Sydney Harbour is one of Australia’s most beautiful icons, but most of us are unaware that the waterway is a living and breathing ecosystem. Ruth Hessey speaks with University of Sydney researcher Edwina Tanner about how the Sydney Harbour Estuary absorbs carbon and the immediate threats the system is facing.

Edwina Tanner is the coordinator of the Marine Studies Institute at the University of Sydney and the project leader of the World Harbour Project.