Turner has made major contributions to the understanding of many dynamical processes in the atmosphere and ocean, using imaginative laboratory model experiments and related theory. His pioneering work on turbulent convection, on entrainment in stably stratified flows, and on mixing across density interfaces is widely known and applied in various disciplines. Much international observational and interpretative study of oceanic microstructure has been initiated and inspired by Turner's work in the new field of double­ diffusive convection. Another major research contribution is his monograph 'Buoyancy effects in fluids' which covers the frontiers of knowledge and provides the first authoritative overview of the whole subject.