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"Argonaut" Octopus Sucks Air Into Shell As Ballast
audiovideodisco writes "Even among octopuses, the Argonaut must be one of the coolest. It gets its nickname — 'paper nautilus' — from the fragile shell the female assembles around herself after mating with the tiny male (whose tentacle/penis breaks off and remains in the female). For millennia, people have wondered what the shell was for; Aristotle thought the octopus used it as a boat and its tentacles as oars and sails. Now scientists who managed to study Argonauts in the wild confirm a different hypothesis: that the octopus sucks air into its shell and uses it for ballast as it weaves its way through the ocean like a tiny submarine. The researchers' beautiful video and photographs show just how the Argonaut pulls off this trick. The regular (non-paper) nautilus also uses its shell for ballast, but the distant relationship between it and all octopuses suggests this is a case of convergent evolution."
And for it's next trick, the octopus will change its color!
Oh wait, some already do that.
"There is a way that seems right to a man, but its end is the way of death." Proverbs 16:25 (NKJV)
And here I thought in submarine movies the term, "blow the ballast tubes" indicated releasing sea water that is held inside the tubes to allow for bouyancy. Hence, allowing for a sharp decrease in depth. So yes, while "ballast" does indicate a weight keeping a ship or object submerged, it can also be used as a "ballast tube" that causes lift.
It grows back: "Males generally form a new hectocotylus in each new season."
In Liberty, Rene
Yes, a buoyancy control device (BCD) - usually an inflatable vest connected to your air cylinder - is standard diving equipment.
Scuba divers will know that to stay neutrally buoyant, as you dive deeper, you must add extra air to your buoyancy control vest, and vent air when rising.
Being neutrally buoyant is an unstable equilibrium, so if you are changing depth and do nothing or if you get your correction wrong, you end up rising/sinking even faster.
If you do maintain your buoyancy well, your energy usage (for example for divers, as measured by your air usage) is hugely reduced - it makes sense to get it right if you plan to spend significant time at a roughly constant depth.
The only difference in this case, is that the argonaut has no easy push-button to change buoyancy mid-dive, and instead has to return to the surface every time.
I'd tell a UDP joke, but you may not get it. I'd tell a TCP joke, but I'd have to keep repeating it until you got it.
When you "blow the tubes" you're using compressed air to force the water out. The water is the ballast.
-jcr
The only title of honor that a tyrant can grant is "Enemy of the State."