The next time you see a sea sponge, say “gesundheit!” Some sponges “sneeze” regularly to clean up debris of their porous bodies.
As filter feeders, sponges draw in water through entrance pores, called ostia, and filter it through a system of internal channels in search of nutrients. But there are also inedible parts in the water, such as sediment. To prevent unwanted debris from clogging your external pores, a Caribbean tube sponge (Aplysina archeri) uses mucus to trap and sneeze out unwanted particlesNiklas Kornder, a marine biologist at the University of Amsterdam, and colleagues report online August 10 at current biology. To the surprise of the team, they found that the sponge expels its mucus through the same pores through which it absorbs water. яндекс
It’s “like someone with a runny nose,” says team member Sally Leys, an evolutionary biologist at the University of Alberta in Edmonton, Canada. “It’s constantly transmitted, but it goes against the current.”
Researchers knew that sponges used contractions called “sneezes” to move water through their bodies in one direction. Water usually enters through numerous ostia and exits through the osculum, a hole near the top of the sponges.
But when the team captured time-lapse video of a. archeryHe saw tiny specks of mucus coming out of the ostia, moving against the flow of incoming water. The sneeze-like contractions seemed to expel and move the specks along a “mucus highway” across the sponge’s surface to points where they collected in stringy, sticky clumps. Unlike an explosive human sneeze, the sponges slowly and continuously secreted debris-laden mucus from their orifices, with one contraction taking between 20 and 50 minutes, according to the study.
Other marine critters feast on these ocean snot, such as brittle stars and small crustaceans. Scientists see sponges primarily as habitat builders, but the mucus buffet shows they also play an important role as food providers, says Amanda Kahn, a marine biologist at Moss Landing Marine Labs in California, who was not involved in this work.
“There’s a lot to be said for a studio that really puts in the time and watches,” says Kahn. “They let the animals show for themselves what was going on.”
Most sponges appear to sneeze, so it’s probably not just a. archery that uses the counterflow technique, says Leys. The team also noticed similar behavior in an Indo-Pacific sponge (Chelonaplysilla sp). But biologists need to dig deeper to find out how widespread the mechanism is. It’s also unclear exactly what mucus is or how it moves back through the pores.