Microchannel formation in seaice as habitat for microalgae

The formation of saline brine channels in seaice is described by two coupled order parameters, the tetrahedricity as structure of ice and the salinity. Their evolution equations follow from a Ginzburg-Landau-functional in the form of a phase-field theory conserving salinity. The stability analysis provides the phase diagram in terms of two parameters, one describing the velocity of the freezing process and the other one characterizing the velocity of structure formation. In thermodynamics these parameters determine the supercooling or superheating region and the specific heat respectively. In contrast to the Turing model the diffusivity does not enter this phase diagram but determines only the structure size. The numerical solution shows a microstructure formation of brine inclusions in agreement with the measured samples dependent on the salinity and temperature.