Living stromatolite found in Ireland!

October 14, 2011 • 1:30 pm

Since I’ve posted about stromatolites before, I hope that readers remember what they are.  As a refresher, though, they’re the oldest convincing traces of life on earth: fossilized colonies of cyanobacteria (“blue-green algae”) which date back 3.5 billion years ago—only a billion years after the Earth had formed.  While fossilized stromatolites have been found in many places, living ones can exist only in a very few places on Earth.  Wikipedia notes:

Modern stromatolites are mostly found in hypersaline lakes and marine lagoons where extreme conditions due to high saline levels exclude animal grazing. One such location is Hamelin Pool Marine Nature Reserve, Shark Bay in Western Australia where excellent specimens are observed today, and another is Lagoa Salgada, state of Rio Grande do Norte, Brazil, where modern stromatolites can be observed as bioherm (domal type) and beds. Inland stromatolites can also be found in saline waters in Cuatro Ciénegas, a unique ecosystem in the Mexican desert, and in Lake Alchichica, a maar lake in Mexico’s Oriental Basin. Modern stromatolites are only known to prosper in an open marine environment in the Exuma Cays in the Bahamas. Stromatolites can also be found in the hyper-saline inland lakes on San Salvador Island, Bahamas.

According to the BBC, though, living stromatolites have just been found in a place frequented by bazillions of tourists—the Giant’s Causeway, a formation of basaltic hexagons in Northern Ireland:

In a small grey puddle tucked into a corner of the world famous Giant’s Causeway, scientists have made an extraordinary find.

A colony of stromatolites – tiny structures made by primitive blue-green algae.

Stromatolites are the oldest known fossils in the world.

The tiny algae or bacteria that build them are also thought to be the most ancient life form that is still around today, after more than three billion years.

What makes the discovery in Northern Ireland so remarkable is that until now these structures have been found mainly in warm and often hyper saline waters which discourage predators.

The stromatolites in the Giant’s Causeway are in a tiny brackish pool, exposed to the violence of waves and easy prey to the animals that are already living amongst them.

The find was purely accidental, suggesting that perhaps living stromatolites occur in other places but simply haven’t been found. It’s also a very young colony—only one layer thick.  The ancient fossilized ones (see below) are composed of many layers of bacteria separated by sediment.

The colony at the Giant’s Causeway on Northern Ireland’s wind-swept north coast was found by accident.

Scientists from the School of Environmental Sciences at the nearby University of Ulster were looking for very different geological formations when Professor Andrew Cooper spotted the stromatolites.

“I was very surprised”, explained Professor Cooper.

“I was walking along with a colleague looking at something else. Out of the corner of my eye I spotted these structures which, had I not seen them before in my work in South Africa, I probably wouldn’t have known what they were.”

The colony is very young, just a layer thick, so it’s recently formed. One thing that is puzzling scientists is why its chosen this spot.

“There is some unusual set of circumstances that occurs just here that doesn’t occur even 10 metres away along the beach,” said Professor Cooper.

The place is sure to be flooded with gawkers looking at this ancient life formation, so I hope the local authorities are doing something to protect the area.

Here are living stromatolites in Shark Bay, Australia:

And some fossils, clearly showing the layers:

31 thoughts on “Living stromatolite found in Ireland!

  1. Maybe I’m nitpicking, but I thought the stromatolites is the structure built up by the accretion of successive layers of bacterial growth. So what does it mean to talk about a stromatolite only one layer thick? How does this differ from an ordinary bacterial film?

    1. Exactly. How do you even find a one layer thick stromatolite, it’s nothing more that a biofilm. Unless they mean only the top layer was alive, but that’s the case for all stromatolites. I don’t get it.

      1. Maybe he saw the sheen of the layer and recognized what it was? At any rate if they took a small sample and looked under a microscope then there can be no disputing the claim.

        1. Gregory’s point seems reasonable, and in that case it doesn’t matter that they looked at it under a microscope. Or maybe there are certain species of stromatolite-forming cyanobacteria, and the discoverers proved that the species found were indeed stromatolite-forming? I hope somebody who knows something about this can chime in.

      1. OK, but we don’t call it a reef until it has some larger structure to it. My (perhaps mistaken) impression was that stromatolite is to cyanobacteria as reef is to coral.

        If you’re saying that “stromatolite” is just a synonym for (some particular species of) cyanobacteria, then what do you call the structure built by those bacteria? What’s the equivalent of “reef” for cyanobacteria, if not “stromatolite”?

    2. There’s a bit more info in the article, but not much.

      Stromatolites are formed by blue-green algae that excrete carbonate to form a dome-like structure. Over thousands of years these build up into a hard rock that continues to grow.

      So maybe the new found colony shows one layer of carbonate?

          1. New Zealand = North and South Island, Australia = West Island according to the Kiwis, so is Ichthyic a transplanted Aussie?

      1. Dom, I was thinking of you when I posted that. 🙂

        I like BPoD. And despite its title, posts seldom appear every day, which is nice for those of us who simply can’t keep up.

  2. Samuel Johnson when asked if The Giant’s Causeway was worth seeing is supposed to have replied – “Worth seeing, yes; but not worth going to see.”

    1. 1) Not all niches are totally eliminated.

      2) Creatures with populations of six to seven billion are fairly easy to make extinct. Single cell creatures with populations of billions upon billions are really hard to get rid of.

      1. uh, just in case you didn’t realize, he was doing a satire of an old creationist canard:

        “If evolution is true, why are there still monkeys?”

        oh, and since you answered…

        uh, no, those are actually not good answers to the question.

        Would you like to understand what the actual answer are?

  3. Hi there, I know it is from wikipedia but anyway Lagoa Salgada is in Rio de Janeiro state and not Rio Grande do Norte. Cheers.

  4. Trust Ireland to be full of marvelous little green creatures 😉
    I’ve always found it amazing enough stromatolites could still exist in Australia, but I had no idea they were found anywhere else. Great stuff

  5. All very chatty but please could you compare the photos with those for Nostoc on a wonderful website called algaebase ( This Nostoc is having a nice quiet time as it often does around our coasts and anywhere that is wet. It must have been near perfect for its role in life as it has indeed hardly changes form through most of biological time.
    Stromatolite it was not as many of your readers obviously thought.

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