A while ago, I posted a question about musicians with weaponized instruments guarding a palace. I thought it would be interesting if they also had access to some sort of poison that they could use to poison someone (with poison in the drink for instance), if secrecy was more necessary.

I came up with this idea of the musicians playing music to the poison-making microorganisms to grow them. (EDIT: The question has been expanded and is now asking if this is possible for ANY organism.)

Now, I also found this interesting question, with an answer stating various energy sources (pressure, heat, etc.) that could be transformed to give usable chemical energy to an organism. However, specifically sound energy was not mentioned.

Could sound waves be theoretically transformed into energy for an organism for the purpose of growing these organisms? How would this work?

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    $\begingroup$ Note that food needs to provide both energy and materials with which to build the body from. $\endgroup$ – DKNguyen Oct 8 '20 at 23:06
  • $\begingroup$ (Ultra) sound is used to destroy kidney stones, so yes, it can and does transfer energy. Not a whole lot though; it works best when focused, as in this schemtic. $\endgroup$ – Peter - Reinstate Monica Oct 9 '20 at 7:07
  • $\begingroup$ Nice way to capture energy, but you also need a way to capture carbon. $\endgroup$ – João Mendes Oct 9 '20 at 11:10
  • $\begingroup$ If you use "the drink" as material, then the in general peaceful organism could be caused by a sound range (in nature used by organisms enemies to detect it) to start the defensive mechanism of poison production... $\endgroup$ – Allerleirauh Oct 13 '20 at 5:33

Sound waves are made of pressure variation in a medium.

Pressure waves can produce work, and if they can produce work they can produce energy.

That's precisely how a piezoelectric transducer works, transforming a sound wave into an electric signal.

In principle a piezoelectric crystal can be used instead of sunlight or glucose as energy source for the cell. You just need the right molecule to capture that energy.

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    $\begingroup$ Add interference patterns of music, which are the area's where multiple (sound)waves meet and have a spike in potential energy and you could even target someone specific in the audience on a specific place with the acoustics. $\endgroup$ – Trioxidane Oct 8 '20 at 17:28
  • $\begingroup$ @Trioxidane Does that mean if they had the victim ingest the microorganisms beforehand they could have the music during the concert slowly grow the microorganisms and poison the victim? $\endgroup$ – DanPar Oct 8 '20 at 18:16
  • $\begingroup$ @DanPar assuming the person eats it... I guess so. I'm only now thinking about the flesh dampening soundwaves and I don’t know how that works out. But it might be easier to have some chemical activate under pressure or electricity, making it easier to transfer the sound into something deadly either directly or under certain crystals that produce electricity under stress (that really exist). $\endgroup$ – Trioxidane Oct 8 '20 at 20:25
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    $\begingroup$ It should be noted that microorganisms are substantially smaller than the wavelength of most music sounds. This means that the pressure gradients across the organism would be very small, and the likely effect of this would be that the efficiency in capturing energy from those waves would probably be very low. $\endgroup$ – user4574 Oct 9 '20 at 2:20
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    $\begingroup$ @user4574 would having them form a film help if they coordinate to capture the energy? $\endgroup$ – Maciej Piechotka Oct 9 '20 at 4:20

Possible in theory, but not really in practice.

In theory, a bacterium could be engineered with some sort of acoustic piezo transducer - for example, a double cellular wall with vesicles and (say) a sodium or calcium "soup" inside. A sound wave of the appropriate frequency, which means in the very far ultrasound, would squeeze the soup from one end of the cell to the other, causing an electric potential to be created.

This in turn could be used to "recharge" ADP molecules into ATP, thereby making cellular respiration and oxygen supply unnecessary.

IMPORTANT: The bacterium would still need food to reproduce (nutrients supply both energy and "building materials"; sound waves would only supply energy). The bacterium would need to be large and have huge energy reserves to continue living when not exposed to ultrasound (it might have very basic oxidation capabilities, to be able to barely survive during silences. In that state, the bacterium would need oxygen again).

Transferring energy through ultrasound is nothing weird, we transfer kinetic energy to fluids and quartz dust via ultrasound to sterilize scalpels and the like.

The rub here is sound attenuation - ultrasound do travel through the human body and the air (we can get an ultrasound scan after all, and bats can echolocate mosquitoes), but not so well. To get an ultrasound scan you need the transducer to be pressed against the skin, with lubricating gel in the middle for good measure.

To drive enough energy to bacteria in the body, the sheer quantity of sound energy that would need to be pumped would be awesome, and harmonics would probably shatter everything in a considerable radius. Also, larger structures (such as the human body all around the bacteria) would almost certainly incur some kind of damage.

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    $\begingroup$ Well, you can't make an omelet without leveling some buildings. $\endgroup$ – The Square-Cube Law Oct 9 '20 at 14:28
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    $\begingroup$ If you expand the question to include any organism (of any size), it's possible to imagine creatures like those at the bottom of the Mariana Trench that barely use any energy by attaching themselves to the sea floor, and keep growing forever to capture more sound. Fun question! $\endgroup$ – hrishioa Oct 9 '20 at 19:14
  • $\begingroup$ @hrishioa Hm, that sounds interesting! I’ll edit it like that then. $\endgroup$ – DanPar Oct 9 '20 at 21:50

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