In this talk, we consider the dependence of the Lyapunov exponents of the fluid particles on Reynolds and Mach numbers. A general inequality on the first Lyapunov exponent is considered and the dependence on the Reynolds number is reviewed in the case of zero Mach number. We demonstrate that for compressible turbulence at a finite Mach number, the sum of Lyapunov exponents remains fixed at zero. For compressible flow, universality becomes an issue. We describe the recent progress in the study.