Strange Copepod behaviour

Images made through a microscope. All subject types.

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Mitch640
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Joined: Sun Aug 15, 2010 1:43 pm

Post by Mitch640 »

Very interesting. I have tried catching fresh water cyclops in my aquarium with absolutely no luck at all. While I can barely see them, they had no trouble at all sensing the tip of my turkey baster pipette.

When I bought a stereo microscope and collected some pods in a small clear cup, they then had no trouble at all dodging the tip of a 5ml pipette as it slowly tried to sneak up on them. I then put the cup water into sections of a white ice cube tray, to increase my chances and decrease theirs, but again, they were very quick and somehow sensed the tip of the pipette as it got near. In the end, I think I just wore them out and they gave up, or I never would have caught one.

I don't think the red eye can see anything other than light, so they were probably listening to the thump of my heartbeat transferred through the pipette and into the water. It's all I can imagine. :)

phytoplankton
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Joined: Sat May 28, 2011 11:38 am

Post by phytoplankton »

Pipettes create a pressure wave, visible with schlieren or shadow photography, when they suck in the water. Some copepods are extremely sensitive to this because some predator fish use a sucking motion to capture prey.

A pipette with a wider opening might help. But I think you were on the right track with the ice cube trays. Sometimes the best way to isolate the specimen is to scoop them up in a relatively large volume, then repeatedly divide up the sample until you have a small enough sample size that contains the organisms you want. Pouring off the fractions or a burette might work, or there are plankton sample dividers made specifically to divide water samples equally.

Harald
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Location: Steinberg, Norway
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Post by Harald »

Hi,
What can I say :shock: ??
This is just some amazing shots. I need a darkfield condenser, and I need it now. This is just great inspiration to me :smt038
Kind Regards
Harald

Lier Fotoklubb / NSFF
AFIAP / CPS
BGF / GMV
http://www.500px.com/blender11

Wim van Egmond
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Joined: Tue Aug 15, 2006 9:28 am
Location: Berkel en Rodenrijs, the Netherlands
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Post by Wim van Egmond »

But it is quite easy to make yourself with a bit of cardboard.

http://www.microscopy-uk.org.uk/mag/art ... trast.html

Wim

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