It started with my wondering about the pictures of tardigrades on the new foldscopes. Called the “world’s most indestructible creatures”, I learnt that these hardy champions survive for 30 years without food or water. They have endured extremely cold, irradiated journeys, riding on the outside of space-ships… and you can find them just by soaking lichen in water!
Since lichen and moss are not so common in the city, I sought inspiration in the delicious Hyderabadi biryani. A key spice in cooking biryani is patthar phool / dagad phool / kalpasi, which is said to be a dried lichen, Parmotrema perlatum. Looking closely at this sample of the lichen I detected in it some bryophytic and fern-like bits too.
The rest was pure serendipity. I soaked the dagad phool in mineral water and let it stand for two days. Then I observed a drop of this water under a foldscope.
All the next six videos are taken with my iPad.
Amazing! The water drop contained numerous tiny microorganisms moving very fast. From their quick, jerky movements I guessed that they were not tardigrades but most likely protozoans.
Learning to focus
The next day I had a lucky meeting. We visited the Nizam’s College Zoology department where Nageswara Rao and Srikanth Bestha have been using the foldscope to study water samples around Hyderabad. Srikanth taught me a wonderful video technique that involves reducing the intensity of the LED, adjusting the light angle, reducing the brightness of the camera screen, and using slow motion video. A video of the same slide taken by Srikanth shows how effective is the technique.
Now we could see these kidney-shaped organisms which contorted their shape while swimming. They had colourful food vacuoles inside them. Checking on the internet we thought they must be Colpoda.
After a week the dagad phool culture was almost dried out with only little water remaining in it. I squeezed the material gently and collected the water drops on a concave slide. Still no Tardigrades, and only a few Colpoda were visible but I found three beautiful Bdelloid rotifers! Another nice result using my newly learnt video technique. 🙂
I added some water to the material, and two days later I observed a drop of this water. The Colpoda were back in action, moving around happily against a grainy background, which may be composed of bacteria, protozoa and debris.
Finally after ten days I observed the material, which was again drying out. I squeezed it and collected the water drops. Interestingly, the Colpoda were still alive. Quite a few were enmeshed in the decomposing dagad phool, in resting stages, in which they move around in tight circles. This movement is an identifying characteristic of Colpoda.
I observed the watery part of the slide again after twenty four hours. There appear to be many different kinds of microbes, busily exploring that tiny water drop.
Tardigrades may hold the championship title, but almost as astounding are the rotifers and Colpoda and so many others, how they survive almost complete desiccation and burst into activity at the least touch of water. It was a most enjoyable experience exploring the dagad phool ecosystem; and I hope to continue to learn better techniques to make videos with the foldscope.
with Debashree, Chandrika and Jayashree