Thoughts on the “missing link” between saltworks biology and solat salt quality

Although solar salterns worldwide use seawater of identical chemical composition as the raw
material for salt production, the size and quality of the halite crystals that precipitate in the
crystallizer ponds is highly variable. Biological processes have been implicated to be responsible for
the differences observed, but the “missing link” between saltworks biology and solar salt quality has
never unequivocally been identified. This paper presents an overview of the different organic
chemicals that are formed by the members of the microbial communities in saltern evaporation and
crystallizer ponds as osmotic stabilizers as well as different compounds formed during further
microbial metabolism of those osmotic solutes. Examination of the in situ concentrations and the
possible role of glycerol, glycine betaine, ectoine, dihydroxyacetone, acetate, lactate, and other
organic compounds failed to identify one or more compounds that may accumulate at concentrations
high enough to significantly modify the formation of sodium chloride crystals in the salterns and to
negatively influence the quality of the salt produced.