Water is essential to all life on earth. This unit provides foundational knowledge for students wishing to move into aquatic resource management, research and consultancy fields. It provides an introduction to aquatic biota, ecosystems and the processes that support these ecosystems. Freshwater environments are the focus of this unit but contrasts and parallels with estuarine and marine systems will be made. Contemporary understanding of Australian freshwater systems will be explored, including the plants, animals and microbes and fungi that comprise aquatic food webs. The main biological, physical and chemical processes and models that characterise standing and running waters will also be considered. Theoretical understanding will be linked with practical field experiences that focus on the wetlands and rivers of Australia.