If you ever fly over San Francisco Bay, be sure to peer out of the window to catch a glimpse of one of the world’s most incredibly coloured landscapes - the salt evaporation ponds operated by Cargill, Inc.
Salt evaporation ponds are shallow artificial ponds designed to produce salts from sea water or other brines. The seawater or brine is fed into large ponds and water is drawn out through natural evaporation which allows the salt to be subsequently harvested. During the five years it takes for the bay water to mature into salt brine, it is moved from one evaporation pond to another. In the final stages, when the brine is fully saturated, it is pumped to the crystalizer where a bed of salt 5 to 8 inches thick is ready for harvest.
Salt ponds range from blue green to deep magenta – colored naturally by the microorganisms that thrive as salinity levels increase. The color indicates the salinity of the ponds and the type of microorganisms that’s breeding on it. Three microorganisms in particular, Synechococcus, Halobacteria, and Dunaliella, influence the color of salt ponds.
A stunning rainbow of salt-loving microbes! Bacteria have been around long enough that no matter what the conditions - deep underground, acidic lakes, caustic undersea thermal vents - there’s at least one adapted to live there. These ponds are an example.