Brine channels are formed in sea ice under certain constraints and represent a habitat of different microorganisms. The complex system depends on a number of various quantities as salinity, density, pH value or temperature. Each quantity influences the process of brine-channel formation. We develop a suitable phenomenological model for the formation of brine channels both referring to the Ginzburg-Landau theory of phase transitions as well as to the chemical basis of morphogenesis according to Turing. We construct a Turing space in which a structure formation is possible and conclude from the critical wave number on the size of the structure and the critical parameters. The theoretically deduced transition rates have the same magnitude as the experimental values. The model creates channels of similar size as observed experimentally. An extension of the model towards channels with different sizes is possible. Microscopic insights into the brine-channel formation in sea ice can be achieved by ‘ab initio’ calculations with the help of molecular dynamics simulations. If we place halide ions in water we hope to find the onset of a brine-channel formation and to determine the minimal size of brine pockets.