The ocean modeler

OCCR researcher Charlotte Laufkötter studies the effects of climate change and plastic pollution on the world's oceans. Step by step, the ambitious marine scientist is climbing the academic career ladder.

How does a researcher find a topic? Sometimes it starts with something rather insignificant, such as a walk on the beach. Like many other tourists, Charlotte Laufkötter was concerned to see some of the world’s most beautiful beaches littered with plastic. "These experiences got me thinking," says the researcher. Later she found out how little is actually known about the global phenomenon of plastic pollution in the ocean. More research was clearly needed. Charlotte Laufkötter had found her topic.

Well, it wasn't quite as simple as that, and this story can’t be told in just a few words. It begins far from the sea in the German city of Mönchengladbach. A small child devours atlases and dreams of the ocean. "The sea has always fascinated me, even though we never went there as a family," says Charlotte Laufkötter. "I was a bookworm and knew early on that I wanted to be an ocean scientist."

From computer science to oceanography

But her father, a mathematician, advised against it. Job prospects were far too uncertain, so he convinced his daughter to study computer science. In retrospect, Charlotte Laufkötter thinks it wasn’t a bad choice because she likes programming. And without this background, her career would probably have taken a different course. But after a few years of study, she realized that she wanted more. So she did an internship at the Alfred Wegener Institute for Polar and Marine Research in Bremerhaven, which she enjoyed so much that she managed to minor in oceanography in Bremen while majoring in computer science in Aachen. The researcher then did her dissertation on environmental physics at ETH Zurich. She investigated how the production of biomass in the ocean reacts to climate change.

If you ask Charlotte Laufkötter about her profession today, she’ll give you a two-part answer. First: ocean scientist. Second, and more precisely: modeler of the ocean’s biogeochemical cycle. "That verbal monstrosity is linked to the fact that my field of research is very interdisciplinary," she says almost apologetically.

Plastic waste stays close to the shore

Thanks to this special background, now Charlotte Laufkötter is breaking new scientific ground and providing insights into how plastic waste is polluting the world's oceans. For example, her modeling shows that most of the plastic does not end up out in the open ocean, as previously thought. Rather, it lands on beaches or drifts close to the shore. This was shown in a recently published study that she co-authored with one of her doctoral students.

The study found that the proportion of stranded plastic is highest in the regions of the world with the largest sources of plastic waste. These include regions such as Southeast Asia and the Mediterranean Sea. According to current estimates, anywhere from 1-12 million tons of plastic ended up in the world's oceans last year. For her current research project, the Bern-based modeler is trying to estimate how much plastic in total has landed in the ocean over the past 25 years.

Oceans apart

Charlotte Laufkötter works with the ocean mainly from afar. Fieldwork on the ocean? That has only happened once so far, on a research ship between Spitsbergen and Greenland. The daily work of this marine scientist looks different: On the one hand, she mulls over research questions and possible hypotheses and discusses these ideas with her colleagues. On the other, she programs models and feeds them with measurement data. "The crucial thing is to take into account the uncertainties of the parameters," says the modeler. "We calculate what the world might look like under the assumptions we’ve made. There is no such thing as the perfect model."


The proportion of plastic that washes up on the beach is greatest where there are the largest sources of plastic waste. These include areas such as Southeast Asia and the Mediterranean. Concentrations are lowest in sparsely populated regions such as the polar regions, the coast of Chile and parts of the coast of Australia.

Japanese TV appearance

Charlotte Laufkötter's most sensational publication to date was not about plastic waste, but about the consequences of climate change. In an article in the renowned journal "Science," she explained that heat waves in the world's oceans have become over 20 times more frequent due to human influence. They destroy ecosystems and damage fisheries. Worldwide, the media showed great interest in this article. The Bernese researcher gave an interview to the Japanese state television station NHK, among others. Despite all the attention, Charlotte Laufkötter says: "I don't want to be known for this publication, but for my own topic."

In fact, she has only dealt with marine heat waves relatively briefly -- on an academic excursion, so to speak. After a postdoc at Princeton University, the oceanographer was offered another postdoc position at the University of Bern. This was in the research group led by Thomas Frölicher, who has been working on ocean heat waves for some time. But Charlotte Laufkötter was actually in the starting blocks for setting up her own group. The topic: marine plastic pollution.

She bet on this research area when applying for a grant from the Swiss National Science Foundation (SNSF). Her reasoning: Although the topic is highly relevant to society, only a few researchers are working on it. To a certain extent, this is a unique selling point -- an advantage that shouldn’t be underestimated in the highly competitive academic job market. Charlotte Laufkötter's track record and her topic were convincing: In 2018, she received a coveted Ambizione fellowship from the SNSF. It runs for four years and allows her to set up her own small research group.

A lot of freedom, little security

And to anyone who now thinks that Charlotte Laufkötter is only dealing with plastic waste because it was a hot topic: "I wouldn't deal with subjects that don't interest me personally and that don't seem relevant to me," she says. The ambitious researcher also sees scientific freedom as a kind of compensation. "At this stage, my career is very uncertain and requires a lot of sacrifices -- that has to be offset somehow!"

The modeler has long been planning the next step on the path that will one day lead to a permanent position as a professor -- if all goes well. She has applied to the European Research Council (ERC), the EU institution for funding outstanding scientists, as well as the SNSF's Eccellenza program, which funds SNSF professorships. Both proposals focus on the biological carbon cycle in the ocean. In a nutshell, Charlotte Laufkötter wants to better understand the transport of organic material, especially carbon, into the deep ocean. To do this, she plans to use data from the Argo mobile observing system of the world's oceans. It consists of a fleet of around 4,000 automated drifting buoys that measure temperature, salinity and currents. Increasingly, chemical and biological components are also being observed. Charlotte Laufkötter wants to combine this part of the so-called Argo-float data with models for her basic research. 

Back to the child who imagined the sea. The dreamy enthusiasm of that time has given way to a very concrete passion. "What fascinates me so much about the ocean: It's all three-dimensional and is also influenced by the currents. You always have to think about the context there." Charlotte Laufkötter likes things that are complex rather than simple. She’s interested in the big picture rather than the details.

(August 2021)