n Harry Potter and the Goblet of Fire, we're introduced to mermaids who've apparently been living in secret at the bottom of a Scottish loch for thousands of years. This is all well and good when you've got magic on your side, but NBC's new Monday night show Surface offers merfolk of a more sinister nature. Large enough to eat small boats in a single gulp, these creatures—apparently intelligent, certainly dangerous—live in the magma of the Earth's interior and burrow up through the sea floor, creating undersea volcanoes that contribute to rapid global warming. And without magical powers, they have only science to preserve them.
Can we believe in these monsters? Well, in the first place, they look a lot like the mythical salamander, a creature that could supposedly live in fires and furnaces. According to Aristotle and Pliny, among others, this lizard had either a wooly asbestos skin or else a milky, flame-retardant secretion that protected it against heat. No such creatures are known in the modern world, but then again, a lot of species have gone extinct since the time of the ancient Greeks.
In the second place, two-thirds of the Earth is covered by ocean, so it's quite sensible to think that unknown creatures—even large ones—may still be lurking down there. After all, our first live glimpse of the giant squid Archeteuthis—the "kraken" of ancient sailors' myths—was only seen two months ago, and in the deepest reaches of the ocean, it seems every submersible mission uncovers some new species or other. Nothing implausible about that!
Life as a boiled egg
But what about living in red-hot magma? As the show itself is quick to point out, Earth already has thriving ecosystems around its undersea volcanic vents, including single-celled organisms called thermophiles—bacteria that survive above the sea-level boiling point of water. The temperature limit for protein-based life seems to be around 160 degrees centigrade. Above this temperature, the proteins gloop together like a boiled egg.
Which is a problem, because first of all, these temperatures are only survivable by single-celled organisms, and second of all, these superheated bacteria are "obligate thermophiles" and "obligate barophiles," specially designed for their hot, crushing environment, and will die at room temperature or sea-level pressure. By contrast, when they leave their magma chambers, the creatures of Surface can slither around dry at sea level and can easily withstand the pressure and near-freezing temperatures of the world's deepest oceans. That's quite a range!
Still, think of a glass cooking pot. If you fill it with cold water and slap it on the stove, you could have a long wait before the water actually boils. Now, asbestos (a fibrous, naturally occurring mineral notable for being fireproof and for causing lung cancer) insulates six times better than ordinary glass, while air insulates more than 100 times better. A compromise between the two, "rock wool" or silica fiber insulates about 20 times better. This light, strong material can be fashioned into blocks, tiles or flexible blankets, and in the heat shield tiles of the space shuttle it can withstand repeated exposures of up to 1650° C (3000° F). Silica aerogel would be even better—you could get the same insulation as rock wool with one-third the thickness!
Eating the alien
Could we expect to find such materials in a living creature? Sure, animals incorporate minerals into their bodies all the time. Sea shells use aragonite, calcite and calcium carbonate from seawater, while the hard enamel coating of human teeth is made of apatites rich in calcium, phosphate and fluoride from the small amounts of sand and grit in our food. It's no great stretch to believe an animal could grow scales made of something similar to rock wool, which could easily withstand lava temperatures of 700° to 1,200° C (1,300° to 2,200° F), protecting the soft flesh behind them for brief periods of time.
But what about prolonged exposure? Nothing can block the flow of heat; even the best insulation just slows it down. If a salamander wants to sit in the lava all day, that searing heat will definitely find its way inside. Ergo, we need a way to cool down the creature's interior. Since these animals are aquatic anyway, the handiest mechanism would be to store water in a sac and bleed it away as water vapor. To sweat, in other words. Unfortunately, for every joule of heat that leaks through their rock wool scales, the creatures would need to evaporate about half a milliliter of water.
So, for example, if the total heat absorption is equal to what a space shuttle experiences during re-entry, there'd need to be about 25,000 liters (or 25 cubic meters) of sweat per second. Failing that, the creature's internal temperature would rise by about nine and a half degrees per second. So, even if they're as heat-resistant as the hardiest thermophilic bacteria, and even if they start out at a chilly sea-floor temperature of around 1°C, the critters can stand only about 17 seconds in the magma before their fever reaches the lethal 160-degree mark.
Since remote camera images clearly show them basking at the bottoms of volcanoes for much longer than that, we have to assume they represent some entirely new biology, unknown to modern science. Still, there don't seem to be any spaceships, and the creatures don't look particularly alien and seem in fact to be distant relatives of the extinct plesiosaur and the modern electric eel. God knows they have a taste for goldfish, powerboats and people, implying they're made of the same basic stuff as other earthly life. So the obvious solution, it seems to me, is for humans to turn the tables on our unwelcome guests and start harvesting them as food. Given their fantastic regenerative powers, we'd have to eat quickly to stay ahead, so we're talking about a meal to rival even the grandest Thanksgiving feast. But to (burp) save the world, we've all got to do our share. Besides, if the laws of physics are any guide, the creatures should come to us pre-cooked!
Sources:
(I couldn't find the total heat absorption of the space shuttle anywhere, but according to The Space Shuttle Operator's Manual, during reentry the internal structure of a shuttle orbiter rises from around 20°C to 175°C. Assuming the 75,000-kg structure is made of equal parts aluminum (with a specific heat of 900 J/kg°C), graphite (720 J/kg°C) and glass (8400 J/kg°C), a 155°C temperature rise means it absorbs 38 billion Joules. Over the course of a 13-minute blackout period, this equates to a power absorption of 50 megawatts. The rest of the calculation assumes the creature's internal structure weighs the same as a space shuttle but consists mostly of water.)
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Lide, David R., ed.: CRC Handbook of Chemistry and Physics, CRC Press, 2004 edition
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The Encyclopedia Britannica, 2004 Edition: ("enamel", "lava")
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Kerry Mark Joels and Gregory P. Kennedy: The Space Shuttle Operator's Manual, Bantam Books, 1982
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McCarthy, Wil: Hacking Matter, Basic Books, 2003
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Wil McCarthy is a rocket guidance engineer, robot designer, nanotechnologist, science-fiction author and occasional aquanaut. He has contributed to three interplanetary spacecraft, five communication and weather satellites, a line of landmine-clearing robots and some other "really cool stuff" he can't tell us about. His short writings have graced the pages of Analog, Asimov's, Wired, Nature and other major publications, and his book-length works include the New York Times notable Bloom, Amazon "Best of Y2K" The Collapsium and most recently, To Crush the Moonn. His acclaimed nonfiction book, Hacking Matter, is now available in paperback.
