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.

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.