Interview: "Arctic methane seeps are microbial hotspots and serve as analogues to icy moons"

In this interview, PhD researcher Lisa-Marie Delpech delves into her work on Arctic microbial ecology, highlighting the importance of studying methane seeps for both climate research and astrobiology.

Can you describe yourself briefly, and what is the focus of your research? Why is it important?

My name is Lisa-Marie, I am a PhD candidate in France, affiliated with UiT The Arctic University of Norway through iC3 and the project METHANICE.

My research focuses on microbial communities in the ice and water reservoirs of emerged, ice-covered methane seeps in the Arctic. These sites are not only hotspots of Arctic methane emissions but also microbial hotspots, and serve as analogues to icy moons, offering insights into how life might harness energy in such environments.

I study where the carbon and energy from methane go after its release, and whether the ice-covered winter season is microbiologically active. This is key for linking microbiology and geochemistry and for predicting changes as Arctic seasonal cycles are disrupted.

Picture: Lisa-Marie samples water for geochemistry and microbiology at the Rypefjellbreen pingo, where the seeping fluid is rich in methane. Credit: Gabrielle Kleber.

Why is it important to study these systems now?

Very little is known about the microbiology of Svalbard’s emerged terrestrial methane sources. The cryosphere has long been overlooked in microbial studies, yet it is among the habitats most threatened by climate change.

These seep systems are particularly dynamic, with seasonal ice that could soon be destabilized as seasons are disrupted in the Arctic. We want to understand the ecological roles of microorganisms while the ice cover is still stable.

As glaciers retreat, more such systems emerge, making it urgent to study them now and assess how microbial processes influence the methane feedback loop.

How are you conducting your research?

I mainly rely on field sampling, collecting ice and water to capture microbial material. I use high-throughput sequencing to identify the community members and their functions.

I combine this with quantification of microbial abundances, and geochemical analyses to measure oxidants and reductants — the “powers” of microbial life — in the environment. 

We also run incubation experiments under different conditions to test how communities respond to changes such as oxidation events or freeze–thaw cycles. This multidisciplinary approach allows us to diagnose these systems and better understand their ecological dynamics.

Figure: Sampling of sea ice in front of Paulabreen, where under-ice methane has been spotted. The aim is to see whether microbial communities in ice use this methane. Credit: Gabrielle Kleber.

Where are you conducting this research?

Most of my fieldwork takes place in Svalbard, though Greenland is also a possible area for future studies. We focus on “open system pingos” in ancient deglaciated valleys like Adventdalen, as well as areas in front of retreating glaciers where younger methane-rich systems are forming.

Picture: The seeping methane-rich fluid under the ice cover of Riverbed pingo in Adventdalen creates a hill-shaped frozen structure. Credit: Lisa-Marie Delpech.

Have you done any field trips as part of your PhD?

Yes, I've conducted fieldwork in Svalbard both before and during my PhD. I received an Arctic Field Grant from the Research Council of Norway, which allowed me to conduct spatial sampling of pingos on Svalbard.

Microbial ecology is very much a field-based science, and these field campaigns have been an unprecedented chance for me to truly appreciate the systems I am trying to elucidate with my research.

What is BIOFEEL, and how are you involved?

BIOFEEL is the name of my team in La Rochelle, focusing on carbon cycles across different ecosystems. It is an interdisciplinary team working on everything from chemistry modeling of carbon fluxes to higher trophic levels such as fish and birds.

How did you end up working with UiT?

My first master’s internship was at UiT, where I discovered microbial ecology while studying the impacts of terrestrial inputs on an Arctic fjord’s coastal microbial communities.

That experience sparked my interest in microbes and the polar regions, and ultimately led me back to the Arctic for my PhD research.

Have you always aspired to have a career in science?

Yes, though I wasn’t initially sure of the field. I was more attracted to mathematics and physics but wanted to contribute to environmental research, which drew me to biology.

Microbial ecology — especially in polar regions — captivated me during my master’s internship. I also enjoy the interdisciplinary nature of my current work. After all, you don’t often get the chance to see the Arctic landscapes as a mathematician!

What does an ideal day off look like for you?

I’d like to say scootering down a glacier or hiking in mountains, but that’s not very common in La Rochelle. In winter, I enjoy knitting and cooking; in summer, gardening and anything outdoors. I also love swimming, running, and biking in my free time.

Do you have any last words or a motto you'd like to share?

Microbes might be the only form of life some environments ever host, yet they’re often misunderstood.

Most microbes are harmless and possess extraordinary metabolic capabilities that significantly impact their environment. Raising awareness about their importance is essential.

My personal motto is: “open and reproducible science.” Behind every dataset lies enormous human, environmental, and economic effort. I believe scientific data should not be lost in digital archives but shared openly for others to build upon.

Lisa-Marie Delpech is an iC3 affiliated PhD student working at the University of La Rochelle, France and at the Arctic University of Norway (UiT), Norway. To find out more about her work, please check out her list of publications, or contact her by email.