This Microscopic Ciliate Was Found on a Copepod in France - Observation of the Week, 11/2/20

Our Observation of the Week is this Trichodina domerguei ciliate, seen in France by @plingfactory!

“Taking samples for a microscope is like a surprise bag,” says Michael Plewka, “you never know what you will find!” Focused on marine biology and coral ecology in college, Michael is now a high school teacher in western Germany and has changed his area of study from marine to limnic life thanks to an artificial pond he and his students monitor. “So now I am studying the life  of small organisms living in water, soil and mosses in Germany and other European countries,” he tells me, and he works with other microscopy enthusiasts at organizations like Berliner Mikroskopische Gesellschaft.

And of course when Michael travels, the microscope equipment comes along. “Whenever I have holidays my focus is either on looking for small critters in tropical marine environments,” he says, “or taking my microscope somewhere and watching the organisms that I can find.”

You can find the most interesting organisms in the most boring environments where you don't expect to be life at all, like for example old industrial buildings. The vicinity of a nearby-airport in our region has some of the most fascinating and rare microscopic organisms.

In May of 2014, while on holiday in France’s Bretagne (Brittany) region, he took a plankton sample from a pond in the city of Bourg-Blanc. “The pond itself was not very spectacular,

[but] interestingly enough it turned out that there were similar organisms (same genera) as in ponds in Germany, but different species. And then I found some small critters moving around a copepod. I knew from our observations in our school pond that a similar protist (Trichodina pediculus) lives as a parasite on Hydra

While he didn’t have the correct literature with him at the time (rotifers are his specialty), Michael later identified the tiny ciliate as Trichodina domerguei, based on its number of denticles. Like other members of this genus, Trichodina domerguei attaches itself to a host (often fish) which it uses primarily as a substrate - its mouth faces out. Usually the ciliates don't harm their hosts, but they certainly can, especially if they attach to a sensitive part of the animal. You can check out Michael’s photo of the copepod host here

Michael (above, in The Netherlands) joined iNat at the urging of his colleague @rotiferologist, and has since been helping others identify their rotifer observations. “Taking adequate images from such small organisms is not that easy, so it is also not always easy to ID the specimens based on these photos alone, especially when it comes to the species level,” he says, “[but] thanks to the ever increasing power of smartphones which can be used at a microscope the situation might get better in the future.”

To Michael, “iNaturalist is a chance to communicate with people  who are interested in nature from all over the world. 

In times where it is necessary to be conscious of the fact that the activities of people on one continent have an effect on the life of people on other continents, iNaturalist is a great tool to connect people and to see that like-minded people are working together.

- Take a look at Michael's other photos on his website!

- Michael recommends this website as an excellent resource for identifying protists.

Posted by tiwane tiwane, November 02, 2020 23:10



What a gorgeous ciliate! Thank you Michael!

Posted by susanhewitt 3 months ago (Flag)

Beautiful image, Michael! Good to see an image of you, as well. I like the sampling pole. :)

Posted by bdstaylor 3 months ago (Flag)

Interesting! Am I the only one who has trouble figuring out its head and tail whereabouts? O_o! Thank you so much for sharing the websites resource for identifying protists.

Posted by sunnetchan 3 months ago (Flag)

Who knows? You may be the selected lucky one in next week. Excus me... I'm going to train my sea monkeys to do some trick! @jameson_nagle ;-p

Posted by sunnetchan 3 months ago (Flag)

Hey folks, please keep the conversation focused on the blog post itself, thanks!

Posted by tiwane 3 months ago (Flag)

Wonderful! You mention "when Michael travels, the microscope equipment comes along." I am wondering what sort of equipment he takes along. He has some amazing photos. I am curious about how to get the best photos on the road/in the field, and are there any suggestions regarding smartphone equipment (setups and or lenses) and getting the best photos with such equipment.


Posted by jholmes 3 months ago (Flag)

Fantastic photo! I'm amazed by the contrast and the detail. Thank you! : )

Posted by claudia_ma 3 months ago (Flag)

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