The mysteries of the deep

I've heard it said that we know more about the surface of the Moon than we do about the deep oceans on the Earth.

I've never seriously attempted to find out how accurate this is (and honestly, don't know how you'd compare the two), but I suspect it's substantially correct.  About seventy percent of the Earth's surface is covered by water, and given the difficulty of seeing what's down there -- even by remote telemetry -- it's no wonder we're still finding things in the ocean we never knew existed.

Take, for example, the study that appeared in Current Biology last week about the Clarion-Clipperton Zone.  The CCZ is the region between the Clarion Fracture Zone and the Clipperton Fracture Zone in the central Pacific, with an area of about six million square kilometers.  It contains several (apparently dormant or extinct) volcanoes, a number of submarine troughs of uncertain seismic activity, and a rough, mountainous topography.

[Image is in the Public Domain courtesy of the United States Geological Survey and the Department of the Interior]

The prevailing wisdom has been that most of the open ocean has relatively low biodiversity.  To put it more simply, that there just ain't much out there.  If you're in the middle of the ocean, any given cubic meter of water is unlikely to have many living things in it beyond single-celled plankton.  And -- supposedly -- the floor of the deep ocean, with crushing pressures, no light, and constant temperatures just above the freezing point of water, is often pictured as being pretty much devoid of life except for the bizarre hydrothermal vent communities.

That concept of the deep oceans needs some serious re-evaluation.  Last week's paper featured a survey of the abyssal life in the Clarion-Clipperton Zone, and found nearly six thousand species of animals...

...of which 92% were unknown to science.

The coolness factor of this research is tempered a little by the reason it was conducted.  The CCZ is being studied because of its potential for deep-sea mining.  The seafloor there has a rich concentration of manganese nodules, concretions of metal oxides and hydroxides (predominantly manganese and iron, with lower concentrations of other heavy metals), which are of immense value to industry.  Add to that the fact that the CCZ is in international waters -- so, basically, there for whoever gets there first -- and you have a situation that is ripe for exploitation.

What makes this even more complex is that the metals in the nodules are used, amongst other things, for high-efficiency electronics, including renewable energy systems.  The cost, though, might be the destruction of an ecosystem that we've only begun to study.

"There are some just remarkable species down there," said Muriel Rabone, of the Natural History Museum of London, who co-authored the study.  "Some of the sponges look like classic bath sponges, and some look like vases.  They’re just beautiful.  One of my favorites is the glass sponges. They have these little spines, and under the microscope, they look like tiny chandeliers or little sculptures.  There are so many wonderful species in the CCZ, and with the possibility of mining looming, it’s doubly important that we know more about these really understudied habitats."

So much of what humans have done seems to be blundering around blindly and only afterward seeing what the consequences are.  Perhaps we should investigate the ocean's mysteries before we attempt to use it for profit.

It seems fitting to end with a quote from H. P. Lovecraft, whose fascination with the ocean returns time and time again in his fiction: "But more wonderful than the lore of old men and the lore of books is the secret lore of ocean.  Blue, green, grey, white, or black; smooth, ruffled, or mountainous; that ocean is not silent.  All my days have I watched it and listened to it, and I know it well.  At first it told to me only the plain little tales of calm beaches and near ports, but with the years it grew more friendly and spoke of other things; of things more strange and more distant in space and in time.  Sometimes at twilight the grey vapours of the horizon have parted to grant me glimpses of the ways beyond; and sometimes at night the deep waters of the sea have grown clear and phosphorescent, to grant me glimpses of the ways beneath.  And these glimpses have been as often of the ways that were and the ways that might be, as of the ways that are; for ocean is more ancient than the mountains, and freighted with the memories and the dreams of Time."

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Reconsidering Storegga

Ever heard of the Storegga Slide?

It sounds like some bizarre crossover between Scandinavian folk music and a country line dance, but it isn't.  It's an event that took place 8,150 years ago (plus or minus thirty years or so) and is entirely unlike anything we've seen since.

The simplest description is that it was an underwater landslide.  But this thing was bigger than any landslide you've ever heard of.  It took place in the North Atlantic between Iceland and Norway.  For uncertain reasons -- but probably linked to seismic activity along the Mid-Atlantic Ridge -- a 290-kilometer-long piece of continental shelf collapsed, sending an estimated 3,500 cubic kilometers of debris sliding down the continental slope, where it ultimately piled up on the floor of the deep ocean.

What happened next is kind of mind-blowing, but to get how it worked, we have to take a brief digression into biochemistry.

It's thought that the most numerous organisms on Earth are methanogens, a group of bacteria that are kind of everywhere in anaerobic mud (including the sediments of the oceanic abyss).  As you might guess from the name, these bacteria produce methane as a waste product of their metabolism.  If they're living at the bottom of a shallow lake, the methane is in gaseous form and bubbles up when the mud is disturbed, giving it the name "marsh gas." 

But something more interesting happens in the deep ocean.  At the enormous pressures and low temperatures found in the abyss, the methane forms a weird substance called methane clathrate (also known as frozen methane hydrate).  It's a crystalline slush made of a latticework of water and methane.  If you bring it up to the surface -- which, as you'll see, has to be done carefully -- it looks like snow.

But it's flammable.

[Image of methane clathrate is in the Public Domain, courtesy of the United States Geological Service]

So back to the Storegga Slide, wherein an enormous clump of debris went tumbling down the continental slope... and landed in the clathrate-rich mud of the abyssal plain.

Methane clathrate isn't just flammable; it's unstable.  If anything wallops it hard enough, it breaks up the lattice, and the two compounds separate.  The methane turns back into a gas, the water to a liquid. 

Some of you probably have gone scuba diving, and noticed what happens to the air bubbles when you breathe out.  The bubbles rise (duh) but more interestingly, they expand.  The higher you go in the water column, the lower the pressure, and the more the air in the bubble is free to balloon outward.

A lot.  One liter of methane clathrate produces 169 liters of methane gas (at zero degrees Celsius and one atmosphere of pressure).  So when the Storegga Slide crashed into the methane clathrate on the ocean floor, it caused an unknown (but huge) quantity of methane clathrate to fall apart, making it suddenly increase in volume by a factor of 169 -- triggering an explosion that displaced enough water to generate a megatsunami.

This comes up because of a paper last week in the journal Boreas that looked at the effect of the Storegga Slide on nearby land, and found that the tsunami this generated was on the order of thirty meters high.  For comparison purposes, the devastating tsunami generated by the 2011 Japanese earthquake maxed out at a little under ten meters.

The Storegga Slide tsunami was three times higher than that.  It completely inundated what is now northern Scotland.  It's also likely this is what destroyed Doggerland, a broad, marshy land that once connected Great Britain to northern continental Europe.  Doggerland was already in trouble -- at this point, the climate was warming and the seas were rising -- but the Storegga Slide tsunami would have been catastrophic.  Unlike the rugged terrain of Scotland, Doggerland was a featureless flat plain, and the tsunami rolled across it like a bulldozer.  This severed Great Britain from the rest of Europe -- isolating the Mesolithic people there permanently.

[Image licensed under the Creative Commons Francis Lima, Doggerland3er en, CC BY-SA 4.0]

All this isn't speculation, by the way.  The fact that Doggerland was once dry land (well, dry-ish) was established when a trawler out in the North Sea east of the Wash brought up a barbed antler point that was dated to about ten thousand years ago.  Since that time, lots of other artifacts have been discovered out there on the ocean floor, including prehistoric tools and the bones of mammoths, lions, and other extinct fauna.

And of course, what this makes me think about is how much more methane clathrate there is out there.  "Methane burps" like this one -- although the word "burp" kind of underplays how enormous these are -- release enough methane into the atmosphere to raise the temperature significantly.  In fact, a massive methane clathrate release is thought to be the cause of the Paleocene-Eocene Thermal Maximum of 55 million years ago, during which the average temperature climbed by between five and eight degrees Celsius, causing widespread extinction and ecosystem disruption.  That "methane burp" at the PETM is thought to have been a hundred times bigger than the Storegga Event.

Ready for the punchline?  The estimates are that the rate we're pumping carbon into the atmosphere from fossil fuel burning is right around the same as the rate that led to the PETM.

So by all means, governmental leaders, continue to ignore the scientists who have been warning you about this for decades.  Business as usual, damn the torpedoes, full speed ahead.

The universe is a dangerous place.  The Storegga Slide and the resultant tsunami happened suddenly and without warning.  Much more commonly, earthquakes and volcanoes can cause tremendous loss of life and property.

But it's a little terrifying to see that what we're doing to our home right now is equivalent to some of the most violent ecological shifts in the geologic record.

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I'm in awe of people who are true masters of their craft.  My son is a professional glassblower, making precision scientific equipment, and watching him do what he does has always seemed to me to be a little like watching a magic show.  On a (much) lower level of skill, I'm an amateur potter, and have a great time exploring different kinds of clays, pigments, stains, and glazes used in making functional pottery.

What amazes me, though, is that crafts like these aren't new.  Glassblowing, pottery-making, blacksmithing, and other such endeavors date back to long before we knew anything about the underlying chemistry and physics; the techniques were developed by a long history of trial and error.

This is the subject of Anna Ploszajski's new book Handmade: A Scientist's Search for Meaning Through Making, in which she visits some of the finest craftspeople in the world -- and looks at what each is doing through the lenses of history and science.  It's a fascinating inquiry into the drive to create, and how we've learned to manipulate the materials around us into tools, technology, and fine art.

[Note: if you purchase this book using the image/link below, part of the proceeds goes to support Skeptophilia!]

Black as the night

You wouldn't think that fish living three miles deep in the ocean, far beneath the level that sunlight can penetrate, would worry much about being seen.

Well, I'm not sure they're worried, exactly.  But they still have the problem that if they do somehow get seen, they're likely to get eaten.

This lies at the heart of the reason that bioluminescence exists in the deep ocean.  You probably know that bioluminescence is the ability of some organisms to use chemical reactions in their bodies to emit light.  (Fireflies are a common example.)  In the deep ocean, it was thought the main reason animals might do this is to create a lure; the illuminated "fishing pole" of the grotesque angler fish brings in curious smaller fish, which then get turned into lunch.

[Image licensed under the Creative Commons Masaki Miya et al., Bufoceratias, CC BY 2.0]

There are other functions for light-emitting structures besides lures.  Squid that live in shallow water have ink they squirt into the water then they're attacked, creating a dark cloud to confuse the predator, thus allowing the squid to escape.  But if you live at a depth where its perpetually dark, black ink is fairly useless; so there are deep-sea squid that emit luminescent ink, creating a burst of light to startle the predator and give the would-be dinner a chance to live for another day.

Last week in Current Biology, though, there was a paper wherein I learned about another reason for bioluminescence in the deep ocean.  In "Ultra-black Camouflage in Deep-Sea Fishes," by Alexander L. Davis, Sönke Johnsen, and Karen J. Osborn (Duke University), Kate N. Thomas (The London Museum of Natural History), Freya E. Goetz (Smithsonian National Museum of Natural History), and Bruce H. Robison (Monterey Bay Aquarium Research Institute), we read about fish like the evocatively-named fangtooth, Pacific blackdragon, and black swallower, whose skin is amongst the blackest naturally-occurring substances, reflecting less than 0.5% of the light the falls on it.

But as with the squid ink, why bother to evolve such dark skin if there's no light there to reflect?  The answer turns out to be that there is light there to reflect; the bioluminescence emitted by other predatory fish.  If you're in the complete darkness, even the reflection of a tiny amount of light from your body might give away your position.  So this is a third reason for deep-sea bioluminescence; not as a lure, nor a distraction, but as a searchlight.

These fish, however, are so dark that even in bright sunlight they look like black silhouettes, as study co-author Karen Osborn found out when she tried to photograph them.  This confers a significant advantage over other fish, even if there's only a marginal difference in the skin blackness.  The authors write:

At low light levels, as is the case with a fish reflecting <2% of an already dim source (i.e., a bioluminescent flash, lure, glow, or searchlight), against the black deep-sea background, the model predicts that the sighting distance is proportional to the square root of the number of photons being reflected back to the viewer.  Using this relationship, we find that reducing skin reflectance from 2% to 1% reduces sighting distance by 29% and that decreasing further to 0.5% or 0.05% reflectance reduces sighting distance by 50% and 84%, respectively.  Because visual predators typically search a volume of space, and this reduction in sighting distance is linear, the camouflage benefits of ultra-black skin may be even greater than the reduction in sighting distance calculated here.  Given the small size of the fishes studied here, it is likely that predator-prey interactions occur over short distances, where even small differences in sighting distance can have meaningful effects on interaction outcomes.

I've read that we know less about the abyssal regions of the ocean than we do about the surface of the Moon.  I don't know if that's true -- it's a little hard to quantify what we don't know about something -- but what's certain is that the deep ocean harbors some astonishingly weird creatures.  I'll end with a quote from H. P. Lovecraft, in whose writings the ocean represents everything that is dark and mysterious about the universe: "But more wonderful than the lore of old men and the lore of books is the secret lore of ocean...  The process of delving into the black abyss is to me the keenest form of fascination."

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This week's Skeptophilia book recommendation of the week is about as cutting-edge as you can get, and is as scary as it is fascinating.  A Crack in Creation: Gene Editing and the Unthinkable Power to Control Evolution, by Jennifer Doudna and Samuel Sternberg, is a crash course in the new genetic technology called CRISPR-Cas9 -- the gene-editing protocol that Doudna herself discovered.  This technique allows increasingly precise cut-and-paste of DNA, offering promise in not just treating, but curing, deadly genetic diseases like cystic fibrosis and Huntington's disease.

But as with most new discoveries, it is not without its ethical impact.  The cautious are already warning us about "playing God," manipulating our genes not to eliminate disease, but to enhance intelligence or strength, to change personal appearance -- or personality.

A Crack in Creation is an unflinching look at the new science of gene editing, and tries to tease out the how much of what we're hearing is unwarranted fear-talk, and how much represents a genuine ethical minefield.  Doudna and Sternberg give the reader a clear understanding of what CRISPR-Cas9 is likely to be able to do, and what it won't, and maps out a direction for the discussion to take based on actual science -- neither panic and alarmism, nor a Panglossian optimism that everything will sort itself out.  It's a wonderful introduction to a topic that is sure to be much in the news over the next few years.

[Note: if you purchase this book using the image/link below, part of the proceeds goes to support Skeptophilia!]

Oarfish, earthquakes, and shadow people

I'm perpetually astonished at how little it takes to get the woo-woos going.

I suppose, though, that's the definition of confirmation bias -- taking thin evidence (or skimpy anecdote) as incontrovertible support for what you already believed.  Me, I try to approach stuff with more caution -- I'm not perfect, but I do my best when confronted with a strange or intriguing story to stop and think, "Wait a moment, how do I know this is true... and means what people are saying it means?"

I ran into two particularly good examples of that yesterday.  In the first, we have people saying that the appearance of three dead oarfish in coastal Japan is indicative that they're in for a major undersea earthquake and tsunami.  Now, there's no doubt that seeing an oarfish would make you sit up and take notice; they live in deep waters and are usually only seen when they're dead or dying, and can get up to eleven meters long.  (Yes, I double-checked that statistic, and it's correct.)

American servicemen displaying a dead oarfish they found off the coast of California in 1996 [Image is in the Public Domain]

So I suppose it's no wonder that people stop and say, "Okay, that's weird," when they see one.  But oarfish are not uncommon, despite seldom being seen; and there are lots of cases of dead oarfish washing up on shore that were not followed by geological catastrophes.   "I have around twenty specimens of this fish in my collection so it’s not a very rare species, but I believe these fish tend to rise to the surface when their physical condition is poor, rising on water currents, which is why they are so often dead when they are found," said Hiroyuki Motomura, professor of ichthyology at Kagoshima University.  "The link to reports of seismic activity goes back many, many years, but there is no scientific evidence of a connection so I don’t think people need to worry."

Which, of course, will have precisely zero effect on the woo-woos.  What the hell does some silly scientist know about, um, science?  There will be an earthquake, you'll see!  (Of course, it helps that the oarfish were found on the coast of Japan, because Japan is -- stick with me, here -- a freakin' earthquake zone.)

The other story comes from a perusal of some twelve million documents that were declassified two years ago by the CIA.  This started all the conspiracy theorists sifting through them, because of course if the CIA wanted to keep an evil conspiracy secret, the first thing they'd do is declassify all the files surrounding it.  But even the wooiest woo-woo takes a while to go through twelve million files, so it was only a couple of weeks ago that we found out that in the files were photographs of...

... "shadow people."

We're told about how spooky and eerie these photographs are, and how they could be aliens or ghosts, or connected to MKUltra or the Illuminati or god alone knows what else.  "The silhouettes are composed of visual noise, almost like television static," we're told, "and have empty voids where their faces should be."  There were two of them, we find out, and each silhouette has a number on it -- 1569 on one, 1572 on the other.

I thought, "Okay, that does sound pretty creepy."  And naturally, I wanted to see the images myself.  So I clicked the link, and here's what I saw:

And I said -- this is a direct quote -- "You have got to be fucking kidding me right now."

This isn't a photograph, it's a drawing.  And not even a very good one.  (In the interest of rigorous research, I looked at the other one, which is identical except for saying "1572" and facing the other direction.)  It is mildly curious that these would be in CIA files, although I wouldn't be surprised if it turns out that the CIA people stuck 'em in there when they declassified the files in order to watch the woo-woos leap about and make excited little squeaking noises.

Which is exactly what happened.

The universe is a wonderful, complex, intriguing, mysterious place.  There is plenty to investigate, plenty to be amazed at, without making shit up or stretching pieces of observable evidence to the snapping point.  So let's all calm down a little, okay?  I'm sure Japan will eventually have another major earthquake (cf. my previous comment about earthquake zones), and I'm also sure there'll be weird random things in the CIA files, whether or not my surmise about people sticking them in deliberately to stir the pot turns out to be true.  But grabbing those little pieces of data and running off the cliff with them is not advisable.

Confirmation bias, unfortunately, makes a terrible parachute.

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A particularly disturbing field in biology is parasitology, because parasites are (let's face it) icky.  But it's not just the critters that get into you and try to eat you for dinner that are awful; because some parasites have evolved even more sinister tricks.

There's the jewel wasp, that turns parasitized cockroaches into zombies while their larvae eat the roach from the inside out.  There's the fungus that makes caterpillars go to the highest branch of a tree and then explode, showering their friends and relatives with spores.   Mice whose brains are parasitized by Toxoplasma gondii become completely unafraid, and actually attracted to the scent of cat pee -- making them more likely to be eaten and pass the microbe on to a feline host.

Not dinnertime reading, but fascinating nonetheless, is Matt Simon's investigation of such phenomena in his book Plight of the Living Dead.  It may make you reluctant to leave your house, but trust me, you will not be able to put it down.