Jellyfish gravity sensing organs

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Wes
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Jellyfish gravity sensing organs

#1 Post by Wes » Fri Sep 06, 2019 10:14 pm

I was going through some old slides and found a tiny specimen of Rhizostoma pulmo (a jellyfish) that I prepared back in 2005 and decided it would be nice to share an interesting feature of the organism. Jellyfish (known as Scyphozoans) can detect the direction of gravity through an organ consisting of sensory cilia and a statocyst which is a collection of tiny calcium sulphate crystals (statoliths).The cilia sense the gravitational pull on the statoliths and this helps the jellyfish orient itself.

Below are a few stacks (3-5 shots each) of such statocysts. In the higher magnification you can even see the geometry of the statoliths which seems to fit well with what I found online. The coloured background on the lower magnification images is achieved through combination of DIC and a full lambda plate (you can notice a colour gradient due to an imperfect combination of a 10x planapo and a 16/0,35 Plan DIC prism).

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BR
Wes
Last edited by Wes on Fri Sep 06, 2019 11:19 pm, edited 1 time in total.

MichaelG.
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Re: Jellyfish gravity sensing organs

#2 Post by MichaelG. » Fri Sep 06, 2019 10:18 pm

Fascinating images, Wes ... Thanks for sharing them.

MichaelG.
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tgss
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Re: Jellyfish gravity sensing organs

#3 Post by tgss » Fri Sep 06, 2019 10:19 pm

Very informative Wes, and excellent images. Thank you.
Tom W.

Wes
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Re: Jellyfish gravity sensing organs

#4 Post by Wes » Fri Sep 06, 2019 10:23 pm

Thanks Michael and Tom, I'm glad you like it.

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75RR
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Re: Jellyfish gravity sensing organs

#5 Post by 75RR » Sat Sep 07, 2019 5:29 am

Always wondered how austrailians managed ;) Most interesting + fascinating closeup.
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Wes
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Re: Jellyfish gravity sensing organs

#6 Post by Wes » Sat Sep 07, 2019 7:05 pm

75RR wrote:
Sat Sep 07, 2019 5:29 am
Always wondered how austrailians managed ;) Most interesting + fascinating closeup.
Thanks 75RR, for another closeup you can view the images in a new tab for better resolution, especially for the lower magnification ones.

MicroBob
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Re: Jellyfish gravity sensing organs

#7 Post by MicroBob » Sun Sep 08, 2019 6:29 pm

Hi Wes,
this is an especially interesting object, as well as beautiful!
Can you write a bit more about the placement of the organ in the jellyfish and how you prepared it?

Bob

Wes
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Re: Jellyfish gravity sensing organs

#8 Post by Wes » Sun Sep 08, 2019 9:16 pm

Hi Bob,
The statocysts are situated radially at the rim of the jellyfish bell (in this case there are 8 of them). The specimen (which was about 4 mm in diameter) was fixed in 10% formaldehyde, stained with an alcoholic solution of 1 % fuchsin and then mounted in Canada balsam. There was residual water which didn't mix well with the Canada balsam but now, some 14 years later, it seems fine.

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