Host/Organiser: The Bremen Society for Natural Sciences
Name of the event: International Conference for YOUNG Marine Researchers – ICYMARE
Place: Bremerhaven, Germany
Date: 8th to the 12th of September 2025
Partners involved: CONISMA
Natural Sampler DNA (nsDNA) refers to environmental DNA (eDNA) retained by filter-feeding organisms such as mussels or sponges. Recent studies have highlighted the potential of nsDNA metabarcoding as a cost-efficient tool for biodiversity monitoring, with sponges emerging as the most studied natural samplers. However, most research has focused on fish, while invertebrate communities remain limited—primarily due to the overabundance of host DNA in samples. In this study, communities associated with the sponge Aplysina aerophoba were assessed using an integrative approach that combined nsDNA metabarcoding and morphological analysis. Metazoan diversity was characterized by amplifying the universal COI barcode region. To reduce host DNA amplification, blocking primers specific to A. aerophoba were designed. The addition of an annealing-inhibiting blocking primer at a 1:10 ratio to the amplifying primer significantly improved sequencing depth for non-host organisms, increasing OTU counts per sample by an average of 130%. Morphological analysis of the same samples revealed site-level patterns not detected by molecular methods, underscoring its complementary value. These findings demonstrate that blocking primers offer a straightforward solution to reduce host DNA amplification in nsDNA metabarcoding. Further validation is needed using other natural samplers to evaluate potential inhibitory effects on non-host DNA.
Contribution: Testing different blocking primers for nsDNA metabarcoding in sponge Aplysina aerophoba to characterise sponge-associated fauna via metabarconding and fostering monitoring of restoration activities.
Link: www.icymare.com