“What is octopus ink made of?”

Photo by: Sharon Ang

Cephalopods (we’re talking octopi, squid and cuttlefish) are famous for gushing ink.  The behavior known as “inking” is simply meant to create an underwater smokescreen of sorts for purposes of escape.  When an octopus feels that it’s time to bail on a hungry predator, it squeezes out a gout of ink, sometimes accompanied by mucus (ew), and makes a quick getaway, leaving its would-be eater befuddled by the ink cloud.

But what is that stuff clouding the water, and is it useful for anything other than dramatic effect?

What’s in that stuff?

The ink that cephalopods squirt is made mostly of melanin – the same stuff that creates your skin tone.  The color varies slightly between species; octopus ink is blackest, squid ink is black with a blue tinge, and cuttlefish squirt brown.  Sadly, fuchsia and chartreuse are not in vogue for underwater squirting.

Another chemical present in the ink is tyrosinase, an enzyme which controls melanin production.  Tyrosinase, as well as some amino acids found in the ink, is thought to act as an irritant to some predators, acting as a kind of underwater tear gas.  It’s possible that this compound confuses the signals sent to chemically sensitive predators, like eels.  It may also simply mess up the olfactory signals coming into a smell-happy creature like a shark.  Think of it as the approximate equivalent of blowing a handful of hot pepper powder into your stalker’s face.

The ink has also been found to contain dopamine and dopa, likely functioning to alert other cephalopods to danger (i.e. octo-speak for “AAAhhh!   SHARK!”)

The whole business of how inking affects predators has not actually been scientifically researched all that much outside of anecdotal evidence, nor has the full significance of the ink’s chemical makeup been fully determined.  If you’d like to delve further into what’s known, there’s a more in-depth study of marine mollusk inking published here.

Whatever exactly is going on with the special potion that is octopus ink, it has been working just fine for cephalopods for millions of years without the need for tweaking – even 130-million-year-old ink is chemically the same as today’s (but a lot more dried out, like those ballpoint pens in the junk drawer.)

But wait, there’s more!

Now along with the ink cloud, a cephalopod may also cry havoc and let slip the mucus of escape.  The mucus blobs stick in the ink and hold shape longer than ink alone, creating confusingly cephalopod-sized blobs to draw predators to the wrong bite target.  Upon release of its dark mucus-y decoys, the cephalopod will often change its color into a lighter camouflage mode as it darts away.

Evolution being handy as it is, some deep-sea varieties have developed an ink alternative for use in the dark depths where a shadowy ink cloud would make no difference: they release a glowing cloud of luminescent chemicals.  Totally cool.

This, as well as using ink pigment to help camouflage eggs and using camouflage to mimic their own mucus/ink blob are some of the related neat tricks in an ink-wielder’s arsenal.

Yeah but what can it do for me?

If you’re directly encountering cephalopods, say while diving, probably the main thing ink is going to do for you is annoy you.  But, up here on land, there are a couple uses for the stuff, both age-old and up-and-coming.

In ancient times, cephalopod ink was used as a dye (the brown known as “sepia” got its name from the Greek word for cuttlefish).  Nowadays, squid ink especially is used as a dye in cooking (P.S. it’s harvested right from the ink sac, so no mucus gets mixed in, yay).

Medical applications are also in the works.  Chemicals in the ink are toxic to some kinds of cells, including tumor cells and some germs, so perhaps there is a future in disease-fighting ink-based medicines.  As for the here and now, cuttlefish ink has been used to create the anodes on prototype edible batteries, which are anticipated to be useful for internal medical monitoring and drug delivery.

“Remember, Dear, to take your cuttlefish battery with your breakfast!”

What if I could have mutant octopus inking abilities?

Let us envision how the approximate anatomical layout and environmental effect of inking would play out with a human, because, why not?  In your new role as The Human Inkomatic, you would have an ink sac taking up space in your abdomen, with a release chute exiting at your nethers.  Your defense would cloud the vision and irritate the other senses of attackers while confusing them by creating a decoy while also alerting others of your species to the danger at hand.  Thus I would imagine you could blow out a large smoke screen containing an inflatable faux human alongside some tear gas with a sound like someone yelling “fire!”

That would be quite the mutant power.  Honestly, though, if I got to choose an octopus feature to be my mutant power, I would give inking a miss and rather go for the ability to fit through very small holes or, better yet, the octopus’ remarkable camouflage ability.  Or maybe take the cephalopod’s ability to communicate by color-changing its skin.  I wonder what my freckles would have to say?

OK, one more video link, because these creatures are just so cool!

“Do the people in Antarctica know they're upside-down?”

Photo by David Mark

 

My son asked this when he was five, with a great look of wonder and slight concern on his face.  One could say the answer is “no,” because they’re standing right-side-up relative to the earth beneath their feet, but I’m going to go with the globe-comparison approach.  My answer is: “yes,” insofar as they know that they are upside-down as they would appear if placed on a globe, being on the southern end of the earth, and that position being designated “down” on standard modern maps, 3-D and otherwise. 

I confidently say so because Antarctica appears to have no indigenous people and therefore everyone there has come from elsewhere on the globe, where I boldly presume they would have become aware that their travels would take them south, down, to the bottom of the earth as it appears on diagrams galore. 

Even if Antarctica did have natives, chances are they would probably have figured that Earth is round (based on the fact that people had figured out Earth’s shape at least as early as ancient Greek civilization) – but granted, they might not see themselves at the bottom.  I have seen no evidence for any native Antarcticans, however.

Do the people in Antarctica buy into the idea that they’re on a globe-shaped object?  There aren’t a whole lot of statistics available detailing how many people on earth believe it’s not spherical, but I can tell you that The Flat Earth Society membership represents less than   1/100,000^th of one percent of the world population, so the odds are good that everyone in Antarctica does, in fact, think they are on a round planet, the south pole of which we have generally agreed to place at the “bottom.”

Notice that the questioning child was not concerned with whether the folks at the bottom of it all would fall off.  He was also amenable to the idea that while the South Pole Station crew may know that, on a globe, they’re “upside-down,” they seem right-side-up to themselves, thanks to gravity and perspective.

Questions beget questions, and as this one could be either succinctly or elaborately answered, it also begs a few more items to be pondered.

Like, why is Antarctica even considered “upside-down?”   And what is actually on the bottommost point on the globe when it’s mounted with its tilt?  And have any civilizations ever thought they were upside-down on the earth?  Or about to fall off?

Why is North “up?”

The placement of north on the topside of a map is generally attributed to Claudius Ptolemy, a Greek scholar living 90-168 AD.  Exactly why he did this is unknown (perhaps his notes on the matter were in the Library of Alexandria before it burned) but the practice was heartily adopted by European Renaissance mapmakers, for whom ancient Greek pedagogy was all the rage. 

It’s been theorized that the preference was to put the better known and/or more important places at the top, and for a Greco-European mapmaker, that would be Europe.   (So if you put the important things at the top of the map, what would you have there?  I’m thinking I might top mine off with the local coffee shop.)

Still, maps worldwide were not standardized to be north-up until well after that Renaissance fad.  Early European maps often had east up, while Egyptian, Arab and Chinese maps often faced south, and American maps sometimes pointed westward.  Every mapmaker had their reasons for compass placement, but these reasons were largely lost to time, including the original reason for north-up…but that’s the standard that prevailed.

Still, it’s neat to see how the world looks on north-down maps for a change.

What’s bottom-most on a tilted globe?

Globes are usually mounted at a 23.5° tilt in keeping with the relative position of Earth to the Sun.  When you look at the bottom of the globe in this case, since the South Pole is tilted to the side, the actual “bottom” of the earth falls along the Antarctic Circle, with the seas and land masses along that line rotating their way into and out of the bottom spot.  The honor of the bottommost spot goes to the edges of Antarctica, mostly coastline and islands,  including the South Shetland and South Orkney Islands which get a close shot at being at the bottom.  Those folks probably know they’re upside-down, globe-wise, as well.

Has any human culture thought they were walking on the earth upside-down?  Or that they could fall off?

Thus far in my travels, I have found no hint of any culture that has thought people would drop off the earth because they are upside-down on it.

There have been times and places when the prevailing vision was of a flat earth.  Most ancient flat earth models I’ve encountered envisioned the world as a disk of land floating in water, so in that case, if you fell off the end of the earth, you would get wet.  Perhaps if you took a rowboat beyond the land’s edge, you may find the water drops off, too, although I haven’t yet come across historical documentation of whether these cultures envisioned an end to the water as well.  Although the idea of a world-end waterfall sure makes for a great story. 

The final word

But enough of my postulating.  Let’s go to the source and ask someone who has been at South Pole Station if she knew she was upside-down at the time.

Speaking to her own perspective on the experience, widely-traveled author Heather Shumaker says, “No, I didn't notice being upside down, but I did notice being high up.  The South Pole was on top of 2 miles of ice, so it was like being on top of a very high mountain.”

Turns out that being at the “bottom” of the earth can actually give one the sense of being on top of things!

As far as the ultimate description of placement, Shumaker sums it up perfectly: “We're all upside down to somebody.  It just depends on the way you look at the planet.”

"Which is hotter -- lava or re-entry from space?"

Photo from WikiImages

Leave it to a seven-year-old to pose such a dramatic question as this!  Lava and re-entry both make things red-hot, right?  So are they comparable?

 
Lava -- which, to review, is what we call magma when it’s on Earth’s surface -- has varying temperatures depending on what kind of rock has melted to create it.  The hottest lava is made of basalt and flows in the range of 1850-2200°F.

The heat created by an object falling through our atmosphere is a bit more than the glowing warmth of lava.  The Orion spacecraft comes down facing temperatures up to 4000°F, and meteors, with their varying shapes and trajectories and lack of heat shields, often get to burn up at even hotter temperatures.  But, to give lava a fair shake at impressiveness-of-hotness, let’s take the space shuttle as our comparative re-entry representative.  The space shuttle’s surfaces reached temperatures in the 2700-2900°F range.

So, re-entry is hotter than lava, but a really hot volcano at 2200°F is not so far off from a slow space shuttle blazing in at 2700°F that it couldn’t at least compete in a metal-melting contest.

Both lava and re-entry are hot enough to melt all of the “softer” metals, meeting a division of ability right around iron.  Cast iron melts in the 2060-2200°F range, so whether you cast your frying pan into the fires or Etna or out the shuttle window, you can kiss it goodbye. 

Your wrought iron furniture, however, melts at 2700-2900°F, so while it would be OK in a volcano, it would most likely melt away in the atmosphere with so many other shooting stars.  So in the metal melt-off, we do have to hand it to re-entry as the heat master, because if you just dropped a wrought-iron gate from on high, it would be toast. 

However, if that iron gate was balled up into a wrought iron wad, it just might actually stand a chance of surviving a tumble through the atmosphere.  In regular gate form, it would need some propulsion assistance and/or heat shields and/or a nice capsule covering to keep it intact and it would probably still be red-hot and perhaps a bit wobbly, but if it was wadded into a blunt shape and could create a good shockwave, at space shuttle speeds, it could survive. 

 

You know what else is made of wrought iron?  The Eiffel Tower.  That just begs for some visualization, doesn’t it?

So, we have determined that a lava flow would not liquefy the Eiffel Tower, but a straight fall from space would.  Now let’s picture making some special modifications ourselves to help the Tower conquer re-entry.  The problem for the Eiffel Tower in reality is that, while the heat levels of re-entry built up in the space shuttle’s descent would not be enough to melt it, its shape would not create the kind of heat-protective shockwave that blunt-shaped re-entry vehicles use to survive falling through the atmosphere.  You would end up with a bunch of giant molten strips of slag falling at you.  But say you equipped the Tower with shuttle-like descent capabilities – add a big domed heat-shielded side to hide above and some thrusters to maintain alignment for proper descent speed – then, were the Eiffel Tower, for some good and plausible reason, to come careening down from space, it might survive the heat of the fall.  The sudden stop at the end would be a problem, though.  Now picture a glowing-hot Eiffel Tower deploying its gigantic parachute…where do you think it should land?

 
Now on to the next thing to ponder on the topics of lava and re-entry… what if you needed to re-enter from space onto a planet that was already hotter than lava?  Hmmm…