PhD student Eva Stewart looks at samples in a glass jar.

Eva visited the Museum on school trips but never imagined she'd work there. Being a deep-sea biologist at the Museum is her proudest achievement. Photo by Tammana Begum.

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Behind the Science: Eva Stewart explores how seafloor mining might impact deep-sea invertebrates

PhD student Eva is a marine biologist who studies deep-sea animals from the Pacific Ocean, many of which are completely new to science. Her research is helping us to understand these elusive creatures and work out how we can mine for minerals on the seafloor where they live in an environmentally friendly way.

This interview is part of a series in which we talk to young scientists and researchers about what they're working on.

What are you researching in your PhD?

My research is focused on deep-sea invertebrates, such as worms and crustaceans, that live in the Clarion-Clipperton Zone (CCZ) - a vast region in the central Pacific Ocean that's almost as big as Australia.

There's a lot of industrial interest in mining the deep seafloor in this area. This is because it's abundant in minerals and metals that are thought to be critical to future green technology industries such as electric vehicles.

The CCZ is incredibly biodiverse. Many of the species we collect there have never been found before. It's really important that we find out what lives there so we can understand the ecosystem and protect these creatures from environmental damage.

Part of my work involves describing new species. I'm currently working on a new species of a type of parasitic worm called a myzostomid. We found them living on a starfish from 4,500 metres deep in the ocean. I've been using some of the amazing imaging equipment here at the Museum to CT-scan my specimens and get a complete picture of them and how they attach to their hosts.

PhD student Eva Stewart smiles at the camera.

Eva spent two months exploring and collecting samples from the CCZ in 2021. Photo by Tammana Begum.

Tell us a little more about the CCZ.

The CCZ is an area beyond national jurisdiction, which means no country owns it. A United Nations body called the International Seabed Authority (ISA) aims to ensure that if mining does take place there, it is legal, economically viable and environmentally sustainable. There are various contractors working in the CCZ but none are allowed to start mining yet. They can only undertake exploration and scientific research.

The deep-sea lab at the Museum is working to produce baseline biodiversity data for a number of these contractors, including representatives from the UK, as well as from Nauru and Tonga. The work I'm doing goes towards characterising the biodiversity of the seafloor and publishing it in open-access, peer-reviewed papers. This helps everyone involved improve the quality of the data they produce and provides policymakers with better information on which to make future decisions.

What's the most exciting or challenging thing about your job?

I'm working on organisms that no one else has come across before. I'm starting from scratch with a lot of these animals, which is exciting, as there's so much to discover. I also get to spend quite a lot of time at sea doing field work and collecting more specimens to study, which is an amazing experience.

What's the most common misconception of your job?

When I tell people I'm a marine biologist, they usually imagine scuba diving or snorkelling on tropical beaches. That's what I thought at first too but there's so much more to the oceans than the colourful reefs that people first think of. I spend most of my time working in the lab, which might not be as glamorous but I love it.

PhD student Eva Stewart looks through a microscope at a sample collected from the deep-sea.

Eva grew up in London but she often visited the English coast with family during the holidays. She loved exploring rock pools and her interest in marine biology flourished from there. Photo by Tammana Begum.

Name one challenge you had to overcome as a minority within science.

When I was at university, it was noticeable that nearly all of the lecturers and supervisors I had were male. You see this a lot in science, technology, engineering and maths - the STEM subjects - where the further up the ladder you go, the more male-dominated it becomes. It can be frustrating not seeing yourself represented in the fields you're interested in, particularly when you first start pursuing a career in science. Having female mentors during my thesis has made such a difference.

If there was something you could change about your profession, what would it be?

The sheer amount of unpaid work you're expected to do to get to a certain position is such a big barrier to many people who want to get into science, particularly ecology. I couldn't afford to volunteer or pay to work for three months to progress my career. There seems to be a few more paid opportunities for undergraduates now but there's definitely room for improvement. The whole culture of doing unpaid work needs to change.

What advice would you give women trying to get into the same field as you?

Don't be afraid to ask questions. I used to always fear emailing people because I thought I'd annoy them or I wouldn't get a response. You never lose anything by asking someone something. The only reason I ended up here at the Museum is because I sent an email to my supervisor saying I liked his work and wanted to come and talk to him. He was really receptive to my ideas for my master's projects and I'm still here three years later. There are so many good supervisors out there and you won't find one unless you reach out and talk to them.

Do you have any hobbies?

I do a lot of drawing, painting and print making, often based around science. One of the best parts of this job is that I can incorporate my art into my work. For two of the crustacean species descriptions I'm working on at the moment, I've had to do really detailed drawings of all the different body parts, mainly legs and mouth parts. It's a long process but it's also a lot of fun.