Aquatic life and ecosystems represent some of the most dynamic and biologically diverse components of the biosphere. It is vital in global biogeochemical cycles, food security, climate regulation, and ecosystem services. This review provides a comprehensive synthesis of current knowledge and emerging research areas in studying aquatic life and ecosystems for freshwater and marine environments. This paper uses a chronological approach to explore the research development in the past, present, and future. We traced the research advances in structural and functional diversity of aquatic organisms, from microbial communities to higher trophic levels, and examined the intricate ecological interactions underpinning ecosystem stability and productivity. We grasped key topics to reflect research progress and advancement in habitat degradation, pollution, climate change, and biological invasions, particularly aquatic biodiversity and ecological integrity. In the new century, scientists have applied genomic tools for ecological management and microbiome research to enhance our understanding of aquatic systems at the molecular level and explore underlying mechanisms. Applied research has emphasized conservation and management, including ecosystem-based management, aquaculture, and fisheries. By critically analyzing past developments and current knowledge gaps, this review paper provides readers with future research priorities and sustainable management of aquatic life and ecosystems in an era of rapid environmental change.



