A day in the life of the Hydra

Images made through a microscope. All subject types.

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Brian Matsumoto
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A day in the life of the Hydra

Post by Brian Matsumoto »

This is my longest video and one that required the most preparation. I had cultured some brown hydra and wanted to record a movie of this freshwater jellyfish capturing and ingesting prey. I made a small aquarium slide and placed three hydra in the tank and added some small freshwater crustaceans. The first part of the video shows the hydra whose oral side is facing "north". The prey was placed on the wrong side of the tank, the "south-side" of the hydra. This was a classic example of operator error, having forgotten that compound microscopes invert the image.

In any case, the hydra adjusted their bodies so that the tentacles were facing south. It made me wonder if they had sensed that there was food and contorted their bodies to maximize the chance of capturing the organism. In any case, the video ends with the crustacean being ingested.

The video is rather long--about 7 minutes and you can expand it and view it full screen.

Let me know what you think of it. My technique needs more work and I will keep plugging away.

http://www.youtube.com/watch?v=dl_oVns2oa8


Brian Matsumoto

Pau
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Post by Pau »

:shock: Excellent film, Brian! =D>

The sequence when the tentacle catches and paralizes the prey is really impressive

About the technics, I see chromatic aberration at the image borders. What kind of equimment did you use?
Pau

rjlittlefield
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Post by rjlittlefield »

Very nice!

The ingestion sequence starting at 3:45 is remarkably clear and explanatory. (I'm imagining a very pudgy python swallowing an antelope...)

Is this original speed, or did you have to time-lapse it?

Also I find the music to be a perfect match to the action. Can you say something about how you find and fit it?

--Rik

Brian Matsumoto
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Post by Brian Matsumoto »

Thank you for looking Pau,

The optical aberrations at the periphery are probably from the projection eyepiece. I had been experimenting with different systems and I am sorry I selected this specific one. Normally, I do not have intervening optics on my Olympus BX series microscope but in an attempt to obtain a variable magnification I tried something new. This adapter will no longer be used.

The scope is an Olympus equipped with a 2X objective. The condenser is a dry "darkfield" type and the camera is a Sony NEX-6 camera. The video was set for HD 60p.

Brian

Jacek
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Post by Jacek »

:smt038

Olympusman
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Hydra

Post by Olympusman »

Very nice video. My lab assistant, Duchess the cat, stopped by and was absolutley captivated by your video.
Hydra are always fascinating because they appear to have some minor form of intellect that tells them how to position their prey before ingesting them.
Because they reproduce by budding ( self-cloning), it is said it is a perpetual roganism. In effct, the hydra you have may be thousands if not millions of years old.
Michael Reese Much FRMS EMS Bethlehem, Pennsylvania, USA

RogelioMoreno
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Post by RogelioMoreno »

Excellent video!

Rogelio

Brian Matsumoto
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Post by Brian Matsumoto »

Rik:

The video was uploaded to Youtube and once there you can go to video manager. Uploaded videos have a thumb nail and to the right of it is a button labeled edit. Just to the right of that button is a speaker icon and the words "Add music". When you click on those words you will see a box with Featured Tracks which lists the Top Tracks. Clicking on the music title gives you a preview of the song. You can use the pull down menu which extends from the Top Tracks to select music of specific genres. You also have a search command that allows you to find songs of approximately the same length as your video. When you highlight the song of your choice, you hit the save button and the audio is merged with the video track. For me, finding the right music was a matter of playing several audio tracks and picking the one I found most pleasing. At first, I had not added the audio tracks, but the addition of music makes the video more pleasing.

I've just started exploring YouTube and I am sure my response will seem too basic for the power users. But it is a good starting point.

My movies are recorded as HD videos, 60 frames per second, progressive. When loaded onto Final Cut Pro X. I have the option of either speeding up or slowing down apparent motion. As you probably noted, I varied the frame rate of the playback. Hydra are not the fastest organisms and I sped up portions of the track so that the action appeared "live" I had doubled the frame rate in some cases and this helps makes the ingestion process more obvious.

I acquired a darkfield condenser from Bunton Instruments that is designed to cover the field seen by 2X objectives. This will be used in my next video. Hopefully, I can improve the "capture" phase of the movie with this.

Brian

rjlittlefield
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Post by rjlittlefield »

Many thanks for the info. The description was a perfect level for me, since I had no clue about those YouTube audio features.

--Rik

carlos.uruguay
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Post by carlos.uruguay »

A work of art.
Thank you for sharing it

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