The sea squirts have a filter covered with mucus. It catches tiny particles in the water.

This creature, which has no brain, can clean the ocean and become fuel

The sea squirt starts its life as a small larva with a small brain, but then it finds a place to live.

Have you ever heard of the sea squirt before?

If not, you're probably in for a surprise.

It lives without a brain yet can still do remarkable things.

It cleans our oceans, can become fuel, and can be used to make minced meat.

Giorgia Carnovale (right) works for the nonprofit organisation Marea. She wants to bring life back to the Oslofjord.

Loses its brain

The sea squirt starts its life as a tiny larva.

At the very beginning, it has a small brain that helps it find a place to live.

When it settles in a suitable spot, like under a pier, it loses its brain mass, according to the Great Norwegian Encyclopedia (link in Norwegian).

This is actually a clever adaption.

After all, who needs a brain if you’re just going to stay in one place?

The sea squirts float around as small larvae until they find a place to attach themselves. There, they remain.

Works as a cleaning pump

Even without a brain, the sea squirt has a lot going for it.

“It’s shaped like a tube and functions as a cleaning pump,” says marine biologist Giorgia Carnovale.

Plankton and bacteria are sucked in at one end.

Portrait photo of a young woman with glasses.
Giorgia Carnovale is a marine biologist. "Sea squirts are fantastic," she says.

“And then they have a mucus-covered filter that catches tiny particles in the water. That's how it gets its food,” says Carnovale.

Clean seawater comes out the other end.

“It can clean three to five litres of seawater per hour,” she says.

Adopt a sea squirt hotel

Carnovale works at Marea, an organisation dedicated to preserving the Oslofjord.

“Growing and planting sea squirts is a great way to clean seawater,” says Carnovale.

This is why Marea has introduced what they call sea squirt hotels.

You can get involved and make a difference:

“Yes, you can adopt your own sea squirt hotel in the Oslofjord,” says Carnovale.

These hotels are buoys anchored to the seabed.

This is what a sea squirt hotel looks like. A buoy at the bottom is enough for the sea squirts to attach themselves.

Sea squirts can ‘check-in’ by attaching themselves to these buoys.

“They then act as cleaning pumps,” she says.

One buoy can accommodate up to 1,000 sea squirts.

They can clean the equivalent of 1,000 bathtubs of polluted water in the Oslofjord each day.

Everything from car to plate

“The sea squirt is the only animal in the world that can create cellulose,” says Carnovale.

This happens when it continues to build its tube. Cellulose is found in all the world's trees and plants and is what we use to make paper, among other things.

The sea squirt's properties make researchers think big.

“Some believe that the cellulose can be turned into fuel for cars. Others think the animal should be used for food,” says Carnovale.

They have been doing that for a long time in Japan and Korea, so why not here in Norway?

A group of biologists is on the case.

They have started the company Pronofa and are making minced meat from a species of sea squirt called Ciona. You can read more about it here.


Translated by Alette Bjordal Gjellesvik

Read the Norwegian version of this article on

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