Life in a liter of Pond water –Day 6: A mysterious dance, fun and games

Continuing from my previous post… on Day 6 post-collection, the temperature was supposed to hit freezing in the DC area and I frantically picked up my Pond water bottle to see how things were. It was a very busy microcosm as always but perhaps not for long (unless I decide to get the bottle in the house). Below the roots of the duckweed layer (there are at least three distinct species), were several small particles rapidly moving about and I siphoned out a couple of these along with a frond on to my slide.

Since my observations are on one sampling of pond water, and since I want to count as many species as I possibly can, I am using a continuous numbering system for consistency across posts.

6. Daphnia.  Arthropod–> Crustacea–> Branchiopoda –> Cladocera –> Daphniidae

daphnia

A common presence in pond water I played “Catch me if you can” with this water flea for some time. Of course I lost, but it was a fun game.

His friend though was caught at the meeting point of two bubbles and a frond (Manu something you might have thought about; using bubbles to trap small critters). Anatomical details were visible and there was perhaps also a brood pouch.

7.  Metazoa–>Protostomes –>Spiralia–>Platyzoa–> Rotifera

rotifer-feedingA transparent rotifer. This one was more transparent than the previous rotifer I observed, although it might just be the same species. The rotifer’s feeding mechanism however was very apparent. The mouth leads in to the grinding pharynx or the mastax and is hard at work in this video.

8. Swarming flagellate of unknown provenance displaying synchronous disaggregation.

flagellate

The hands-down star of the day. Along the edge of the duckweed frond were many groups of identical cells involved in an intimate dance and then to my surprise they burst out like a firecracker in all directions. What might this be? I took it to my local expert (L. Aravind) and he pointed to me that it was a flagellate with two flagellae emerging from a depression, but even he had never seen such a behavior. I knew for one that this is quite an uncommon observation. A few speculations came out from the discussion.

  • These are freshly divided cells that were released. However, there didnt seem to be any active division or number increase as far as we could see.
  • My favored hypothesis was the second one that this could be some kind of transient crowding behavior. Kinetoplastids (another flagellate) are known to have a crowding behavior, but nothing like this one. Could they be sensing the environment and then coming to a common focus and exchange information about say nutrient concentration. It is likely that in such scenarios, kin crowd with themselves. How do the kin find each other then?

So many questions and no answers yet. If you know of this phenomenon (Manu’s term is apt: Synchronous disaggregation) or know of any experts who might have an explanation, it would be great. Whatever it is, this is not common knowledge and needs a careful study and a biological explanation. I hope some of you also spot this in your explorations.

10 Comments Add yours

  1. Matt.Rossi says:

    @laks, you’re making me think I need to return to some freshwater hunting. That water flea is quite an interesting specimen.

  2. Saad Bhamla says:

    @laks – The last video is a spectacular show! I love how the cells just dispersion in an explosive manner!
    Super fun to watch over and over again : )

  3. Ivan Rey says:

    Whoa!! Great!
    Regarding the last video, if you were to play it backwards it would look like the dictyostelium discoideum aggregation behavior, though d.d. lives in soil and crawls.
    Perhaps they were trying to aggregate but then decided not to…

  4. Manu Prakash says:

    @Laks: I am frozen in shock – no I really am. What an incredible finding. The group activity is muh higher speeds than any colonial/social activity I have ever seen. Usually; groups and collective behavior is often an act of millions of cells – not just a few and the way they disperse is as if it was just decided it’s time to go. Multi-cellular behavior in a ciliate/flagellate.. With a very clear decision when to decide not to hang out.

    I am left speechless. You have to pursue this; please treat your culture like gold.

    Few questions:
    1) would you see them come together again just like they dispersed?
    2) is this something where a burst of cell division happens; followed by dispersal phase or can they come back together again.

    I have a simple proposal for an experiment to test the second clause above. I have recently been able to trap ciliates and swimming microorganisms in general in individual droplets. This is very helpful since I like to observe the same thing for a long time. I just put a drop of water with the organisms of interest. Now I take another slide and keep breaking this drop into smaller and smaller drops. I sometimes suck out the small drops or just leave them all. Once I have a sufficiently small droplets or I have enough of them; I put a cover slip and seal the same. I keep the drops at distance – so they don’t merge.

    If you had the group in one droplet; after dispersal; would they ever merge? That would be a valuable information to know to understand the evolutionary context of what you just saw.

    In my life; I have spent many many many hours looking through a foldscope. This is one of the most fascinating observation. Kudos and congratulations..

    Now; back to look at my own pond aquarium (I specially got it from Tahoe – with some surprising bugs)..

    Cheers
    Manu

    Cheers
    Manu

  5. laksiyer says:

    Dears @Matt @Saad @Ivan @Manu. I am still sort of mesmerized by what I saw and have been talking to whoever I know about it for identification and prior examples of such observations– no complete answers yet. It is amazing to see that there are several mysteries still remaining to be solved in biology!! @Manu I will definitely try to reproduce it, but pond water samples are extremely fickle and I worry that this is it for now. I wanted to see if they aggregate but didn’t see anything obviously. I am keeping my eyes wide open. I love the droplet idea and I am definitely going to try it.

  6. Manu Prakash says:

    @Laks: I will upload some instructions on making water droplets in oil; for long term ciliate measurements.

    In the mean time; I am assuming your pond water is happy and doing well – so you have more observations still of the same phenomena.

    Have you coined a name for it – what about “ciliate fireworks”.. 🙂 more seriously – synchronous dissaggregation?

    Cheers
    Manu

  7. laksiyer says:

    Yes Synchronous disaggregation it is. The pond water has been holding up and I am searching hard to find these chaps again. This time I am better prepared (whatever that means). Looking forward to your instructions.

  8. Manu Prakash says:

    @Laks: I met Nicole King (UC Berkeley today); and showed your movies to her. She was very excited (I have requested her to join Foldscope community) – and she shared this series of papers Ruiz-Trillo lab (http://www.multicellgenome.com/publications.html); specially

    http://elifesciences.org/content/2/e01287

    {Regulated aggregative multicellularity in a close unicellular relative of metazoa

    Arnau Sebé-Pedrós, Manuel Irimia, Javier del Campo, Helena Parra-Acero, Carsten Russ, Chad Nusbaum, Benjamin J BlencoweCorresponding Author, Iñaki Ruiz-TrilloCorresponding Author
    Institut de Biologia Evolutiva (CSIC–Universitat Pompeu Fabra), Spain; Universitat de Barcelona, Spain; University of Toronto, Canada; Broad Institute of Harvard and the Massachusetts Institute of Technology, United States; Institució Catalana de Recerca i Estudis Avançats (ICREA), Spain
    DOI: http://dx.doi.org/10.7554/eLife.01287
    Published December 24, 2013
    Cite as eLife 2013;2:e01287
    – See more at: http://elifesciences.org/content/2/e01287#sthash.7pEBHYYr.dpuf}

    I will look at all th emovies carefully; but indeed you might have found something very interesting and it would be valuable to find them again 🙂

    More on this will follow; as I read this paper carefully; but I could not contain my excitement.

    Thanks to Prof. Nicole King for pointing this out.

    cheers
    manu

    1. laksiyer says:

      Dear @Manu. I am well aware of Nicole’s studies on the choanoflagellates and it will be great to have her on board. Will look at the movies and the other papers on Capsaspora carefully. I still have the same pond culture, but haven’t found the flagellates or their aggregative behavior again. Will keep looking of course. More after the papers.

      1. laksiyer says:

        On a different note. I now recollect an old blog post that we made predicting some interesting extracellular enzymes in Monosiga that might be involved in promoting multicellular states. This was based on Nicole’s observation of a sulfonolipid made by a bacterium being involved in the aggregated state in Salpingoeca.

        http://jivarahasya.blogspot.com/2012/09/origin-of-multicellularity-bacterial.html

        I wonder when frugal tools would invade the chemical world and we can probe the vast unknown for interesting molecules.

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