There are a couple of places in the world famous for their brine ponds. San Francisco Bay is one of them. Here, many salt ponds date back to the 1800s. In 1854, salt mining was among the largest industries in California, with the San Francisco Bay area leading the way. Over 80 percent of wetlands at that time were devoted to salt production. Nowadays, San Francisco is still a major salt producer—and in fact the salt ponds are something of an attraction. When flying into or out of the San Francisco International Airport, it is possible to catch an aerial glimpse of the ponds. The colors are beautiful—bright greens, pink, orange and red, very vibrant and saturated. These colors can be seen from space, and they’re caused by a variety of things. Green comes from algae growing in low salinity ponds, while orange comes from tiny brine shrimp growing on the ponds. Pink and red ponds are the ones that are highest in saline, and the color comes from halobacteria growing within them.
Another famous salt pond development is located in Maras, Peru. These ponds, which run down a slope, are quite old. In fact, salt has been harvested in the area since pre-Inca times. Today, the salt ponds are used to capture water from a highly salty spring that lets out at a natural outlet above the ponds. The flowing water goes into a system of channels that directs it into salt ponds running down the slope through several hundred ancient terraced ponds. These are all very small ponds, most less than four meters square. These ponds also evaporate very quickly—in just a few days. Interestingly, salt harvesters are able to grade the salt as they harvest. Upper layers are typically white or pink, and these are sold as table salt. Lower layers will be a brownish color, which is lesser quality, and are sold as bulk salt. The bottom layer is brown, and is used for industrial purposes.
