1586 / 2024-10-07 06:34:26

Testing the biogeographic boundary in Taiwan waters with eDNA approach

Environmental DNA (eDNA),metabarcoding,Sea surface current pattern,Community assemblage

Session 58 - Molecular approaches integrated with AI to Oceanography: from DNA to global-scale processes

The spatial and temporal variations of marine communities are crucial for understanding the dynamics of marine ecosystems. Environmental DNA (eDNA) metabarcoding offers insights into biodiversity and species composition of the habitats without direct observations. Here, we applied eDNA approach as a tool to test the biogeographic boundary found previously as well as the effect of water sampling depth. The water samples were collected from 12 sites covering the north, west, south, and east of Taiwan, including islands such as Penghu, Liuqiu, and Dongsha during summer and winter. Both surface and bottom water samples were collected. A total of 240 samples were used, targeting 18S and ITS2 gene regions to test whether the community structure based on these assays fit with our hypothesis. Signals from diverse taxonomic groups were detected, representing 251 unique species from ITS2 and 830 from the 18S assay. Furthermore, two assays combinedly revealed 21 unique marine metazoan phyla, including Cnidaria (mostly hard corals), Arthropoda, Mollusca, Annelida, and Porifera as the dominant taxa. Overall community composition varied significantly between seasons. Sites located in northern and southern regions of Taiwan showed a significant difference in community composition for both assays (P < 0.0001). Moreover, a significantly different community structure was found between water samples collected from surface and bottom water. Our eDNA-based communities showed evidence of distinct multi-taxon assemblages over the known sub-tropical and tropical boundary of marine organisms. In terms of hard coral ZOTU richness, an increasing trend was revealed towards the southern Taiwan sites. We suggest that these observation patterns are potentially influenced by environmental factors such as sea surface temperatures, habitat topography as well as local anthropogenic disturbances over the Taiwan Strait. By leveraging eDNA analysis, our study revealed that this sub-tropical and tropical boundary might be a general pattern for most of the marine organisms inhabiting the waters of Taiwan.