Delegrange et al. (2015). Sequencing revealed an extensive diversity in the protistan community characterized by the presence of a numerous, persisting and highly diversified community of endosymbionts/degraders/parasites. Biofiltration modified the protistan community structure and overall the number of OTUs (Operational Taxonomic Units) was lower in the Test relative to the control tanks. This decrease was observed for all trophic groups and was pronounced for potential parasites. Finally, The presence of numerous fish parasites in the samples could be a subject worth exploring in the future using sequencing methods.