Thanks to the Monterey Bay  Aquarium and their research and technology partner MBARI for partnering  with us on this episode of SciShow.

They worked together on an  exhibition, “Into The

Deep: Exploring Our Undiscovered Ocean,” to give  visitors to the Aquarium a rare look at some of the animals that thrive in the least-explored area of the planet, the deep sea! [♪ INTRO] Imagine you are a swimming animal stuck in a never ending game of The Floor is Lava. You spend your entire life  moving through the water, never touching the ocean floor. Chances are, you’d get pretty good at swimming! Well that is exactly what the  life of a gossamer worm is like.

And their swimming isn’t  just efficient and elegant. It could help researchers develop  the next great marine robots. Gossamer worms are holopelagic,  which means that they live their whole lives in the water  column, that area above the ocean floor.

These peanut-sized, gelatinous  sea worms are part of a group of segmented marine worms called polychaetes. But unlike many of their  wiggling underwater cousins, gossamer worms lack two of the key  defining features of polychaetes. The word polychaete means ‘many bristles’, because almost all species in  this group have bundles of tough, brush-like spines called chaetae  at the ends of their little feet.

That is, except gossamer worms. Their feet are naked. Gossamer worms also don’t have septa, thin bands of tissue that give  worms their segmented, bubbled look.

Gossamer worm bodies look  more like a cross between a balloon animal and a fern frond. And those differences are  more than just aesthetic. It means gossamer worms move in a totally unique and downright mesmerizing way.

It’s like a combination of slithering  side to side and spirit fingers. See, gossamer worms have thirteen  or more pairs of parapodia: little feet that look a bit like paddles. And each parapodium moves  like an oar through the water.

But unlike oars of a rowing boat, those  feet don’t all stroke at the same time. They move in a beautiful pattern  called metachronal paddling, kind of like a wave rippling  through a crowd at a football game. And, at the same time, the worms  also wiggle their flexible, fluid-filled bodies from side to  side in what’s called a body wave.

Their unique swimming style makes them the perfect subjects for  studying underwater movement. And that’s just what scientists from MBARI, the Monterey Bay Aquarium  Research Institute, have done. They went out into the deep ocean  and, using a remotely operated underwater vehicle, sucked up  several gossamer worms to study.

Then they filmed the worms  using high speed cameras as they swam around in transparent  tanks, both at sea and back on land. Using digital markings on different  points on the worms’ bodies, the researchers saw that each  movement of the parapodia had a power stroke and a recovery stroke. The power stroke pushes the animal forward, and the longer recovery stroke brings the legs back into their starting  position, ready for the next push.

And, by shining a laser on the worms,  researchers could see how the worms have optimized their swimming motion to  increase thrust in the power stroke, and reduce drag in the recovery stroke. During the power stroke, the  parapodia lengthen before they swish through the water, helping them  increase thrust and drive them forward. And during recovery, the parapodia contract again, reducing drag so that the  parapodium glides through the water.

And there was one more piece  to this fancy footwork puzzle. When researchers slowed the videos down, they noticed that the two fleshy  ends of each parapodium, called rami, would spread out as the worms  pushed themselves forward and then contract again during recovery. By spreading their toe-like rami, the worms  could increase the foot’s surface area, once again increasing thrust  and giving them more power.

But metachronal paddling isn’t the only thing helping gossamer worms dance through the water. Using mathematical models, researchers  figured out that the body wave isn’t doing much on its own  to help the animals swim. Only about a third of the  swimming speed comes from it.

Instead, the body wave amplifies the  thrust of each of those little feet. On the one hand, or on the one  foot, it gives each paddling foot room to angle itself further forward  and then end up further back. That means the angle each leg can make relative to the body is  bigger, resulting in more thrust.

Second, the timing of the body wave  and the foot paddling is synced so that the feet are far out from the body when they’re doing their power stroke, for maximum efficiency. Now, unpacking the details of how  these elegant creatures swim is helpful for understanding how they spend literally  their entire lives paddling along. But it could also help inspire new ways  for robots or vehicles to swim underwater.

For example, the researchers propose  that you could make the propellers of an underwater craft more flexible, to  mimic the gossamer worms’ paddle feet. Or, engineers could try and make  the body of the robot flexible to simulate the way the gossamer  worm sways side to side.   That might be a bit trickier, given the  whole thing has to be watertight and all. But it might just start out as dividing  the body up into smaller, rigid sections.

Kind of like those wiggly  snake toys you had as a kid. And who knows, those new underwater  robots could help scientists explore more of the deep ocean, take  scientific measurements, search for sunken objects… and even,  find other awesome organisms like the gossamer worm. We teamed up with Monterey Bay Aquarium  and MBARI to bring you this episode!

They are super excited for folks  to learn about the deep sea. You can make like a gossamer worm and paddle on over to their websites and social media. MBARI’s YouTube channel has  awesome videos about the deep sea, and on the Aquarium’s website, you can  make a donation to support their exhibits, education programs, and ocean conservation work.

And also, the Aquarium’s YouTube  channel posts these, like, amazing lofi mixes set to relaxing  Aquarium videos that are perfect for getting your work done, if you  need somewhere to go after this! [♪ OUTRO]