Jellyfish Swimming Is Mixing the Oceans 47
eviltangerine writes "A new article from LiveScience suggests that marine creatures, such as the jellyfish, may contribute as much to ocean mixing as wind and tides. Wired is also covering the story and includes a video of the jellyfish in action. From the article, 'The mere act of swimming implies that some water travels with the swimmer,' said CalTech engineer Kakani Katija, co-author of the study in Nature Wednesday. 'Drift applies to all animals, to anything with a body.' No word yet on when the jellyfish blender is to debut."
Re: (Score:1, Informative)
The Institute's Media Relations Department specifically requests that all press organizations should use either use "Caltech" or "California Institute of Technology," and that "CalTech" or "Cal Tech" is nonstandard. It isn't about proper use of English, it's just that it makes sense to use a single standardized abbreviation.
Incidentally, as an alumnus, I've noticed that several street signs located in the Pasadena area that point to Caltech are similarly incorrect. Not that I really care. That place took
This problem must be addressed! (Score:1)
Jelly-o-matic (Score:1, Funny)
"Drift applies to all animals, to anything with a body.' No word yet on when the jellyfish blender is to debut."
Having been stung by a jellyfish the image of one in a blender did bring a smile to my face. They might make a nice sushi smoothie.
Re:Jelly-o-matic (Score:4, Funny)
Having been stung by a jellyfish the image of one in a blender did bring a smile to my face. They might make a nice sushi smoothie.
Or use them to make a stinger [wikipedia.org] to remember.
Huh? (Score:2)
" 'The mere act of swimming implies that some water travels with the swimmer," said CalTech engineer Kakani Katija"
Temporary vortices aside, I think that Sir Isaac Newton might take issue with this statement.
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Agreed, End of discussion.
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You don't want to join a discussion on membrane flappage and its effect on the aqueous continuum? Well, I guess that's up to you...
;-D
Re:Huh? (Score:5, Informative)
At the very least, the organism contains water.
However, Sir Newton shouldn't have any problem with the statement. Obviously, some water must be pushed away from the swimmer, but so long as the total water pushed backward equals the sum of the mass of the swimmer plus the sum of the water carried with the swimmer.
Furthermore, once the Jellyfish is in motion, any water carried with it, like the Jellyfish, will want to continue in motion. The most low-energy state allows the water already in motion with the Jellyfish to continue moving, while water in front of the animal is pushed aside and around back.
Convoys (Score:1, Insightful)
Exactly. I mean isn't that why ships and trucks travel in convoys?
Re:Convoys (Score:5, Funny)
Ships in convoys are too far apart to affect each other much, unlike a crowded sail ship race.
Ships travel in convoys due to the motion of torpedo particles.
Re:Huh? (Score:5, Insightful)
Unless the swimmer is frictionless, their sides drag some water along with them. Yes, water must be displaced backwards, but it's not false that "some water travels with the swimmer".
Re:Huh? (Score:5, Insightful)
Not a physicist but a physician. This makes sense - since it's roughly same way blood moves in blood vessels. Flow along the wall of the blood vessel is minimal. The greatest flow is in the center of the vessel, with diminishing flow the closer you get to the wall. That's why flow increases dramatically in larger blood vessels (it's a function of the fourth power of the radius - called the LaPoiseuille equation [wikipedia.org]).
Again I'm no physicist, but I assume that if you have something pushing a fluid through a medium, you could define two boundaries that are not movable - the solid thing doing the pushing, and looking further and further out eventually you reach a "column" of water where the force does not get transmitted and is thus also static. Although it would be hard to get laminar flow in this scenario, it's not hard to imagine the greatest flow being generated where the greatest pressure change is - ie somewhere in the middle of the area described. The pressure change (and thus the flow) will be minimal where the static "walls" are, be they "real" (as in a solid fin, or an arm) or "not real" as in a non moving column of water.
Re:Huh? (Score:4, Informative)
Of course, a bunch gets flung back as well, which is what I assume you meant.
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I think what you are referring to as currents is the displacement of the liquid and the weight of the surrounding liquid pushing it back.
However, the concept of water or liquid moving little around the object compared to more movement further away is a matter of friction and displacement. It gets a little more complicated to explain when you deal with buoyancy and displacement as other factors such as surface tension and gravity become involved but it's mainly a matter of friction. If you are neutrally buoy
Re:Huh? (Score:5, Funny)
Well yes if you put the vorticies (turbulance) to one side you have probaly eleminated the mode of travel for the water. Customary car analogy: If I take the wheels of my car it will no longer roll down hill.
not too surprising (Score:5, Interesting)
The topic of ocean mixing is a huge subject [amazon.com], and seems to implicate just about everything you can think of: the atmosphere, geologic activity, emergent effects from complex system dynamics, boundary layers, energy dissipation, fluid turbulence, climate change, dissolved minerals, the rotation of the earth, gravitational effects of the moon, etc., etc. It's not particularly surprising to me that the actions of marine life are a significant component as well, though it's interesting to see actual numbers claiming to demonstrate it.
Re:not too surprising, but fascinating (Score:4, Insightful)
I recently read history of herring runs spawning in the Salish Sea [wwu.edu] so abundantly that the water was white, and that eggs were laid on everything in the water, such that they could be collected simply by submerging cedar branches. Not to mention historical quantities of fish all over the world...
Just heard a flying astronaut again describing how thin a veil the atmosphere is and I realized that for how big a volume the earth is, its livable surface area(biosphere) isn't really that large at all. *duh* but I never connected spherical geometry (area vs volume) and the concept of how profoundly we could affect our environment when the earth is soo big.
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"...and seems to implicate just about everything you can think of: the atmosphere, geologic activity, emergent effects from complex system dynamics, boundary layers, energy dissipation, fluid turbulence, climate change, dissolved minerals, the rotation of the earth, gravitational effects of the moon, etc., etc..."
You forgot Sea Cow farts.
http://en.wikipedia.org/wiki/Sea_Cow [wikipedia.org]
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Durnit.
Forgot specifics.
Note 5 on the Wiki page. Regarding Hydrostasis.
A neglected factor (Score:2, Insightful)
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maybe they will discover that moving boats do it too?! Or birds do the same with the air?!
Boats don't mix water very much vertically, at least not much below the surface layers, anyway. It's the vertical mixing, of both salinity and temperature, that makes a difference in thermohaline flow.
My guess, and I suppose I could be wrong here, is that the contribution of birds to atmospheric mixing is below the noise level. The atmosphere is strongly heated from the bottom, which results in thermal instability ("thermals"). The oceans, on the other hand, are primarily heated from the top (except ar
Best Day Ever? (Score:1, Funny)
Let's All Go Jellyfishing!!! (This is the Best Day Ever!!!)
I don't mean to language-freak out here, but... (Score:5, Insightful)
I mean, I know headlines can't convey everything, but it seems a few leaps have been made...
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gosh, isn't energy measured in Joules anymore?
You probably already know this, but a Watt is a Joule per second. It's like the difference between distance and speed.
It's Caltech not CalTech (Score:1)
Like Slashdot not SlashDot... now that wasn't hard was it?
Martini (Score:1)
Pulsated, not stirred!
NPR has a solid commentary and some nice video (Score:4, Informative)
which is definitely worth checking out. [npr.org] Really amazing stuff!
The BBC [bbc.co.uk] story also has some interesting points about why jellyfish in particular are being looked at.
i dont believe it (Score:1)
That's like saying the movement of animals affect the wind. Let me guess, birds were once so populous that the beating of their wings....what bullshit. Sounds kewl tho...you know, the kind of cool that's so stupid it's interesting?