Painting the Town Lake Red:  A lake in the Camargue region of France, where the Rhone meets the sea, turns blood red.

Painting the Town Lake Red:  A lake in the Camargue region of France, where the Rhone meets the sea, turns blood red. Lake Retba in the western African nation of Senegal looks like strawberry milkshake. No, it’s not the apocalypse, it’s party time for the marine alga Dunaliella salinas. This single celled microscopic member of Chlorophyta thrives in extremely salty water where not much else survives. Because it has no cell wall, it produces glycerol to retain water against extreme osmotic stress.

Pretty in Pink! This micro alga stocks up massive amounts of the red pigment beta-carotene (10% of its dry weight), which acts as a sunscreen, protecting it from intense light. As the richest natural source of carotenoids, Dunaliella is cultivated commercially, and sold as a “superfood”, for its antioxidant properties.

A Tolerant Extremophile? Dunaliella grows under extremes of pH, ranging from pH 1 (D. acidophila) to pH 11 (D. salina). In fact, D. salina is one of the most environmentally tolerant eukaryotic organisms known and can cope with a salinity range from seawater (= 3% NaCl) to NaCl saturation (= 31% NaCl), and a temperature range from 38 °C.

Lake Retba story and images: Sources: and

#sciencesunday  , ScienceSunday curated by Allison Sekuler , Chad Haney , Robby Bowles and guest curator Buddhini Samarasinghe while I’m painting the town red on my vacation.

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44 Responses to Painting the Town Lake Red:  A lake in the Camargue region of France, where the Rhone meets the sea, turns blood red.

  1. Wesley Yeoh says:

    yikes, is this related to red tide blooms which usually spell doom for coastal marine life?

  2. Rajini Rao says:

    No, not the same as red tide. This is both harmless and beneficial since it grows in an ecological niche that is too extreme for anything else. 

  3. Rajini Rao says:

    Mj Bedford , thanks! I did not know about the ink and food coloring use. Dunaliella is described as the most industrially important micro algae.

  4. Nandlal Shah says:

    Great capture and nice information Rajini Rao Thanks for sharing

  5. thanks Rajini Rao + Mj Bedford for great capture and the additional information!

  6. Tom Lee says:

    Interesting! Wondering what someone’d look like after swimming in the lake, redskin!

  7. Wow! Pretty incredible. Even if it is harmless though, I’m not completely sure I’d want to go for a swim in that water 🙂

  8. Rajini Rao says:

    Swimmers protect their skin against the salt with shea butter but the algae themselves are considered a health food 🙂 

  9. Great information, thanks

  10. That does not look like a strawberry milkshake. It looks like ketchup … or blooooood.

    Thanks for sharing, Rajini Rao!

  11. Kawthar A says:

    Another interesting post Rajini Rao 🙂

  12. Rajini Rao says:

    Vampire shake, Jyoti Dahiya ? Thanks, Kawthar AL ABDALLA . Hope you enjoyed the Eid celebrations!

  13. Kawthar A says:

    Thanks dear, I’m enjoying it!

    Hope you are enjoying the vacation, you have been missed! 🙂 Rajini Rao

  14. Rajini Rao says:

    Returning home on Wednesday..I’ll miss my parents 😦

  15. Kawthar A says:

    😦 sorry for that! Rajini Rao but the good part is, that you saw them & they are doing well 😀

  16. Rajini Rao says:

    Exactly, thanks Kawthar!

  17. Chad Haney says:

    I think we need to clone Rajini Rao so her parents can have a copy and the rest of us can each have our own Rajini.

  18. Kawthar A says:

    Yay!! I like the idea Chad! Though I don’t think that idea is possible. 😉

  19. Chad Haney says:

    I’m a scientist. Without dreams, we would still be cooking over a fire pit and using donkeys for transportation.

  20. Kawthar A says:

    Nope! You didn’t get my point Chad, I meant Rajini Rao is unrepeatable, or whatever is the word 😛

  21. Chad Haney says:

    But Wonder Woman is so awesome, even a bad clone would be better than most people. However, I get what you are saying. We can still dream of having our own WW.

  22. Rajini Rao says:

    LOL, absence seems to have made the heart grow fonder. I’ll be back like a bad clone penny before you know it. Actually, it is Feisal Kamil who is unrepeatable 😛

  23. Kawthar A says:

    LOL! Rajini Rao I can’t doubt that 😉

  24. Chad Haney says:

    I’m glad his lip post is out of my stream.

  25. Gaythia Weis says:

    It seems to me that there are lots of places in the world that could use the beta carotene (a vitamin A source) that could create and maintain a brackish pool of water.  It has to be nutrient poor water, apparently.  I got this far:   But somebody thought of this before me, obviously.

    Section 6:  “Thus, as much as 13.8% of the total dry organic matter in the D. salina community in Pink Lake, Victoria, Australia, was estimated to be β-carotene   The first pilot plant for Dunaliella cultivation for β-carotene production was established in the USSR in 1966 [49,50]. The commercial cultivation of Dunaliella for the production of β-carotene throughout the world is now one of the success stories of halophile biotechnology [51-53]. Different technologies are used, from low-tech extensive cultivation in lagoons to intensive cultivation at high cell densities under carefully controlled conditions.”

    Irina Tcherednichenko Something useful to do with the state of Utah?  I think that there already are pinkish spots in some of the salt flat areas.

  26. Irina T. says:

    Gaythia Weis The pinkish color of the north arm of Great Salt Lake is due to the presence of Dunaliella salina, but that’s about it. 

    Some info on commercial production worldwide can be found here:

  27. Gaythia Weis says:

    Interesting Irina Tcherednichenko !  For some reason, Google+ will not let me simply plus your comment (it says it is due to error #503)

  28. Roger Adkins says:

    Nice but but how would you harvest this?

  29. Arup Bhanja says:

    Dunaleila Salina is also grown by Nutrilite for its Multi Carotene capsule [fortified with Lycopene and Lutein]  – I consume it 3 -4 days a week and I can vouch for its effect on my eyesight – dramatically improved … A potent combo would be D. Salina with Spirulina [high protein and GLA] and I have seen my inter digital [between toes] fungal infection vanish after 10 days of consumption !

  30. Arup Bhanja says:

    Some fabulous work was done on this by Dr. Kiriac in Russia in the 1970s on farm animals and he got great results with such micro algae – ref :  especially the Xeaxanthin and  Astaxanthin

  31. Rajini Rao says:

    Thanks for the link, I’ll check it out. 

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