Comparison of Environmental DNA Metabarcoding and Underwater Visual Census for Assessing Macrobenthic Diversity

Area of Science:

• Marine biology
• Molecular ecology
• Environmental science

Background:

• Environmental DNA (eDNA) is revolutionizing ecological research, especially in aquatic environments.
• Optimal sampling matrices (water vs. sediment) and the role of eDNA versus traditional underwater visual census (UVC) require further clarification.

Purpose of the Study:

• To systematically compare the diversity of benthic macrofauna using water eDNA, sediment eDNA, and UVC.
• To evaluate the complementarity of these methods for biodiversity assessment in subtidal zones.

Main Methods:

• Integration of three distinct sampling approaches: water eDNA, sediment eDNA, and underwater visual census (UVC).
• Systematic comparison of benthic macrofauna diversity in the subtidal zones of the Nanji Islands, China.

Main Results:

• Sediment eDNA yielded the highest species richness, while UVC showed the lowest.
• Each method detected unique species profiles, with limited overlap at the order level and below.
• eDNA excelled at detecting Annelida and Arthropoda, whereas UVC was vital for identifying taxa like Bryozoa.

Conclusions:

• The distinct species detected by each method highlight their complementary roles in biodiversity assessment.
• Integrating water eDNA, sediment eDNA, and UVC is necessary for a comprehensive understanding of benthic macrofauna.
• Further refinement of eDNA techniques, including primer development, is recommended for enhanced biodiversity monitoring.