Metabarcoding hyperdiverse kelp holdfast communities on temperate reefs: an experimental approach to inform future studies.

Dr Vanessa Arranz¹, Dr Libby Liggins, Dr David Aguirre

¹Massey University, Auckland,

Abstract:

Classical taxonomic approaches to quantifying biodiversity can be notoriously laborious and restrictive. Instead, molecular metabarcoding is emerging as a rapid, high-throughput and cost-effective tool to catalogue biodiversity. Despite the appeal of metabarcoding, methodological and procedural biases must be understood before robust biodiversity inferences can be made. Here, we use CO1 metabarcoding to characterize marine eukaryote communities associated with Ecklonia radiata, the dominant eco-engineering kelp of temperate Australasia. To establish a standardized and reproducible community metabarcoding protocol, we examined the influence of different sample preparation, laboratory and bioinformatic steps on inferences of species richness and composition of communities associated with E. radiata holdfasts sampled from northeastern New Zealand. Specifically, we examined: the effect of sieving the community into different size fractions, the replicability of results across DNA extractions, PCR, and sequencing. Overall, we found that sieving the community into two size fractions before DNA extraction enabled detection of a greater diversity of taxa than not sieving samples. When compared with traditional morphology-based inventories of kelp holdfast biodiversity, we found that although the taxonomic precision of our metabarcoding approach at the species and genus level was limited by the availability of reference sequences in public repositories, we recovered approximately 40% more taxa and a greater taxonomic breadth of organisms than morphological surveys (e.g. 18 phyla as compared with 14 phyla). Based on our findings, we provide methodological guidelines for the use of metabarcoding as a tool for surveying and monitoring the hyperdiverse species assemblages associated with kelp holdfasts.

Biography:

Originally from Barcelona, moved to New Zealand for my PhD and somehow still here. I am a lecturer based at Massey University Auckland. Interested in applying genetic/genomic tools for understanding the dynamics of marine systems and conserving its precious life. Recently immerse in the amazing and fast-growing genomics field, using Next Generation Sequencing (NGS) technologies and bioinformatics in various projects including environmental DNA metabarcoding and whole-genome sequencing (WGS) applied to kelp forests and coral reef ecosystems.