Sea lettuce (Enteromorpha?) tiny companions

[Hobbyst46]

Beach submerged sandstone rocks, that are exposed to constant wave floodings, are now covered with green dense lawns of a relative of Sea Lettuce alga - actually, the genus seems to be Enteromorpha. Plucked them into a small jar with seawater, and inspected within a couple of hours.
Result: A swarming mass of tiny identical greenish swimmers, algae I believe. In between very few diatoms, some of them attached to a cilliate that is ancored to the lettuce "leaf".

The motion and phototaxis of the swimmers are shown here:
https://youtu.be/6p1lvEKnfuc
https://youtu.be/0_gfbyDkCIc

In the second link, a sparingly populated part of the slide becomes densely populated. In addition to the individual motion of the cells, collective motion moves the mass towards the center of the FOV - namely, towards the peak intensity of the light. After about 1:20 minute, I dodged the slide to the right, and the mass of swimmers reacts by slowly returning leftwise, to the center of the FOV. They are attracted to light.

A couple of hours later, having been torn from their oxygene-rich and fresh food environment on the wave-whipped beach rocks, the tiny swimmers lose their energy. Below are still images of the more static organisms. The green lettuce leaf in the second photo is out of focus.

OOPSs: the top photo is under 40X objective, not 10X. My mistake. the bottom photo is under 100X1.3 planapo oil.
Just noticed that the video clips can be viewed on youtube but not directly from the forum. Do not know why.

[75RR]

The modest looking Sea Lettuce seems to have interesting guests as I have also found.

Second image looks intriguing.

https://youtu.be/OLFsDQDztRA Diatom among swimmers
https://youtu.be/y1n_GThTDjc Phototaxis of algae swimmers

Are those the full addresses? The don't work for me.

[Hobbyst46]

Now the links do not work for me either. Disparu. I Must check and fix.

[Hobbyst46]

The modest looking Sea Lettuce seems to have interesting guests as I have also found.

Second image looks intriguing.

https://youtu.be/....Are those the full addresses? The don't work for me.

Thanks 75RR for pointing out the problem!
Those links did work on my desktop, not Android, and were large files.

I resized the videos and uploaded them to replace the previous ones. The updated links are:

https://youtu.be/6p1lvEKnfuc
https://youtu.be/0_gfbyDkCIc

Now I can view them even directly from the forum. As well as from Android tablet.
Hope this fixes the problem.

[Francisco]

Second image: Ephelota suctoria

[Hobbyst46]

Second image: Ephelota suctoria

Thanks a lot for the identification. Having read a little bit about this creature, I have more questions:
1. Is it really a protist, or a multicellular organism ?
2. Are the yellow-green "buds" on its stalk diatoms, as I thought, or are they the first phase of reproduction by division ?

[MicroBob]

Hi Doron,
thank you for sharing this nice experiment!
I can see the video links and they work. The images are visible in the text. All on windows computer.

The critters will probably react in a different way to light of different colours like red and blue.

Bob

[75RR]

Having read a little bit about this creature, I have more questions:

https://www.researchgate.net/publicatio ... uction_Pro


The sampling method looks worthwhile imitating: page 114 Journal (2nd page of the article)

Sampling. Samples were collected from Jiaozhou Bay near Qingdao (Tsingtao, 36°08′N; 120°43′E) China using artificial substrates in the form of microscope slide,
which were immersed at a depth of 0.8–1.5m for periods of 7 to 15 days to allow colonization by the suctorians to occur.

[nboyer]

Very cool looking. Would you be so kind as to tell me which eyepiece camera you're using? Cheers. -Norm

[Hobbyst46]

Very cool looking. Would you be so kind as to tell me which eyepiece camera you're using? Cheers. -Norm

Please see this post:
viewtopic.php?f=9&t=7145
The camera is a 5MP, very inexpensive.

[nboyer]

Awesome, thanks! -Norm