Achoo! Oops… Who’s hungry for some mucus?

A Great Barrier Reef sponge (Chelonaplysilla) ‘sneezes’, expelling mucus which is quickly gobbled up by waiting organisms. Credit: Current Biology/Kornder et al.

Have you ever seen a sponge sneeze?

Now, thanks to a new study from the University of Amsterdam, you can view the whole process close-up in stunning detail.

Sponges are some of the oldest multicellular organisms and although the sneeze-like process has been known about for some time, this research shows why it occurs.

“These are sponges; they can’t just walk to somewhere else when the water around them gets too dirty for them to handle,” says Jasper de Goeij, senior author of the paper released in Current Biology.

Don’t expect a human-like sneeze though – localised, energetic and over in a split second although sometimes accompanied by catastrophic results.

“The waste-dispelling ‘sneeze’ evolved by sponges takes about half an hour to complete. But both sponge and human sneezes exist as a waste disposal mechanism,” says Jasper de Goeij, senior author of the paper released in Current Biology.

As sponges suck in water, filtering out particles they can use for food, they sometimes also inhale particles that are too big. The water inlets within the sponge’s tissue gradually release mucus, which is expelled outwards along with the waste particles upon contraction and expansion of the sponge.

“Bon appetit,” say waiting fish and other organisms as they tuck into the biological buffet.

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Read more: Ocean creatures mucus to catch their food

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The sponge actually plays an important role in feeding these animals: “Some organic matter exists in the water surrounding the coral reef, but most of it is not concentrated enough for other animals to eat. Sponges transform this material into edible mucus,” says Niklas Kornder, the study’s first author.

Time lapses illustrating how other reef fauna scavenge on the material released by sponges. Credit: Current Biology/Kornder et al

There is still much to understand about these simple-looking but surprisingly adaptable creatures, including how and why the mucus moves along defined pathways on the surface of the sponge before it accumulates pre-expulsion.

“Our findings highlight opportunities to better understand material cycling in some of the most ancient Metazoans”, say the paper’s authors.

Let’s all be grateful that human bodies don’t work the same way…