Some amoebas

Images made through a microscope. All subject types.

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dy5
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Joined: Sun Feb 07, 2010 7:50 pm
Location: College Park, MD

Some amoebas

Post by dy5 »

These are all from my neighbor's backyard pond. The IDs are all tentative - any help with that would be much appreciated.

DIC and high-speed flash (the latter hardly necessary to freeze movement of these subjects).

1. Arcella sp. Empty tests are common, but I've much less frequently seen one with the owner at home. Does anyone know if the symmetrical air bubbles are normal?
Arcella for post.jpg
2. Vampyrella sp. This one seemed to be carrying debris stuck to its body. A few of the pseudopods like the one on the left seemed almost feather-like.
Floral amoeba post.jpg
3. Parachaos sp. The cytoplasm is filled with glistening crystals of various sizes and shapes. The amoeba is getting ready to engulf an algal cell, Golenkinia sp.
Attachments
Amoeba munch for post.jpg

Bruce Taylor
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Re: Some amoebas

Post by Bruce Taylor »

Bubbles are indeed normal in Arcellidae. Gas bubbles enable the organism to lift itself from the substrate into the water column, where it can float to a new location. See: https://onlinelibrary.wiley.com/doi/abs ... lAQSst8Ysg

Note that the Arcella discoides in that article is now Galeripora discoides. The old genus has been split, and we now have to look a bit more closely to differentiate Arcella from Galeripora.
It Came from the Pond (Blog): http://www.itcamefromthepond.com/

Lou Jost
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Re: Some amoebas

Post by Lou Jost »

Picture #3 looks like something out of a unicellular nightmare.

dy5
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Re: Some amoebas

Post by dy5 »

Thanks, Bruce. Buoyancy control - that's a clever adaptation. I'm learning that amoebas are so much more than moving, morphing blobs.

Lou, the nightmare scenario is about right. When it was some distance away, that amoeba seemed to change course to go toward the algae. How could it 'know' that food was in that direction? Of course, the turn could have been random, but I've several times seen that kind of seemingly 'directed' behavior by various large amoebas.

Lou Jost
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Re: Some amoebas

Post by Lou Jost »

IPerhaps they are more sophisticated predators than we suspect. They could possibly notice chemical gradients, or pressure waves, or even electrical fields.

Bschnitzer
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Re: Some amoebas

Post by Bschnitzer »

Or very slight changes in light from a particular direction?
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