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Creation 41(1):47, January 2019

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‘Oldest’ biological colour discovered

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Photograph: Lannon Harley/Australian National Universityporphyrins
 A vial of coloured porphyrins (pink coloured liquid), believed to be some of the oldest pigments in the world, discovered by researchers from the ANU Research School of Earth Sciences.

Just how long can organic colours survive for? A new study claims they have survived for a whopping 1.1 billion years, more than 600 million years longer than previous similar discoveries.1 They have found intact porphyrins, ring molecules that are important components of many biological pigments, including hemoglobin and chlorophyll.

These porphyrins, from chlorophyll produced by cyanobacteria (formerly known as blue-green algae), were extracted from marine black shales in the Taoudeni Basin, Mauritania, Northwest Africa. These shales are well known for containing microbial mats full of fossil cyanobacteria.2

The rocks were crushed to powder and the molecules extracted and examined, revealing their pigmentation. In their concentrated form they now range from blood red to deep purple, but when diluted display a neon pink colouration.

The pigment would have actually appeared blue-green to the human eye originally, due to a magnesium ion in the porphyrin ring, which enables photosynthesis. The magnesium is quite loosely bound, and after a creature dies and is buried in sediment, it can readily be replaced by a different metal ion. If this is nickel, the colour becomes blood-red; if vanadium, purple, which becomes pink if diluted.3

cynobacteria
Cyanobacteria

Dr Jochen Brocks, one of the paper’s authors, said that when his student discovered the colours, he was initially in a state of disbelief.

“I remember I heard this screaming in the lab,” he said. “She came running into my office and said, ‘Look at this,’ and she had this bright pink stuff.” … Asked how he felt when he realised they had discovered the world’s oldest colours, Brocks said, “My first thought was just ‘wow’. I was just awestruck that these molecules can survive for such a long time”.4

Their assumed ‘age’ comes from being found in what is called Precambrian strata, at the bottom of the ‘geological column’ construct. Biblical creationists differ as to whether particular Precambrian rocks were Pre-Flood or Flood,5 but all agree they are only thousands of years old. Given the physico-chemical laws of decomposition of such porphyrins, their survival to the present is plausible in a biblical framework. But for them to be the claimed 1.1 billion years old stretches their survival into the realms of the impossible.

References and notes

  1. Gueneli, N. et al., 1.1-billion-year-old porphyrins establish a marine ecosystem dominated by bacterial producers, PNAS, 9 July 2018 | doi:10.1073/pnas.1803866115. Return to text.
  2. Beghin, J. et al., A palaeoecological model for the late Mesoproterozoic–early Neoproterozoic Atar/ Mreïti Group, Taoudeni Basin, Mauritania, northwestern Africa, Precambrian Research, 299:1– 4, 2017| doi:10.1016/j.precamres.2017.07.016. Return to text.
  3.  Brocks, J., paleogeochemist at Australian National University, cited in Choi, C, World’s Oldest Colors Shed Light On Ancient Life, blogs.discovermagazine.com, 11 July 2018. Return to text.
  4. Henriques-Gomes, L., Scientists discover world’s oldest colour – bright pink, theguardian.com, 9 July 2018. Return to text.
  5. See Dickens, H. and Snelling, A.A., Precambrian geology and the Bible: a harmony, J. Creation 22(1):65–72, 2008, creation.com/precambrian. Return to text.

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