From Kiel to Apenrade and back: On the trail of plastic
ALKOR expedition AL635 investigates micro- and nanoplastics in the German-Danish coastal region
July 1, 2025/Kiel. This week, the ALKOR expedition AL635, led by the GEOMAR Helmholtz Center for Ocean Research, set off for the western Baltic Sea in the German-Danish border region. The aim of the expedition is to systematically record the distribution of micro- and nanoplastic particles in the coastal area, to analyze their properties and to better understand possible sources of input. The expedition is part of the Interreg 6A project PlastTrack. On Friday, July 4, the ship will stop in Sonderborg to give the public an insight into the research.
For the second time, scientists from the PlastTrack project are conducting an expedition to record and quantify the distribution of plastic particles in the western Baltic Sea. They want to gain a better understanding of where the plastic particles come from, how they are transported in the water and what effects they have.
The AL635 expedition is part of the Interreg 6A project PlastTrack (Technological platform for micro- and nanoplastics tracking), in which the GEOMAR Helmholtz Centre for Ocean Research Kiel is collaborating with the Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research (AWI) and the University of Southern Denmark (SDU), among others. The aim of the project is to record plastic pollution caused by micro and nanoplastic particles (MNP) in the Baltic Sea and to test and further develop new methods.
In the sea, plastic particles are found both on the surface and at the bottom of the deepest oceans, and ocean currents transport them all over the world. Thousands of tons of plastic end up in the Baltic Sea every year. Sampling showed microplastics in 28 percent of all fish examined. Tiny plastic particles (microplastics) are produced for various consumer applications, such as cleaning agents, or come from the decomposition processes of larger pieces of plastic.
Methods for sampling plastic particles
During the expedition, various methods will be used to sample microplastics. For example, the Neuston catamaran can be used to take samples near the water surface, as some plastic particles are light and float in salt water. Other instruments can take sinking particles from deeper water layers or filter different particle sizes from the water. Some of the samples are analyzed directly on board using special cameras or spectroscopic measurements. Further methods are then used in the laboratories at home to analyze very small particles in particular.
Challenges in detecting micro- and nanoplastics
Expedition leader Prof. Dr. Anja Engel, Professor of Biological Oceanography and Head of the Marine Biogeochemistry Research Unit at GEOMAR, explains: “Nano-particles are 1000 times smaller than microplastics and can no longer be seen with the naked eye. We are currently unable to identify nanoparticles in the environment because there is a lack of standardized methods for sampling these small particles, especially in the sea. In the PlastTrack project, we are working on solutions and methods to detect microplastics and nanoplastics in the environment more quickly and in a more targeted manner,” says Anja Engel.
From Kiel via Flensburg to Sonderburg and Apenrade
The route runs clockwise through the German-Danish border region of the western Baltic Sea: after starting in Kiel, the ALKOR will sail along the Schleswig-Holstein coast to the Flensburg Fjord. The northernmost stop will be Apenrade, before sailing around the Danish island of Als and along the Schleswig-Holstein coast back to Kiel.
There will be a stopover in Sonderburg on Friday, July 4. In the afternoon, the research vessel will moor at the pier in front of the Multikulturhuset cultural center, where there will be an exhibition and a hands-on station. All interested parties are invited to find out more about the work of the researchers.
Background: PlastTrack
The PlastTrack project is funded by the European Union as part of Interreg Germany-Danmark with around 1.74 million euros. GEOMAR is collaborating with the Mads Clausen Institute, lead of the project and the Danish Molecular Biomedical Imaging Center, as well as the Alfred Wegener Institute Helmholtz Center for Polar and Marine Research (AWI), NEWTEC Engineering and CLEAN Denmark. Since 2023, the researchers have been investigating the dangers of plastic pollution for humans and the environment and developing instruments to combat it. The aim is to create an open platform that compares and evaluates the data collected. For example, new tools will help to improve sampling and monitor the transformation and degradation of materials.
Expedition at a glance:
Name: ALKOR AL635 (as part of PlastTrack)
Cruise leader: Prof. Dr. Anja Engel
Period: 30.06.2025 – 11.07.2025
Start and end: Kiel
Cruising area: western Baltic Sea
Links:
https://www.geomar.de/forschen/expeditionen/detailansicht/exp/378381 Expedition AL635
https://www.plasttrack.eu/ Webpage PlastTrack
https://www.geomar.de/entdecken/plastikmuell-im-meer Plastic waste in the ocean
Images:
http://www.geomar.de/n9936 Images for download
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Phone: +49 (0)431 600-2802
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