Christian Nilsson in the lab. — Christian Nilsson examines the worm Erinaceusyllis simonlledoi in his microscope.

Student fulfils childhood dream - describes newly discovered worm

Published

14 January 2025

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Christian Nilsson has always dreamed of working in deep-sea biology and describing a new species to science. Thanks to hard work and good contacts, both dreams have now been realised.

Christian Nilsson porträtt. — Christian Nilsson tog masterexamen i marina vetenskaper 2024.

Christian Nilsson has been interested in species for as long as he can remember. As a young man, he fished a lot and tried to catch as many species as possible. Now, as a student, he has described a previously unknown bristle worm to science.

"This is so cool. It's a childhood dream come true," he says.

Found on a piece of wood

The project started during his studies on the Bachelor's Programme in Marine Sciences in the spring of 2021. Christian Nilsson, who has always been interested in deep-sea biology, then contacted researchers Thomas Dahlgren and Helena Wiklund, who had been on an expedition to the Clarion Clipperton Zone in the Pacific Ocean.

"I asked if they had any work for me that was suitable as a bachelor thesis. They replied that I could help describe a bristle worm found on a piece of wood at a depth of 4,300 metres. Of course I said yes," says Christian Nilsson.

Piece of wood with worms. — The bristle worm was found on a piece of wood at a depth of 4,300 metres between Mexico and Hawaii in the Pacific Ocean. It was picked up using a remote-controlled underwater vehicle.

Photo: ROV Odysseus/TMC

He started mapping the worm during his 10-week master's thesis, but it takes time to describe a new species to science. He therefore continued the work in his spare time. By examining the worm under a scanning electron microscope, Christian Nilsson realised that this species was different from the other worms in the genus Erinaceusyllis.

"The distinguishing characteristics of this species are that it has no eyes at all, fewer bristles, and that each egg-bearing body segment only bears one single egg."

Nutrient-poor environment

While working as an information officer at the Tjärnö Marine Laboratory during the summer, he had the opportunity to meet several worm experts who gave him valuable tips on how to identify bristle worms. He was also able to borrow camera equipment to take sharp pictures of the worm, which is barely two millimetres long.

"Characteristic of the animals living in these areas is that they have adapted to a life with very little nutrition. As a result, many of the species that live here are small. A piece of wood can therefore become an important source of energy that many species can use," says Christian Nilsson.

The bristle worm Erinaceusyllis simonlledoi is named Erinaceusyllis after the Latin name for hedgehog and simonlledoi after Erik Simon Lledó, one of the scientists who was on board when the species was picked up from the seabed.

Photo: Christian Nilsson/Centre for Cellular Imaging, NMI

In the spring semester of 2023, Christian Nilsson took an internship at the Department of Marine Sciences to finalise a scientific article together with Thomas Dahlgren and Helena Wiklund. In December 2024, it was published in a journal on deep-sea research.

"‘This work has been a great way to get in touch with many people, and a good opportunity to build on my CV. Thanks in large part to this, I have now secured a PhD position at the University of Bergen where I will continue to work on polychaetes and other species living at deep-sea hot springs."