Cnidarian explorations in Mozambique

Recently, I had an amazing opportunity to try out my brand new Foldscope that I got through the Kickstarter campaign. I was on holiday near XaiXai in Mozambique and took my Foldscope to the beach to see what I could find. Two different cnidarian species had washed up on the beach: blue bottles (also known as Portuguese man o’ war; Physalia physalis) and by-the-wind-sailor (Velella vellela). I was really excited  to see if I could find their stinging cells, also known as nematocysts. I collected my samples in some sea water and used the forceps in the deluxe Foldcsope kit to handle these little creatures to avoid getting stung.

A couple blue bottle samples in a Foldscope bag, and a cutting from one of their tentacles mounted on a slide with the PVC coverslip:


It was amazing to see the beautiful rounded nematocysts arranged on  the bulbous tubular tentacle:

And I could also watch liquid circulating inside the tentacle:


The by-the-wind-sailor was even more intriguing. I cut off and mounted a few tentacles from its underside and was astounded by their amazing colours… a mixture of yellows, greens and blues! Similarly shaped nematocysts were also present. It was interesting to compare the tightly coiled, bulbous structure of the blue bottle tentacle to the by-the-wind-sailors more relaxed tentacle structure.

It was also possible to see liquid and particles (food?) circulating inside these tentacles:

When I cut off the by-the-wind-sailor tentacles I must have cut through one of the gonozooids as I think I released some eggs:

My Foldscope is definitely coming to the beach with me again in the future!

6 Comments Add yours

  1. Mitali says:

    Wowww!!!! These are absolutely beautiful observations. I love the videos.I have never seen these organisms before.Beaches never fail to fascinate us 🙂
    Keep posting!

    1. dorithockman says:

      I’m so happy you liked the images and videos! Its great to be able to show off the Southern African marine life!

  2. Cristina says:

    Dear @ dorithockman:
    This is SO ABSOLUTELY BEAUTIFUL!!!! I have watched these images and videos several times and find them so revealing!

    Thanks for sharing them with us! Wow, wow and wow!,
    Also, can those brownish structures that move constantly be zooxantheles? I am not sure, but I have read these animals can live in symbiosis with photosynthetic microalgae .

    Your post is AWESOME!

    1. dorithockman says:

      Thank you so much Cristina! I am so happy you enjoyed my post. You are right… those brown structures could be zooxantheles… we may need an expert in cnidarian biology to confirm!

  3. laksiyer says:

    This is really dramatic. Love the nematocysts and the possible symbionts. Isnt it amazing that the Man-of-war is actually a colony of animals! Wonder what the pigment is made of, an early report suggested that these are bilins, like our own bile pigment, but dont know what is the status of that report. Would be great to see a nematocyst in action. Looking forward to your next post.

    1. dorithockman says:

      Thanks! Yes, these animals are super exciting. A nematocysts in action would be amazing!

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