Salt Road

Funny how natural resources rise and fall in our estimation.

There was a time when salt – plain old salt, the stuff we buy for pennies – was the cornerstone of empires, the arrow of conflict, the reason for Roman roads and the thorn that pricked societies to revolution.

Precious salt preserved food for long journeys, drew out illness, was strewn on farmlands to ruin economies, and only lastly lent spice to life.

Industrial progress changed all that, and now salt is so common and cheap that even the exotic varieties (black volcanic, spiced, Himalayan) are affordable.

Salar de Uyuni, southwest Bolivia

World’s largest salt flats at Salar de Uyuni, southwest Bolivia

The salt flats in southwest Bolivia are comprised of sodium chloride and traces of other elements. Notably, large amounts of lithium, which has recently become interesting as a key element for the batteries upon which modern life is built, i.e. those for consumer electronic devices.

Lithium makes up only 0.0007% of the earth’s crust, and is usually extracted through the electrolysis of lithium chloride (LiCl). Lithium is not found free in nature.

It’s the lightest metal element and can be alloyed with all manner of other metals and substances to make strong, light materials. Special light glass for telescope lenses, for example, or metal for aircraft.

According to TIME magazine, “For decades the salt flats have simply been a curiosity for adventure travelers (…), and a source of subsistence for impoverished salt gatherers who scrape mounds of salt and sell it as table salt. The production of lithum, which requires months of slow evaporation and weeks of refining in a lab, could transform the salt flats into the economic engine of Bolivia.”

I had started this post wanting to write about the decreasing value of salt as it became more common, and the possible increasing value of water as it becomes more scarce, but got completely sidetracked by this lithium story in Bolivia.
Sometimes curiosity takes us on the most unexpected side routes.
A good overview of salt history here.

Red Farms

Hutt Lagoon, Australia Photo: Steve Back Art

Hutt Lagoon, Australia
Photo: Steve Back Art

Back in the deeply-tanned 1970s, I knew someone who decided that he would augment his early spring paleness to get ahead of the season. Spray-on fake tans didn’t yet exist, and the bottled stuff was not only streaky, but considered to ‘unnatural’ for those groovy lentil-and-granola days. So what did he do? He ingested beta-carotine in the form of carrots. Not just some carrots; epic amounts of carrots. Within a couple of weeks, his skin color had indeed changed – from his normal olive-skinned pale to a sort of apricot-hued orange. There’s even a term for this effect. Carotenodermia. He stopped eating carrots right away.
Beta-carotine is an organic compound widely popular in nutritional supplements, food coloring, medical treatments and cosmetics. It can be found in red or orange-colored plants, some dark green plants (such as kale, but the deep chlorophll green masks the orange tinge of beta-carotine), and in the liltingly named Dunaliella salina, a kind of green algae that has its home in salt evaporation ponds.
So why is the green algae distinctly ungreen? For the same reasons that we value it – the red hue comes from D. salina‘s ability to survive intense sun and salt by using high levels of beta-carotene and glycerol as cellular antioxidants.
The photos above and here are of the largest beta-carotene farm in the world, the red salt ponds of Hutt Lagoon in Australia.

World's largest red algae (D. salina) ponds - a source of natural beta carotene  Photo: Steve Back Art Hutt Lagoon, Western Australia Photo: Steve Back via PetaPixel

World’s largest D. salina ponds – a source of natural beta carotene
Hutt Lagoon, Western Australia
Photo: Steve Back Art

This photo is from a salt evaporation pond in the San Francisco South Bay – as the salt evaporates and the water becomes ever more uninhabitable for most organisms, D. salina thrives and the red color deepens – until all the water is gone and the remaining salt itself is harvested.

Photo: Doc Searles via Wikipedia

Photo: Doc Searles via Wikipedia