Human activities are significantly reshaping biodiversity, with potential ecosystem changes. However, most studies have only looked at individual organismal groups, thus the overall estimation of cross-domain biodiversity within coastal ecosystem and the human impacts on multi-trophic levels remain poorly understood. To bridge these gaps, we sampled 108 benthic water samples across three highly heterogeneous coastal waters of Hong Kong SAR. and four seasons by combining eDNA metabarcoding of multi-taxa, diver-based visual surveys on coral and bony fish community, enumeration of unicellular organisms by flow cytometry, and measurement of environmental parameters. This comprehensive methodology enabled a detailed study of the spatiotemporal dynamics of marine metazoans (including hard coral, sponge, and bony fish), protists, and prokaryotes. Our goals are to: 1) How spatial and temporal changes influence cross-taxon patterns and what the major environmental drivers are; 2) What the multi-trophic interactions are and how could they be influenced in ecosystem scale. We are currently working on the analysis of biodiversity from sequencing data of multiple universal primers and construct multi-trophic interaction network. This study will enhance our understanding of macroecological patterns of both microscopic and macroscopic organisms and offer a comprehensive view of the multi-trophic interactions within coastal ecosystems.

coastal ecosystem, community diversity, environmental DNA, multi-trophic interaction