Don’t Call it a "Salt Pond"

“This is what we call a crystallizer bed,” says Cargill’s Pat Mapelli. “This is very engineered, managed and manicured, where everything has been rolled, graded, sloped and compacted. Whereas a salt pond is essentially a diked off area that has been flooded with salt water.”

The vibrant pink hue comes from a natural source: halobacterium and microscopic algae.

As the water gets saltier, some microbes can’t hack it and they die off. But others are specially adapted to salty conditions and they flourish, changing the color of the water.

“When they get stressed as the salinity increases, they produce that red color,” says Alizo-Martell.

The saltier the water, the redder the microbes get. That color aids in the salt-making process by absorbing sunlight and increasing evaporation. Clear water doesn’t absorb as much light.

Once several inches of salt form, Cargill begins the harvest, which lasts from September to December.

“It’s just beautiful,” says Alizo-Martell, picking up a handful of the flaky, white cubes. “It’s so weather dependent. You had a bad year, you get not much salt.” A lot of rain slows down the process.

In all, it takes three years and a thousand gallons of bay water to produce just one pound of salt. From here, it goes to a refinery where it’s cleaned, sized and sold as sea salt, bearing the Morton’s or Diamond Crystal brand.

But only 3 percent of the salt ends up on our table. The rest supplies a huge range of industrial processes, from pharmaceuticals to food production, water treatment and road salt.

Gold Rush History

Believe it or not, the Bay Area may not be what it is today without its salt. Harvesting salt from the Bay dates back to Native American groups like the Ohlone, but demand really picked up in the 1850s.

“As people migrated from the east to the west, mostly around the discovery of gold, there was a need for salt,” says Mapelli. “Everybody traveled with salt.”

Without refrigeration, salt was how people preserved food.

“It was almost worth its weight in gold,” he says.

Salt-making boomed through the 1970s, when Cargill bought the operation. 44,000 acres of the bay were in production then, but today, it’s just 8,000.

That’s because the market for salt shifted and so did our view of what San Francisco Bay should be. The salt ponds used to be marshes, which, around the time of the Gold Rush, were seen as wasteland.

“There was an encouragement by both the state and federal government to put what they considered wasteland or swamp and overflow lands into economic use,” Mapelli says.

Today, the Bay has lost more than 80 percent of its marshes. So, in 2003, the federal and state governments bought thousands of acres of ponds from Cargill. In the biggest ecosystem restoration project on the West Coast, the ponds are being reconnected to the Bay and restored to their original status as marshlands to support wildlife and act as buffers against rising sea levels.

For Bay Curious questioner Ann Vercoutere, the ponds are one of the few things that haven’t changed from her childhood in the South Bay.

When she was a kid in Mountain View, “there were lots of orchards around,” she says. “Some of our summer jobs were going to work picking Italian prune plums with the migrant workers. Shoreline Amphitheater was the city dump. That was always a fun Saturday to go with our dad and pick through the dump and look for stuff.”

Now, the salt ponds border some of the most expensive real estate in the nation, not far from gleaming tech campuses. The chances of starting a large, industrial salt-making operation in the Bay today are effectively zilch, for financial and environmental reasons.