DNA metabarcoding for high-throughput monitoring of estuarine macrobenthic communities

Abstract

Morphology-based profling of benthic communities has been extensively applied to aquatic ecosystems’ health assessment. However, it remains a low-throughput, and sometimes ambiguous, procedure. Despite DNA metabarcoding has been applied to marine benthos, a comprehensive approach providing species-level identifcations for estuarine macrobenthos is still lacking. Here we report a combination of experimental and feld studies to assess the aptitude of COI metabarcoding to provide robust species-level identifcations for high-throughput monitoring of estuarine macrobenthos. To investigate the ability of metabarcoding to detect all species present in bulk DNA extracts, we contrived three phylogenetically diverse communities, and applied four diferent primer pairs to generate PCR products within the COI barcode region. Between 78–83% of the species in the contrived communities were recovered through HTS. Subsequently, we compared morphology and metabarcoding-based approaches to determine the species composition from four distinct estuarine sites. Our results indicate that species richness would be considerably underestimated if only morphological methods were used: globally 27 species identifed through morphology versus 61 detected by metabarcoding. Although further refnement is required to improve efciency and output of this approach, here we show the great aptitude of COI metabarcoding to provide high quality and auditable species identifcations in estuarine macrobenthos monitoring.