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Perspectives From Puddles

Added on: 14-July, 2023

By Mitali Patil

My first peek into the world of ‘developmental biology’ was years before I knew that such a field of study existed. Thanks to Foldscope – an origami paper microscope and a humble puddle on a sea beach in Mumbai that I got excited about looking at innards of all kinds of eggs.

I was in the first year of my undergrad when I got my hands on a Foldscope and the puddle that I just mentioned was the very first sample I looked at.

It was a lively sample with lots of ciliates, bacteria, algae and my favorite – colonial vorticella. I enjoyed watching the colony contract. I could watch them for hours!

Sadly, after a few days the ecosystem shifted and the colonial vorticella got wiped out.

That’s when I turned my attention to the annoying fast swimming things. The reason I call them annoying is because I remember spending hours trying to catch these tiny buggers who turned out to be crustaceans. They looked majestic under the foldscope.

However, they had something more than their majestic looks to offer – EGGS!

The crustaceans were carrying eggs in their pleopods. I gasped and somehow separated the eggs to take a closer look. This was my first time looking inside an egg and it was absolutely insane!! The feature that I noticed right away was the dorsally placed heart which was beating really fast. The appendages, the compound eyes, the twitches and flows in the gut, everything about it was just mind boggling!

I learnt a lot that day – starting from the fact that crustaceans lay eggs, carry them also and also externally fertilize them. Here’s a video of the crustacean egg I took almost 7 years ago.

The beauty of small aquatic organisms is that they have almost transparent bodies and transparent eggs.

These creatures are present all around us and there is tons of biology to learn from all these puddle dwelling beings.

In addition to tiny things, there are also larger organisms in puddles that can be just spectacular to look at. Few weeks back, I spotted a pair of frogs in the puddles on NCBS campus and soon noticed that the puddle was full of frog eggs.

Although I have studied developmental biology for a semester and learnt about frog egg development in detail, I had never actually seen a frog egg outside the complicated textbook diagrams. It was mind boggling to see so many of them and also be able to tell that they were still at a very early stage. I could see the animal and the vegetal pole of some of the eggs just by looking at them without any lenses. I had to bring these eggs home and set up a time lapse to watch them develop.

Here’s a four hour long time lapse I took with my phone and a clip-on macro lens which my friend Girish recently gave me.

I’ve captured the event when the animal pole engulfs the vegetal pole and the neural tube starts forming on the dorsal side. These eggs somehow reoriented themselves no matter how hard I try to pose them right for the video. They would orient such that the animal pole is upwards and the vegetal pole downwards – which is also where all the action was visible. I had to do what fancy individuals would call “inverted microscopy” which means that I had to put the lens underneath the slide and look at the eggs from the bottom.

Here’s the video:

The same pond where I found these frog eggs, also has tons of snail eggs throughout the year which I often keep an eye on. I’ve brought some fish and snails home from the pond so that I can watch them all the time. Surprisingly, I also ended up getting a few planaria which are also thriving.

Here’s a video compiling all the stages of the snail eggs I’ve captured so far.

All it took to make these videos is my phone, a foldscope, a clip on macro lens and a couple of sleepless nights to keep a watch on the time lapses.

Something that I learnt in my early days of going around looking at puddles and writing blogs about my observations is that most of the biology is outside the laboratories and textbooks. As an undergrad, the amount I was learning by putting everything under the foldscope was by any measure teaching me more things than a textbook and college syllabus – not just about biology but microscopy, photography and of course the art of jugaad. I also learnt the importance of documenting and revisiting observations made in the past. Observations can either be momentarily exciting or mundane but the value lies in the process itself. They are like building blocks – you can put them together and build bigger pictures of your understanding of any system and this, I’ve learnt,  happens over time.

The colonial vorticella I observed 7 years ago continues to still fascinate me and it is always for different reasons because I learn new things over time. I recently learnt how the calcium dynamics make the colonies contract and I had no idea it worked that way!

A keen eye, simple tools and the curiosity to take a closer look at things is mostly what it takes to at least start doing science anywhere be it in a lab, at your home or out in a field.

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