Made possible

Gathering knowledge for efficient beach cleanups

Foto van meeuw met plastic beker in bek
images: Chaiya Pruek and Robert Plesko

If we want to tackle the plastic problem as efficiently as possible, we’ll need to remove plastic waste from the ocean as quickly as possible. It would obviously be even better to prevent it from ending up there in the first place, but that just isn’t realistic, unfortunately, Erik van Sebille says about the main takeaway from five years of research on ocean plastics. Van Sebille has been studying how things — plankton, fish, but especially plastics — are carried along by ocean currents. To this end, he and his team have developed a computer model that can simulate the trajectory of virtual plastic particles in order to pinpoint the origin and ultimate destination of ocean plastic waste.

North Sea and Wadden Sea

We can then use that knowledge to tackle the plastic problem. “Beaches are the most effective place to clean up plastic. The plastic waste on beaches is easy to reach and hasn’t been broken down into tiny particles yet.” Once it has been out in the ocean for a while, it will gradually fragment from large macroplastic fragments into smaller and smaller particles that are harder to remove. Most of the fragmentation process takes place on beaches. Plastic waste can eventually fragment into so-called nanoplastics that are not even visible to the naked eye and are almost impossible to clean up.

That means cleaning up beaches is a good way to tackle the problem of ocean plastics. So what is the most effective approach? “You could just go to the beach on a nice day and get started. If you want to be effective and clean up on a large scale, though, you’ll need to figure out where and when the most plastic washes ashore. You can then clean everything up on the spot.”

Van Sebille has been working with Stefanie Ypma and the Galapagos Conservation Trust over the past few years to develop a predictive tool for the Galapagos Islands, a unique and fragile ecosystem that is currently under huge threat from plastic waste. He now aims to do the same closer to home, in the North Sea and the Wadden Sea. Siren Rühs, a postdoc working in Van Sebille’s research group, will conduct this research building on the experience gained in the Galapagos. Rühs: “The Galapagos tool is a proof of concept for our approach to identifying the most effective clean-up sites. In the case of the Wadden Sea and the North Sea, we’ll be factoring in more information on regional ocean dynamics, like tidal movements and the water receding from the Wadden Sea.”


As Rühs explains, it will be crucial to validate the model’s output in the real world. This will require drifters: reusable, floating buoys the size of a frisbee, with built-in GPS. The drifters are carried by the same ocean currents as the plastic, and their location data provide valuable information that can be used to verify the model’s output.

The Utrecht University Fund has launched a fundraising campaign to help Van Sebille and Rühs finance these drifters. The target amount of €25,000 covers the purchase of some 40 to 50 drifters, enough to map variations in the ocean currents. In addition to being useful, that process is also fun to observe, as Van Sebille explains, People can also track the drifters in real time on a website, and they can even name their own drifter. That means you’ll be able to monitor currents in the North Sea and the Wadden Sea in real time soon.

Foto van Erik van Sebille

Prof. dr. Erik van Sebille
Erik studied oceanography at Utrecht University and pursued a post-graduate degree at Imperial College London. He served as a lecturer at the University of Miami (USA) and University of Sydney (Australia) and was named professor of Oceanography and Public Engagement at Utrecht University in 2021.

Foto van Siren Rühs

Dr. Siren Rühs
Siren is a physical oceanographer and has been working as a postdoc at Erik van Sebille’s research group since January 2022. She previously studied and obtained her PhD at the University of Kiel in Germany.


You can also contribute to the ongoing research on a plasticfree North Sea and Wadden Sea. Erik van Sebille’s project is among the recipients of the Utrecht University Fund’s annual Pay it Forward campaign. Visit the website or donate directly via this link.

You can adopt your own drifter from €500. For more information, please contact

Bequests for a better future

The education and research we conduct at Utrecht University helps to advance humanity. A bequest to science will ensure that new generations of students and researchers can flourish and make their own valuable contributions to society.

You can also contribute to a better future after your own lifetime. Alumni donations are crucial to the University and help us to promote student development and facilitate groundbreaking research. A bequest to science will help us resolve societal problems and create a better world for everyone. Every donation helps — no matter how large or small — leaving a sustainable legacy for future generations.

A bequest or legacy in support of the University can be put to various uses, such as the advancement of scientific research and student scholarships. However, your bequest could also make a huge difference to the University Museum or the Botanical Gardens.

Please contact Robbert Jan Feunekes for more information about the various options (, 06–44225014).

Foto van Geke Poolen

Geke Poolen (25) is researching the use of artificial intelligence in predicting recurrent thrombosis. Her research is partly funded through the bequest of Medicine alumna Annie van Leerzem (1933–2018).

Visit this website for more information.