The movement of fluids and the substances they carry play a vital role in sustaining and fostering the development of aquatic ecosystems within various water bodies, including rivers, lakes, reservoirs, and estuaries. These substances include suspended and bedload sediments shaping the physical environment, nutrients and contaminants modulating the chemical composition, micro-organisms, and species signifying biological components. This session aims to explore how these various components are transported, each characterized by unique features, across a wide range of spatial and temporal scales, to uncover underlying insights and mechanisms for understanding aquatic ecosystems on Earth's surfaces. This comprehensive session encompasses studies on fluid flow, sediments, nutrients, contaminants, microplastics, microorganisms, species eggs or larvae, eDNA, and/or their interactions. We welcome investigations utilizing theoretical, numerical, and experimental approaches to examine the transport and interactions of these biotic and abiotic components across scales within aquatic ecosystems on Earth's surface.