Dense communities of carotenoid-rich members of the Halobacteria (Euryarchaeota), the bacterium Salinibacter (Bacteroidetes) and the eukaryotic alga Dunaliella color the brines of most saltern crystallizer ponds red. The first report we found from the western world mentioning these red brines dates from 1765: the Encyclopédie of Diderot and coworkers. Earlier descriptions of solar salterns since Roman times do not mention red ponds. These include the Astronomica of Manilius, Pliny's Naturalis Historia (1st century), the description of Italian salterns in De Reditu Suo by Namatianus (5th century), Agricola's De Re Metallica (1556) and an anonymous description of French salterns (1669). This suggests that in earlier times, saltern brines may not have been red. In salterns which are operated today in the traditional way as practiced in the Middle Ages, no red brines are observed. Prokaryotic densities in the salterns of Sečovlje (Slovenia) and Ston (Croatia) are an order of magnitude lower than in modern saltern crystallizers. This is probably due to the much shorter residence time of the brine in the traditionally operated salterns. In China, red saltern brines were documented earlier: in Li Shizhen's compendium of Materia Medica Ben Cao Kang Mu, completed in 1578 and based on older sources.
Bibliographical noteFunding Information:
Red saltern brines were not mentioned in the western literature before the 18th century, probably because the way saltern crystallizers were operated did not support massive development of halophilic microorganisms. Halobacteria Salinibacter Dunaliella carotenoids saltern history Israel Science Foundation 10.13039/501100003977 2221/15 National Natural Science Foundation of China 10.13039/501100001809 4151101015 Natural Science Foundation of Jiangsu Province 10.13039/501100004608 BK20151611
This work was supported by grants from the Israel Science Foundation (Grant No. 2221/15), the National Natural Science Foundation of China (Project No. 4151101015) and the Natural Science Foundation of Jiangsu Province (Project No. BK20151611).
© 2019 FEMS.