A Sponge Sneeze Feast

November 1, 2023
By Tara Haelle

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Sea sponges will “sneeze” when there are too many particles that are unwanted or too big for them to filter and eat. The sponge will excrete these waste particles in a mucus that collects on the outer surface, which nearby fish will feast upon. Credit: NOAA-OE

Every time you sneeze, your body is taking the opportunity to violently eject allergens, viruses, bacteria, chemicals or other particles trying to invade your nose that don’t need to be there. It’s waste that might even make you sick if your body didn’t force it out. But what if sneezing was also how you cleaned your entire body, like taking a shower? That’s how ”sneezes” are for sea sponges. And the sponges take their time with their body-cleansing too—up to half an hour for a single sneeze!

Sponges gather their food by pulling in water through various openings and then filtering food particles out of the water before pushing the water back out. But since sponges are firmly attached to the bottom, they can’t move away from dirty water if it becomes polluted with too many particles they can’t eat. As particles it can’t use or particles that are too big to eat build up in the sponge, it needs a way to get rid of them. And that’s where sponge sneezing comes in.

Unlike a human sneeze, which only takes a second or two and sends particles traveling from 100 to 200 miles per hour, sponges take their time slowly pushing mucus full of waste products out the same openings it uses to draw in water. As the mucus collects on the sponge’s outer surface, it becomes a feast for nearby fish because the sponge has concentrated many food particles in the mucus. The fish benefit because it would take a lot more work for them to pick so many particles from the water on their own. And, when fish eat the mucus from the sponge, it clears the openings for the sponge to continue pulling in water, as scientists observed with Aplysina and Chelonaplysilla sponges last year.