'Some organic matter exists in the water surrounding the coral reef, but most of it is not concentrated enough for other animals to eat. 'We also observed fish and other animals feeding off of the sponge mucus as food,' says Niklas Kornder, the first author of the study and a doctoral researcher in de Goeij's research group.

While the mucus may be waste to sponges, the fishes who live around them think otherwise. 2) Time-lapse footage of the massive tube sponge Aplysina. Occasionally, sponge tissue will contract and push the waste-containing mucus into the surrounding water.ġ) Time-lapse footage of the Indo-Pacific sponge Chelonaplysilla sp. In videos that the authors included in the paper, you can see the water inlets slowly release mucus, and the mucus will accumulate at the surface of the sponge. This is when the 'sneezing' mechanism comes in handy. 'These are sponges they can't just walk to somewhere else when the water around them gets too dirty for them to handle,' says de Goeij. They draw in and eject water from different openings, and sometimes the sponges will suck in particles that are too big. Sponges gather food for themselves by filtering out organic matter from the water.

But both sponge and human sneezes exist as a waste disposal mechanism,' says de Goeij. A sponge sneeze takes about half an hour to complete. 'Let's be clear: sponges don't sneeze like humans do. While the field has known about this behavior for years, the authors of this paper show that these sneezes get rid of materials the sponges cannot use. 'Our data suggest that sneezing is an adaptation that sponges evolved to keep themselves clean,' says Jasper de Goeij, a marine biologist at the University of Amsterdam and the senior author of the paper.

How to get sponges to move out