I’ve got a whale of an underwater fairy tale to tell. A few hundred meters down in the ocean there is a little larvacean, let’s name her Elsa, about the size of your finger. Elsa is alone, she’s just abandoned her home, but don’t worry she has the power to build a new one. She gets to work building her new mansion in miniature at first before she pumps it with water, filling it up like a balloon that’s more than three feet across. Now that might not seem like much of a structure, but compared to our little Elsa, it’s as massive as a five-story building. She now lives in a glorious palace but instead of ice, our little Elsa has built it out of snot. 

You read that right; giant larvaceans build what scientists playfully call “snot palaces.” These are fragile and transparent structures made of mucus secreted from their heads which helps larvaceans filter food to eat. Giant larvaceans have beaver-like tails which they use to pump water through these palaces consisting of two layers. The first layer blocks particles too big for the larvacean to eat, and the second guides the best little bits of food they catch into their awaiting mouth. 

Their methods might be gross, but larvaceans are amazing at filtering water. In just one hour these little guys can filter up to 21 gallons, about half a bathtub full of water. Scientists estimate larvaceans spend about two-thirds of their life filtering, and that nonstop work pays off. Scientists at Monterey Bay Aquarium Research Institute (MBARI) found larvaceans living in the water could filter their entire habitat in just 13 days. To do that, larvaceans must filter the equivalent of 500 Olympic-sized swimming pools of water every hour.  

When their filter homes get too clogged with gunk, the giant larvacean simply abandons it and starts the home-building process anew. Like the worst version of the unhappy couple in every HGTV show, they’re picky about their homes—they abandon one of their slimy mansions almost every day. These abandoned homes are actually a boon for deep sea ecosystems, serving as a crucial food source. 

Evidence also exists to suggest larvaceans are a crucial part of the carbon cycle by constantly trading spaces. Since these snot palaces contain so much debris, they float more swiftly to the ocean bottom, making them less likely to be eaten by organisms on the surface. Through this process they can move carbon photosynthesized by neighboring organisms into thedeep sea to be stored. 

Unfortunately, this same system also can transport microplastics. When larvaceans get microplastics into their filters, they can introduce plastics to new deeper ecosystems, moving those plastics further into the ocean. This is another example of how the plastics we create can end up polluting ecosystems few of us will ever see. That’s why it is so important to curb the production of plastics to keep trash out of the ocean. Take action with Ocean Conservancy now to help keep our ocean plastic-free.