Microfauna around lichens

Mar 09, 2020 • 10:00 PM UTC

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TCIS Outreach

We are a group of students, volunteers and staff working with TIFR Hyderabad's Science Education and Outreach program: http://www.tifrh.res.in/~outreach/

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My friend Chandrika brought me a sample of these beautiful lichens from Bangalore, with the hope of finding Tardigrades in them.

We soaked one of the samples in RO water.

After 5-6 hours, with great enthusiasm I started to hunt for tardigrades but no luck! In every single sample I observed, that very familiar guest – a rotifer – came into my field of view. Over the next week I saw in this sample different types of ciliates like Colpoda and Paramoecium.

Then the water dried up. So I added some more RO water and continued observing the water drops. By this time the lichens had started to disintegrate. And then, I saw this purple-coloured thallus!

One of the ciliates seems to be undergoing binary fission! Can anyone help to identify it?

What could this be? Slowly moving like amoeba – exactly how I imagined amoeboid movement in my school days! An amoeba — how did it get into lichens growing on a tree trunk??!!

More rotifers and ciliates! This time a nematode joined in attendance under my Foldscope.

After two days I observed a moving black structure which at first resembled an insect, then I noticed long blunt pseudopodia emerging out of one end! Could it be an Amoeba in a cyst? Internet search hinted it could be a testate Amoeba. Happily, then @laksiyer told us it is a type of testate amoeba called ‘Difflugia’.
Were testate amoebae really found in Lichens? Yes! Said a paper on lichen microfauna from Lithuania , which also suggested the title of this post. Thank you, Ingrida Šatkauskienė!

Along this journey I noticed two remarkable incidents.

The first was a ciliate which had a fine filament trailing behind it. Was it a fungal filament from the lichen, stuck on the cilia of the ciliate?

The second was a dynamic drama between a rotifer and ciliates! In this video you see a rotifer rapidly grabbing and swallowing ciliates. Do you think the ciliates are attacking the rotifer too?
Though I did miss the Tardigrades, I thoroughly enjoyed the wonderful new discoveries hidden in this sample!
Cheers!
Ashalatha