Letting out a sneeze has been one of the oldest and most common ways to get rid of irritants and unwanted waste by many organisms. Now, it has been found out by a group of researchers that sponges, which are one of the oldest animal forms to exist on Earth, do it too. Sea sponges sneeze to unclog their internal filter system which could have been filled by solid wastes. In this way, they play an important role in the cycling of nutrients in many aquatic ecosystems.
The findings were revealed in a research paper authored by Jasper de Goeij, a Marine Ecologist at the University of Amsterdam, and his colleagues. The study published in the Journal of Current Biology on Thursday, also found out that the mucus which the sponges let out is used as food by animals living with them.
In a time-lapsed video, the researchers captured the behaviour of two sponge species- the Caribbean tube sponge Aplysina Archeri and an Indo-Pacific specie of genus Chelonaplysilla. Examining the footage helped them understand a completely different mechanism of particle removal by the multicellular organism. The team said that the contractions were observed in these aquatic organisms earlier as well but the details remained unclear.
“We found a lot of the [ejected] material to be probably inorganic particles, meaning sand, sediment, things that the sponge cannot use that are only maybe clogging the system and it needs to get rid of,” de Goeij said.
He further clarified that sponges don’t sneeze like humans do. “A sponge sneeze takes about half an hour to complete. But both sponge and human sneezes exist as a waste disposal mechanism,” he said.
Water full of nutrients enters the sponges through various tiny pores. The excess water and unwanted materials then get filtered out through different openings. “These are sponges; they can’t just walk to somewhere else when the water around them gets too dirty for them to handle,” said de Goeij explaining that this is when the “sneezing” mechanism comes into play.
In the videos shared by the authors of the paper, water inlets can be seen releasing the mucus slowly, which then accumulates on the sponge’s surface. While the mucus might be a waste material for sponges, the fishes and other animals consider it food, according to Niklas Kornder, a researcher from de Goeij’s team.
Many aspects of the sneezes of the sponge still remain uncertain and more analysis will be required to find out what exactly happens when they sneeze, the researchers said.