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  • Happy World Oceans Day!

  • We're celebrating Earth's oceans this whole week, with a series of videos about

  • the oceans.

  • Turns out they're full of some pretty weird things, and there's a lot going on down

  • there that we still don't understand.

  • And the deepest oceans are among the least understood habitats on Earth, because they're

  • hard for humans to explore.

  • Never mind that it's dark and scary down there, the pressure's about a thousand times

  • the pressure at sea level, which would compress the human body into a messy pulp.

  • But there is life down there, and plenty of it.

  • We can study that life using either very long nets or remotely operated vehicles, known

  • as ROVs. And each year, we're discovering new, amazing species that are most at home

  • in the ocean depths.

  • These are 8 of the strangest deep sea creatures we've discovered, just since 2009.

  • [Music Playing]

  • We'll start off with the ninja lanternshark, which was brought up from deep waters off

  • Central America.

  • The species was officially described in 2015 by a research team led by marine biologist

  • Victoriasquez .

  • Four of her cousins, aged 8 to 14, helped coin the shark's common name: ninja lanternshark.

  • Which is actually really descriptive.

  • Their skin contains bioluminescent organs called photophores, which give the shark an

  • eerie green glow. These might help it do things like attract mates, communicate with other

  • sharks, or lure prey.

  • But the ninja lanternshark is very different: it has fewer photophores and it has jet-black

  • scales, which make it a great stealth hunter.

  • It may not carry throwing stars or anything, but it does have some very sharp, asymmetric

  • teeth, the top half are for grasping, and the bottom half are for cutting.

  • Even if you encountered those teeth in their native habitat, though, you probably wouldn't

  • need to worry too much. Ninja lanternsharks are smaller than house cats and probably eat

  • worms and small fish.

  • But not all deep-sea creatures look quite as striking as the ninja lanternshark.

  • Sometimes, they just look like sad, washed-out old socks

  • Especially the sockworms, or Xenoturbella.

  • They're a group of five species, four of which were discovered in 2016 deep under the

  • Gulf of California, using ROVs from the Monterey Bay Aquarium Research Institute.

  • And if you're thinking that their bodies look a little simple, you're right. They've

  • got a mouth, but no eyes, brain, or anus!

  • In fact, they're so weird that scientists have struggled to fit them onto the evolutionary

  • tree of life.

  • Early DNA analysis suggested they could be some kind of strange mollusc that maybe lost

  • some of its organsbut the researchers were misled by contamination from some clam

  • eggs the sockworms had eaten.

  • The evidence from the new species has helped researchers figure out what's up with these

  • sockworms, and these days, they're thought to be some of the simplest animals with bilateral

  • symmetry, a clear left and right side.

  • As for those new species, the furrows in one of the new sock worms reminded researchers

  • of a certain pastry, so they named this species Xenoturbella churro.

  • I'm not sure I'd want one of these guys dipped in chocolate sauce, though!

  • Last year, the cold depths of the East Scotia Ridge near Antarctica revealed some of the

  • habits of a species of crab with some very impressive body hair.

  • First discovered in 2009, they're unofficially called Hoff crabs after David Hasselhoff and

  • his famous chest-rug, but those hairs aren't for keeping the crab warm.

  • Instead, they're used to grow bacteria, which the crabs harvest using their comb-like

  • mouthparts.

  • Researchers from the UK took ROVs down to the polar depths, peering into the private

  • lives of these crabs by examining how they were distributed across the ocean floor.

  • Their lives are mainly organized around volcanic vents, which warm the surrounding water.

  • Males and females cluster together here, growing their bacteria, mating and presumably having

  • a good time.

  • The vents can support up to 4000 crabs per square meter.

  • But there were also Hoff crabs living farther out from the vent, in the colder waters. These

  • all turned out to be mothers, brooding baby crabs under their curled-up tails.

  • The researchers think the vents could be spewing out chemicals that are toxic to the developing

  • crabs. So the new mothers relinquish the safety and warmth of the group, but for the sake

  • of the babies, it's worth it.

  • The Hoff crabs were discovered in 2009, living in vents around 2.5 kilometers below the surface.

  • Which is pretty far down.

  • But just a year later, researchers from Southampton in the UK found some hot smokers twice that

  • deep. At five kilometers down, these are the deepest known volcanic vents in the world.

  • And they're full of life, specifically, a new species of eyeless shrimp.

  • They're found in the Mid-Cayman Rise, a huge seafloor gash caused by two tectonic

  • plates ripping apart.

  • Like the Hoff crabs, these shrimp take advantage of the warmth provided by these volcanic vents,

  • and there are huge swarms of them down there.

  • The vents heat water to around 400oC, the only reason it doesn't boil is because of

  • all the pressure.

  • And just like we humans might enjoy the heat of a bonfire, but only from a safe distance,

  • the shrimps also want to avoid the scalding danger zone.

  • But they need help to avoid bumbling straight into it. Eyes as we know them aren't going

  • to be much help, since it's pitch black down there and the vents don't emit any

  • visible light!

  • The baby shrimp are born with eyes that can sense visible light, since they live a little

  • closer to the surface.

  • But as they mature, they do away with eyes completely, and develop an infrared, heat-sensing

  • organ on their backs to avoid becoming another shrimp on the Barbie.

  • Any list of deep sea creatures wouldn't be complete without an appearance from our

  • favorite underwater horror, the anglerfish!

  • There are more than 200 known species of anglerfish, and this new one, wellit's not pretty.

  • The story of this snaggletoothed brute's discovery doesn't start happily.

  • In 2010, offshore oil rig Deepwater Horizon exploded and sank, spilling 5 million barrels-worth

  • of oil into the Gulf of Mexico, an ecological disaster.

  • Very little was known about what species lived in the area, especially deep underwater, and

  • this made clean-up and conservation efforts a lot harder.

  • Extensive surveys of life in the Gulf discovered fifty new species, including this ugly beast.

  • Those forehead spikes are actually teeth! Its upper jaw is highly mobile, so it can

  • reach all the way up there and grab anything that swims too close to its glowing lure.

  • Female anglerfish also use their lures to attract males, but they only want males from

  • their own species.

  • So each anglerfish species has its own signature lure structure, which affects the fish's

  • appearance in the dark ocean depths.

  • This makes lures great clues to help researchers figure out if they've got a new anglerfish

  • on their hands.

  • This new anglerfish's lures each have a finger-like extension that guides light like

  • a fiber-optic cable.

  • They also have two filaments near the tip, which might mimic wiggling prey.

  • Sometimes you just need to get up-close-and-personal with even the most hideous of species, if

  • you want them to reveal their secrets.

  • In 2012, MBARI's ROVs discovered the Gulf of California's depths are home to

  • the rather graceful-looking harp sponge.

  • Its root-like attachments may look plant-like, but sponges are actually animals, though fairly

  • simple ones.

  • Despite its name, the harp sponge won't be playing you any elegant tunes, it's up

  • to something much more sinister!

  • It spreads out in a fan-shape, with up to six vanes extending from the rooted center

  • to maximize the chances of making a catch.

  • Each so-calledstringis coated in barbed hooks, which snare creatures that happen to

  • pass by and decide the gently waving branches would be a nice place to hang out.

  • The sponge then coats its seafood entrée in a thin membrane and digests it whole.

  • Most shallow water sponges are filter-feeders that capture bacteria or debris and extract

  • the nutrients, but the sparse ocean depths require different tactics.

  • So until around 20 years ago, we didn't know that some sponges eat meat at all.

  • Now that marine biologists have a better idea of what to expect, they've discovered dozens

  • of new carnivorous sponges.

  • And those nodules at the top? They're full of sperm!

  • The bulbs distribute sperm into deep-sea currents, hoping to find the eggs on the strings of

  • other harp sponges.

  • The species we've talked about so far are just some of the new creatures scientists

  • have discovered since 2009.

  • But there are some new creatures that we've seen for the first time in just the last few

  • months! So researchers haven't had time to go through the rigorous process of officially

  • describing them yet.

  • This one is a type of octopus that was found four thousand meters down, near Hawaii, by

  • NOAA's Deep Discoverer ROV.

  • It's so new to science, it might even be a whole new genus.

  • It doesn't have an official name yet. But people have taken to calling itCasper”,

  • after the friendly ghost, and it's not hard to see why.

  • The striking lack of color is pretty strange among cephalopods. Many have astounding colour

  • palettes, thanks to specialized pigment cells called chromatophores.

  • Cephalopods can adjust the behavior of these cells to create impressive displays or melt

  • into the background.

  • But Casper doesn't seem to have any chromatophores, leaving it with a ghoulish white hue.

  • Another surprise was that it's only got one row of suckers running along its tentacles

  • compared to the usual two rows found in most kinds of octopus.

  • How these features might help Casper survive is still a mystery, and it'll probably probably

  • stay that way until we can find more Caspers to study.

  • An even more recent finding, from April 2016, was this stunning jellyfish, captured on film

  • by NOAA's Okeanos Explorer team.

  • The team was on a mission to explore the region surrounding the Marianas Trench, which contains

  • the deepest waters on Earth.

  • This mission has a bunch of objectives, like revealing the trench's geologic history

  • in more detail. But it's also looking for life.

  • Just in the first few days of the mission, which runs through July 10th, the team spotted

  • some deep-sea gems, including this jellyfish, which seems to be completely new to science.

  • It doesn't have a specific name yet, but the researchers' best guess is that it's

  • a form of hydromedusa, and part of the Crossota genus.

  • The red lines are called radial canals, they help link body parts together, including those

  • yellow orbs, which are probably reproductive organs.

  • We don't know how this jellyfish lives, but other Crossota species are ambush predators,

  • so this one might be, too.

  • This could explain how it's behaving here: floating with sprawling tentacles, waiting

  • for something to stumble by into a world of sting.

  • With so much of the ocean still to explore, and new deep-sea research missions happening

  • across the world, this is an exciting time to be interested in life beneath the waves.

  • Thanks to Victoriasquez, Kim Fulton-Bennett, Jonathan Copley, and Theodore Pietsch for

  • their help with this episode, and thanks to all of our patrons on Patreon who make this

  • show possible. If you want to help us make videos like this, just go to patreon.com/scishow.

  • And don't forget to go to youtube.com/scishow and subscribe!

Happy World Oceans Day!

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