Marine water life: rotifers, ciliates, diatoms and bacteria 

I took another drop of water from the sea water table. This almost feels like a game. Every time I pull out a drop of water and peer into the foldscope I observe new tumbling motions, new shapes and colors.

I believe these are rotifers (or ciliates). @laks and @manup, can you confirm? I distinctly remember these creatures with legs from one of laks’s old videos describing them as the dinosaurs of the microbial world. This is my first sighting of a rotifer.

Here’s another different type. I’m curious how others identify rotifers? Is there any guide or book someone can share to ID them? I suspect this is a ciliate and not a rotifer due to the missing legs. But please correct me.

I came across this strange organism that spins round and round…

This is a diatom I think- this is the first time I’m seeing diatoms, so I’m still not sure if I’m identifying correctly. I came to the conclusion based on taking a video and it didn’t move at all. Makes me wonder if and how diatoms get from one place to another??

This I mistook for a fibre- but a video exposed it as a slow moving worm.

And finally, I came across this wonderful site which reminded me of a train station-there is so much hustling and bustling. I cannot even begin to describe all the creatures that zoom by. So much activity. So much intensity of life.

Here’s another long video. See if you can identify any of the swimming and zooming rockets.

I believe EO Wilson would hold up a bowl of water and proclaim that there is more diversity of life in this than in the entire ocean. I’m beginning to see what he was talking about.

4 Comments Add yours

  1. Manu Prakash says:

    @saad: incredible as always. You have got a tremendous “drop of water” at hand.

    – the thing with “leg like” projections in not a rotifer but a ciliate – Euplotes. The cilia like projections are called cirri and are adapted in an unusual way for walking. Strange world.. See

    You have fantastic contrast and images – you might be able to identify the species.

    – now on to the rotating ball. That’s probably a flagellate that got its flagella stuck on the surface. Since some flagella have a “rotatory motor” at its base – and net torque on a free body needs to be zero – the flagella rotates one way while the body of the organism rotates the other way. It looks so funny rotating.

    Having said that; a new report last year in PRL from Rockerfeller group (Libchaber) talked about rotating liquid crystals in a bacteria they found. Worth reading – see here:

    I also see them swimming straight in other videos; so most likely an algae.

    – the moving long worm; is most likely a chain bacteria – probably cynobacteria since it has a characteristic gate just like the oscillatoria we study in the lab. Time lapse is always amazing to see how they move. Talk to @Stefan; he has just figured out how to do traction force microscopy on them 🙂

    I love the train station analogy. For me, the most mind boggling thing is how fast they make decisions as if they always knew what they wanted to do.

    I am thinking of an idea to overlay a transparency on this video with real ciliates but a cartoon of an actual train station; kind of like “Walt Disney” Alice videos with half real and half cartoon characters 🙂 that would be a really fun project to do as a community. Any artists in the audience?

    See you in a couple of days.


  2. laksiyer says:

    Wow @Saad. These are really fantastic videos. You have a Euplotes explosion. I found a freshwater Euplotes in my pond sample ( that I still have. Those cirri really make a difference. Both cyanobacteria and diatoms have a gliding motion that is very characteristic.

    1. Saad Bhamla says:

      Awesome @Manu and@laks. You guys are right. I added the updated IDs to the iNat database as well. Also thanks Manu for the cool paper. Those are some fast bacteria motors. I found the original nature paper that discovered them-what a wonderful world:))


  3. jlpappas says:

    Hi Saad,

    Sorry I’ve been away for awhile, so I couldn’t respond until now. The diatom you picture looks like a Cocconeis. I cannot tell for sure, but the valve pictured is the pseudoraphe valve. A more detailed identification would require much, much higher magnification (using oil immersion objective at 1200X to 1400X).

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