In natural and practical applications, bubbly flows involving heat and mass transfer and chemical reactions play a critical role; yet we lack a quantitative understanding of fluxes and mixing in these turbulent flows, which is necessary to correctly predict them and produce advances in engineering technologies. A primary goal of this INCITE project is therefore to study and quantify the transport mechanisms of turbulence kinetic energy and of a diffusive scalar field in gravity-driven turbulent bubbly suspensions by using fully resolved direct numerical simulations (DNS). This implies resolving all relevant scales, including the bubble diameter, and the Kolmogorov and Bachelor scales, which correspond to the smallest vortices in the flow and the smallest scalar filaments in the flow. This research is intended to enable high performance computing (HPC) interface-resolved DNS of bubbly turbulent flows with passive scalars and realistically low values of diffusivities. Despite the multitude of applications bubbly flows have, we do not have a quantitative understanding of fluxes and mixing in turbulent flows, which is vital for correct predictions and engineering advances. Using DNS, this project studies and quantifies turbulence kinetic energy, diffusive scalar fields, and gravity-driven turbulent bubbly suspensions.