The equation for the conservation of total mechanical energy (kinetic, gravitational, and elastic energy) is derived from the conservation of momentum and mass averaged over the volume of oceans to equate the production and dissipation of mechanical energy in a statistically steady ocean. The work done by the atmosphere dominates production and is estimated as 0.1 W/m2 from synoptic data which is consistent with most (but not all) of the reported observations of turbulent dissipation. Potential energy production contributes only 0.2% to the total production implying an eddy diffusivity of buoyancy of 10-5 m2/s and a thermal Cox number of 200. The ''low'' values of diffusivity derived from microstructure observations appear to reflect a relatively small potential energy production.