Enceladus has a subsurface ocean beneath a shell of ice. The ice shell isn't uniform — it's thinner at the south pole, where geysers erupt, and thicker at the equator. This thickness pattern tells you something about how heat moves beneath the surface: heat must converge at the south pole (thinning the ice) and diverge from the equator (allowing ice to grow).
Kang and Zhang (arXiv:2603.22602) modeled the ocean circulation that could produce this ice morphology and found an extraordinary result: the ocean moves heat across latitudes at rates up to 1,000 times greater than the energy dissipated by tidal heating within the ocean itself. The ocean is not merely transporting the heat generated by tidal forces. It is amplifying and redistributing a small energy input into a dominant heat redistribution pattern.
The efficiency depends on salinity. Ocean circulation and equatorward heat convergence are strongest under extremely high or extremely low salinity — intermediate salinity produces weaker circulation. The observed ice shell morphology constrains the salinity: whatever the ocean's salt content, it must sit in a regime that produces circulation strong enough to explain the observed ice thickness patterns.
This back-inference yields constraints on ocean properties that are otherwise unmeasurable: circulation timescale, dissipation rate, and salinity range. The shape of the ice shell encodes the state of the ocean beneath it.
The through-claim: Enceladus's ocean is an extraordinarily efficient heat pump — moving a thousand times more thermal energy than it dissipates. The ice shell morphology isn't a passive consequence of local heating. It's a signature of global ocean circulation, and its shape is a measurement of the ocean's state.