Diversity of marine algae assessed by environmental DNA metabarcoding: A case study from Gili Genting, Gili Labak, and Karang Takat-Indonesia

Environmental DNA (eDNA) metabarcoding has emerged as a powerful tool for detecting and monitoring marine biodiversity, particularly for taxa that are difficult to identify using traditional methods. The objective in this study is to assess the diversity of marine algae, including Chlorophyta, Phaeophyta, and Rhodophyta, in three coastal sites of Indonesia: Gili Genting, Gili Labak, and Karang Takat. eDNA samples were collected and sequenced to identify algal taxa and estimate their relative abundance across locations. The results revealed clear spatial variations in algal communities. Gili Genting showed dominance of Micromonas pusilla and other Chlorophyta species associated with nutrient-enriched waters. Karang Takat exhibited higher Rhodophyta diversity, reflecting a stable and mature benthic environment. Gili Labak displayed lower algal diversity and abundance, possibly due to limited substrate availability or lower DNA yield. These findings highlight the effectiveness of eDNA metabarcoding in detecting fine-scale spatial patterns of algal diversity and provide valuable insights for monitoring and managing tropical coastal ecosystems in Indonesia.